RESUMEN
This study evaluated if the cardioprotective effect of Exendin-4 against ischemia/reperfusion (I/R) injury in male rats involves modulation of AMPK and sirtuins. Adult male rats were divided into sham, sham + Exendin-4, I/R, I/R + Exendin-4, and I/R + Exendin-4 + EX-527, a sirt1 inhibitor. Exendin-4 reduced infarct size and preserved the function and structure of the left ventricles (LV) of I/R rats. It also inhibited oxidative stress and apoptosis and upregulated MnSOD and Bcl-2 in their infarcted myocardium. With no effect on SIRTs 2/6/7, Exendin-4 activated and upregulated mRNA and protein levels of SIRT1, increased levels of SIRT3 protein, activated AMPK, and reduced the acetylation of p53 and PGC-1α as well as the phosphorylation of FOXO-1. EX-527 completely abolished all beneficial effects of Exendin-4 in I/R-induced rats. In conclusion, Exendin-4 cardioprotective effect against I/R involves activation of SIRT1 and SIRT3. Graphical Abstract Exendin-4 could scavenge free radical directly, upregulate p53, and through upregulation of SIRT1 and stimulating SIRT1 nuclear accumulation. In addition, Exendin-4 also upregulates SIRT3 which plays an essential role in the upregulation of antioxidants, inhibition of reactive oxygen species (ROS) generation, and prevention of mitochondria damage. Accordingly, SIRT1 induces the deacetylation of PGC-1α and p53 and is able to bind p-FOXO-1. This results in inhibition of cardiomyocyte apoptosis through increasing Bcl-2 levels, activity, and levels of MnSOD; decreasing expression of Bax; decreasing cytochrome C release; and improving mitochondria biogenesis through upregulation of Mfn-2.
Asunto(s)
Proteínas Quinasas Activadas por AMP/metabolismo , Exenatida/farmacología , Incretinas/farmacología , Daño por Reperfusión Miocárdica/prevención & control , Miocitos Cardíacos/efectos de los fármacos , Sirtuina 1/metabolismo , Sirtuinas/metabolismo , Acetilación , Animales , Apoptosis/efectos de los fármacos , Modelos Animales de Enfermedad , Activación Enzimática , Receptor del Péptido 1 Similar al Glucagón/agonistas , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Masculino , Daño por Reperfusión Miocárdica/enzimología , Daño por Reperfusión Miocárdica/patología , Daño por Reperfusión Miocárdica/fisiopatología , Miocitos Cardíacos/enzimología , Miocitos Cardíacos/patología , Proteínas del Tejido Nervioso/metabolismo , Estrés Oxidativo/efectos de los fármacos , Coactivador 1-alfa del Receptor Activado por Proliferadores de Peroxisomas gamma/metabolismo , Fosforilación , Ratas Wistar , Transducción de Señal , Sirtuina 1/genética , Sirtuinas/genética , Proteína p53 Supresora de Tumor/metabolismo , Regulación hacia Arriba , Función Ventricular Izquierda/efectos de los fármacosRESUMEN
PURPOSE: This study tested if the protective anti-remodeling effect of GLP-1 agonist Exendin-4 after an acute myocardial infarction (MI) in rats involves inhibition of the Wnt1/ß-catenin signaling pathway. METHODS: Rats were divided into sham, sham + Exendin-4 (10 µg/day, i.p), MI, and MI + Exendin-4. MI was introduced to rats by permanent left anterior descending coronary artery (LAD) ligation. RESULTS: On day 7 post-infraction, MI rats showed LV dysfunction with higher serum levels of cardiac markers. Their remote myocardia showed increased mRNA and protein levels of collagen I/III with higher levels of reactive oxygen species (ROS) and inflammatory cytokines, as well as protein levels of Wnt1, phospho-Akt, transforming growth factor (TGF-ß1), Smad, phospho-Smad3, α-SMA, caspase-3, and Bax. They also showed higher protein levels of phospho-glycogen synthase kinase-3ß (p-GSK3ß), as well as total, phosphorylated, and nuclear ß-catenin with a concomitant decrease in the levels of cyclic adenosine monophosphate (cAMP), mRNA of manganese superoxide dismutase (MnSOD), and protein levels of Bcl-2, ß-arrestin-2, and protein phosphatase-2 (PP2A). Administration of Exendin-4 to MI rats reduced the infarct size and reversed the aforementioned signaling molecules without altering protein levels of TGF-1ß and Wnt1 or Akt activation. Interestingly, Exendin-4 increased mRNA levels of MnSOD, protein levels of ß-arrestin-2 and PP2A, and ß-catenin phosphorylation but reduced the phosphorylation of GSK3ß and Smad3, and total ß-catenin levels in the LV of control rats. CONCLUSION: Exendin-4 inhibits the remodeling in the remote myocardium of rats following acute MI by attenuating ß-catenin activation and activating ß-arrestin-2, PP2A, and GSK3ß. Graphical Abstract A graphical abstract that illustrates the mechanisms by which Exendin-4 inhibits cardiac remodeling in remote myocardium of left ventricle MI-induced rats. Mechanisms are assumed to occur in the cardiomyocytes and/or other resident cells such as fibroblast. Β-catenin activation and nuclear translocation are associated with increased synthesis of inflammatory cytokines and transforming growth factor ß-1 (TGF-ß1). GSK3ß is inhibited by phosphorylation at Ser9. Under normal conditions, ß-catenin is degraded in the cytoplasm by the active GSK3ß-dependent degradation complex (un-phosphorylated) which usually phosphorylates ß-catenin at Ser33/37/Thr41. After MI, TGF-ß1, and Wnt 1 levels are significantly increased, the overproduction of Wnt1 induces ß-catenin stabilization and nuclear translocation through increasing the phosphorylation of disheveled (DVL) protein which in turn phosphorylates and inhibits GSK3ß. TGF-ß1 stimulates the phosphorylation of Smad-3 and subsequent nuclear translocation to activate the transcription of collage 1/III and α-smooth muscle actin (α-SMA). Besides, TGF-ß1 stabilizes cytoplasmic ß-catenin levels indirectly by phosphorylation of Akt at Thr308-induced inhibition of GSK3ß by increasing phosphorylation of Ser9. Exendin-4, and possibly through G protein-coupled receptors (GPCRs), increases levels of cAMP and upregulates ß-arrestin-2 levels. Both can result in a positive inotropic effect. Besides, ß-arrestin-2 can stimulate PP2A to dephosphorylation Smad3 (inhibition) and GSK3ß (activation), thus reduces fibrosis and prevents the activation of ß-catenin and collagen deposition.
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Exenatida/farmacología , Glucógeno Sintasa Quinasa 3/efectos de los fármacos , Infarto del Miocardio/fisiopatología , Proteína Fosfatasa 2/efectos de los fármacos , beta Catenina/efectos de los fármacos , beta-Arrestinas/efectos de los fármacos , Animales , Hemodinámica/efectos de los fármacos , Masculino , Fosforilación , Ratas , Ratas Wistar , Proteína Wnt1/efectos de los fármacosRESUMEN
This study investigated whether the mechanism underlying the neurotoxic effects of cadmium chloride (CdCl2) in rats involves p66Shc. This study comprised an initial in vivo experiment followed by an in vitro experiment. For the in vivo experiment, male rats were orally administered saline (vehicle) or CdCl2 (0.05 mg/kg) for 30 days. Thereafter, spatial and retention memory of rats were tested and their hippocampi were used for biochemical and molecular analyses. For the in vitro experiment, control or p66Shc-deficient hippocampal cells were treated with CdCl2 (25 µM) in the presence or absence of SP600125, a c-Jun N-terminal kinase (JNK) inhibitor. Cadmium chloride impaired the spatial learning and retention memory of rats; depleted levels of glutathione and manganese superoxide dismutase; increased reactive oxygen species (ROS), tumor necrosis factor α, and interleukin 6; and induced nuclear factor kappa B activation. Cadmium chloride also decreased the number of pyramidal cells in the CA1 region and induced severe damage to the mitochondria and endoplasmic reticulum of cells in the hippocampi of rats. Moreover, CdCl2 increased the total unphosphorylated p66Shc, phosphorylated (Ser36) p66Shc, phosphorylated JNK, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, cytochrome c, and cleaved caspase-3. A dose-response increase in cell death, ROS, DNA damage, p66Shc, and NADPH oxidase was also observed in cultured hippocampal cells treated with CdCl2. Of note, all of these biochemical changes were attenuated by silencing p66Shc or inhibiting JNK with SP600125. In conclusion, CdCl2 induces hippocampal ROS generation and apoptosis by promoting the JNK-mediated activation of p66Shc.
Asunto(s)
Cloruro de Cadmio/toxicidad , Hipocampo/efectos de los fármacos , Proteínas Quinasas JNK Activadas por Mitógenos/metabolismo , NADPH Oxidasas/metabolismo , Síndromes de Neurotoxicidad/metabolismo , Proteína Transformadora 1 que Contiene Dominios de Homología 2 de Src/metabolismo , Animales , Apoptosis/efectos de los fármacos , Peso Corporal/efectos de los fármacos , Células Cultivadas , Daño del ADN , Hipocampo/metabolismo , Hipocampo/patología , Riñón/efectos de los fármacos , Hígado/efectos de los fármacos , Masculino , Aprendizaje por Laberinto/efectos de los fármacos , Memoria/efectos de los fármacos , Síndromes de Neurotoxicidad/genética , Síndromes de Neurotoxicidad/patología , Estrés Oxidativo/efectos de los fármacos , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , Proteína Transformadora 1 que Contiene Dominios de Homología 2 de Src/genéticaRESUMEN
The neuroprotective effect of Kaempferol against cadmium chloride (CdCl2) -induced neurotoxicity is well reported. The silent information regulator 1 (SIRT1) and poly (ADP-Ribose) polymerase-1 (PARP1) are two related cellular molecules that can negatively affect the activity of each other to promote or inhibit cell survival, respectively. It is still largely unknown if the neurotoxicity of CdCl2 or the neuroprotection of Kaempferol are mediated by modulating SIRT1 and/or PAPR1 activities. In this study, we tested the hypothesis that CdCl2-induced memory deficit and hippocampal damage are associated with downregulation/inhibition of SIRT1 and activation of PAPR1, an effect that can be reversed by co-treatment with Kaempferol. Rats (n = 12/group) were divided into 4 groups as control, control + Kaempferol (50 mg//kg), CdCl2 (0.5 mg/kg), and CdCl2 + Kaempferol. All treatments were administered orally for 30 days daily. As compared to control rats, CdCl2 reduced rat's final body weights (21.8%) and their food intake (30%), induced oxidative stress and apoptosis in their hippocampi, and impaired their short and long-term recognition memory functions. Besides, the hippocampi of CdCl2-treated rats had higher levels of TNF-α (197%), and IL-6 (190%) with a concomitant increase in nuclear activity and levels of NF-κB p65 (721% & 554%). Besides, they showed reduced nuclear activity (53%) and levels (74%) of SIRT1, higher nuclear activity and levels of PARP1 (292% & 138%), increased nuclear levels of p53 (870%), and higher acetylated levels of NF-κB p65 (513%), p53 (644%), PARP1 (696%), and FOXO-2 (149%). All these events were significantly reversed in the CdCl2 + Kaempferol-treated rats. Of note, Kaempferol also increased levels of MnSOD (73.5%), and GSH (40%), protein levels of Bcl-2 (350%), and nuclear activity (67%) and levels (46%) of SIRT1 in the hippocampi of the control rats. In conclusion, Kaempferol ameliorates CdCl2-induced memory deficits and hippocampal oxidative stress, inflammation, and apoptosis by increasing SIRT1 activity and inhibiting PARP1 activity.
Asunto(s)
Cloruro de Cadmio , Quempferoles , Animales , Hipocampo , Trastornos de la Memoria , Estrés Oxidativo , Poli(ADP-Ribosa) Polimerasa-1 , RatasRESUMEN
Sirt1 is a potent inhibitor of both poly(ADP-ribose) polymerases1 (PARP1) and NF-kB. This study investigated the cardioprotective effect of exendin-4 on cardiac function and remodeling in rats after an expreimentally-induced myocardial infarction (MI) and explored if this protection involves SIRT1/PARP1 axis. Rats were divided into five groups (n = 10/each): sham, sham + exendin-4 (25 nmol/kg/day i.p.), MI (induced by LAD occlusion), MI + exendin-4, and sham + exendin-4 + EX527 (5 mg/2×/week) (a SIRT1 inhibitor). All treatments were given for 6 weeks post the induction of MI. In sham-operated and MI-induced rats, exendin-4 significantly upregulated Bcl-2 levels, enhanced activity, mRNA, and levels of SIRT1, inhibited activity, mRNA, and levels of PARP1, and reduced ROS generation and PARP1 acetylation. In MI-treated rats, these effects were associated with improved cardiac architectures and LV function, reduced collagen deposition, and reduced mRNA and total levels of TNF-α and IL-6, as well as, the activation of NF-κB p65. In addition, exendin-4 inhibited the interaction of PARP1 with p300, TGF-ß1, Smad3, and NF-κB p65 and signficantly reduced mRNA and protein levels of collagen I/III and protein levels of MMP2/9. In conclusion, exendin-4 is a potent cardioprotective agent that prevents post-MI inflammation and cardiac remodeling by activating SIRT1-induced inhibition of PARP1.
Asunto(s)
Antiinflamatorios/farmacología , Exenatida/farmacología , Incretinas/farmacología , Infarto del Miocardio/tratamiento farmacológico , Miocitos Cardíacos/efectos de los fármacos , FN-kappa B/metabolismo , Poli(ADP-Ribosa) Polimerasa-1/metabolismo , Sirtuina 1/metabolismo , Función Ventricular Izquierda/efectos de los fármacos , Remodelación Ventricular/efectos de los fármacos , Acetilación , Animales , Apoptosis/efectos de los fármacos , Modelos Animales de Enfermedad , Fibrosis , Receptor del Péptido 1 Similar al Glucagón/agonistas , Receptor del Péptido 1 Similar al Glucagón/metabolismo , Masculino , Infarto del Miocardio/enzimología , Infarto del Miocardio/patología , Infarto del Miocardio/fisiopatología , Miocitos Cardíacos/enzimología , Miocitos Cardíacos/patología , Poli(ADP-Ribosa) Polimerasa-1/genética , Ratas Wistar , Transducción de Señal , Sirtuina 1/genéticaRESUMEN
Exendin-4, a glucagon-like peptide-1 receptor agonist, was shown to protect against cardiac ischaemia/reperfusion (I/R) injury by suppressing oxidative stress. p66 Shc, a pro-oxidant and an apoptotic protein, is activated in the infarcted left ventricles (LVs) after induction of I/R. This study investigated if the cardiac protective effect of Exendin-4 against I/R injury in rats involves inhibition of p66 Shc and to determine the underlying mechanisms behind this. Adult male rats (n = 12/group) were divided into four groups as a sham, a sham + Exendin-4, an I/R, and an I/R + Exendin-4. Exendin-4 was administered to rats 7 days before the induction of I/R. Ischaemia was induced by ligating the left anterior descending (LAD) coronary artery for 40 minutes followed by reperfusion for 10 minutes. The infarct myocardium was used for further analysis. Exendin-4 significantly reduced infarct area (by 62%), preserved LV function and lowered serum levels of LDH and CK-MB in I/R-induced rats. Also, it significantly reduced LV levels of ROS and MDA and protein levels of cytochrome-c and cleaved caspase-3 but significantly increased levels of glutathione (GSH) and manganese superoxide dismutase (MnSOD) in LVs of I/R rats indicating antioxidant and anti-apoptotic effects. Furthermore, it inhibited JNK and p66 Shc activation and downregulated protein levels of p66 Shc and NADPH oxidase with no effect on protein levels/activity of p53 and PKCßII. Of note, Exendin-4 also increased GSH and MnSOD in LVs of control rats. In conclusion, Exendin-4 cardioprotective effect in I/R hearts is mediated mainly by antioxidant effect and inhibition of JNK/P66 Shc/NADPH oxidase.
Asunto(s)
Antioxidantes/metabolismo , Exenatida/farmacología , MAP Quinasa Quinasa 4/metabolismo , Daño por Reperfusión Miocárdica/metabolismo , Daño por Reperfusión Miocárdica/prevención & control , NADP/metabolismo , Proteína Transformadora 1 que Contiene Dominios de Homología 2 de Src/metabolismo , Animales , Masculino , Daño por Reperfusión Miocárdica/patología , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-DawleyRESUMEN
This study investigated the protective effect of Kaempferol against CdCl2-induced hippocampal damage and memory deficit in rats and investigated if such effects involve modulating the activity of AMPK/PTEN/Akt/mTOR axis. Adult male rats (n = 12/group) were divided into control or CdCl2-treated rats received the vehicle of Kaempferol for consecutive 6 weeks. Also, hippocampal cells were treated with CdCl2 in the presence or absence of Kaempferol for 24 h with or without 1 h pre-incubation with compound C, an AMPK inhibitor or with bpV a PTEN inhibitor. Kaempferol improved the behavioral of CdCl2-treated rats, preserved hippocampus structure and reduced hippocampal levels of ROS and protein levels of Bax and cleaved caspase-3. In both control and CdCl2-treated rats, Kaempferol significantly increased hippocampal levels of GSH levels and protein levels of Nfr2, Bcl2 and synaptic proteins (SNAP-25, PSD-25, and synapsin). Concomitantly, it increased the activity of PTEN and AMPK and subsequently, decreased the activity of Akt and mTOR. In cultured cells, individual pharmacological inhibition of PTEN by bpv or AMPK of compound C (CC) partially prevented the stimulatory effect of Kaempferol on Akt/mTOR and its inhibitory effect on cell death whereas a combination of both inhibitors completely prevented this. Also, inhibition of PTEN alone completely abolished the inhibitory effect of Kaempferol by synaptic proteins, whereas inhibition of AMPK completely abolished its stimulatory effect of Nfr2. In conclusion, Kaempferol protects against CdCl2-induced memory deficits and hippocampal apoptosis by its antioxidant potential and inhibition of Akt/mTOR axis and requires the activation of PTEN and AMPK.
Asunto(s)
Apoptosis/efectos de los fármacos , Glutatión/metabolismo , Quempferoles/uso terapéutico , Trastornos de la Memoria/tratamiento farmacológico , Fármacos Neuroprotectores/uso terapéutico , Transducción de Señal/efectos de los fármacos , Proteínas Quinasas Activadas por AMP/metabolismo , Animales , Antioxidantes/uso terapéutico , Peso Corporal/efectos de los fármacos , Cloruro de Cadmio , Hipocampo/efectos de los fármacos , Hipocampo/patología , Masculino , Trastornos de la Memoria/inducido químicamente , Estrés Oxidativo/efectos de los fármacos , Fosfohidrolasa PTEN/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Ratas Wistar , Memoria Espacial/efectos de los fármacos , Serina-Treonina Quinasas TOR/metabolismoRESUMEN
This study investigated if the well-reported anti-tumor effects of resveratrol (RES) is mediated by modulation levels of galectin-3 (GAL-3), an anti-apoptotic lectin that is highly overexpressed in ovarian cancer cells. SKOV3 and OVCAR-3 OC cells were untreated or incubated with DMOS or increasing concentrations of RES (25, 50, 100 µM) for 72 hr. RES, in a dose-dependent manner and in both cell lines, induced cell death and inhibited cell migration and invasion It also downregulated Bcl-2 levels, increased cleaved caspase-3, and GAL-3 protein (but not mRNA) levels, suggesting increased breakdown. These effects were associated with reduced levels of p-NF-κB P65, p-IKKα/ß, and p-Akt, major targets of Gal-3. Further investigation showed that RES enhanced levels of miR-424-3p which is able to degrade GAL-3. Conclusion: Findings of this study suggest that RES induced apoptosis in cancerous cells is associated with increased levels of miR-424-3p and reduced levels of GAL-3. PRACTICAL APPLICATIONS: This study highlights a possible mechanism by which RES could enhance cell death in OC cells and enhances their sensitivity to cisplatin. RES apoptotic effect and enhancement of OC cells to chemotherapy were associated with decreased abundance of GAL-3, a common cell survival molecule that promotes tumorigenesis and increased transcription of miR-424-3p that has the ability to degrade cellular GAL-3. These findings add a possible new mechanism by which RES acts and opens a window for further research to understand its mechanism of action.
Asunto(s)
Caspasa 3/metabolismo , Movimiento Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Regulación hacia Abajo/efectos de los fármacos , Galectina 3/metabolismo , Neoplasias Ováricas/tratamiento farmacológico , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Resveratrol/farmacología , Femenino , Humanos , MicroARNsRESUMEN
This study compared the effect of low-fat diet (LFD) and high-fat diet rich in corn oil (HFD-CO) on left ventricular (LV) fibrosis in rats and examined their effect of angiotensin II (ANG II), JAK/STAT, and TGF-1ß/smad3 pathways. As compared to LFD which didn't affect any of the measured parameters, HFD-CO-induced type 2 diabetes phenotype and increased LV collagen synthesis. Mechanistically, it increased LV levels of ROS, ANG II, ACE, IL-6, s-IL-6Rα, TGF-ß1, Smad-3, and activities of JAK1/2 and STAT1/3. AG490, a JAK2 inhibitor, partially ameliorated these effect while Losartan, an AT1 inhibitor completely abolished collagen synthesis. However, with both treatments, levels of ANG II, IL-6, and s-IL-6Rα, and activity of JAK1/STAT3 remained high, all of which were normalized by co-administration of NAC or IL-6 neutralizing antibody. In conclusion: HFD-CO enhances LV collage synthesis by activation of JAK1/STAT3/ANG II/TGF-1ß/smad3 pathway. PRACTICAL APPLICATIONS: We report that chronic consumption of a high-fat diet rich in corn oil (HFD-CO) induces diabetes mellitus phenotype 2 associated with left ventricular (LV) cardiac fibrosis in rats. The findings of this study show that HFD-CO, and through the increasing generation of ROS and IL-6 levels and shedding, could activate LV JAK1/2-STAT1/3 and renin-angiotensin system (RAS) signaling pathways, thus creating a positive feedback between the two which ultimately leads to activation of TGF-1ß/Smad3 fibrotic pathway. Herein, we also report a beneficial effect of the antioxidant, NAC, or IL-6 neutralizing antibody in preventing such adverse effects of such HFD-CO. However, this presents a warning message to the current sudden increase in idiopathic cardiac disorders, especially with the big shift in our diets toward n-6 PUFA.
Asunto(s)
Aceite de Maíz/efectos adversos , Dieta Alta en Grasa/efectos adversos , Fibrosis/metabolismo , Cardiopatías/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Angiotensina II/genética , Angiotensina II/metabolismo , Animales , Aceite de Maíz/metabolismo , Fibrosis/etiología , Fibrosis/genética , Cardiopatías/etiología , Cardiopatías/genética , Ventrículos Cardíacos/metabolismo , Humanos , Interleucina-6/genética , Interleucina-6/metabolismo , Janus Quinasa 2/genética , Janus Quinasa 2/metabolismo , Masculino , Ratas , Ratas Wistar , Factor de Transcripción STAT3/genética , Factor de Transcripción STAT3/metabolismo , Transducción de Señal , Proteína smad3/genética , Proteína smad3/metabolismo , Factor de Crecimiento Transformador beta1/genética , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
This study investigates the effect of chronic consumption of a high-fat diet rich in corn oil (CO-HFD) on atrial cells ultrastructure, antioxidant levels and markers of intrinsic cell death of both control and type 1 diabetes mellitus (T1DM)-induced rats. Adult male rats (10 rats/group) were divided into four groups: control fed standard diet (STD) (3.82 kcal/g, 9.4% fat), CO-HFD (5.4 kcal/g, 40% fat), T1DM fed STD, and T1DM + CO-HFD. CO-HFD and T1DM alone or in combination impaired systolic and diastolic functions of rats and significantly reduced levels of GSH and the activity of SOD, enhanced lipid peroxidation, increased protein levels of P53, Bax, cleaved caspase-3, and ANF and decreased levels of Bcl-2 in their atria. Concomitantly, atrial cells exhibited fragmentation of the myofibrils, disorganized mitochondria, decreased number of atrionatriuretic factor (ANF) granules, and loss of gap junctions accompanied by changes in capillary walls. Among all treatments, the severity of all these findings was more severe in T1DM and most profound in the atria of T1DM + CO-HFD. In conclusion, chronic consumption of CO-HFD by T1DM-induced rats elicits significant biochemical and ultrastructural damage to rat atrial cells accompanied by elevated oxidative stress and mitochondria-mediated cell death.
Asunto(s)
Muerte Celular/efectos de los fármacos , Aceite de Maíz/efectos adversos , Diabetes Mellitus Tipo 1/patología , Dieta Alta en Grasa/efectos adversos , Grasas de la Dieta/farmacología , Atrios Cardíacos/efectos de los fármacos , Atrios Cardíacos/ultraestructura , Animales , Antioxidantes/metabolismo , Aceite de Maíz/administración & dosificación , Diabetes Mellitus Experimental/complicaciones , Diabetes Mellitus Experimental/patología , Diabetes Mellitus Experimental/fisiopatología , Diabetes Mellitus Tipo 1/complicaciones , Diabetes Mellitus Tipo 1/fisiopatología , Angiopatías Diabéticas/etiología , Angiopatías Diabéticas/patología , Angiopatías Diabéticas/fisiopatología , Conducta Alimentaria/fisiología , Atrios Cardíacos/metabolismo , Atrios Cardíacos/patología , Hemodinámica/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Masculino , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Wistar , Transducción de Señal/efectos de los fármacosRESUMEN
This study investigated the effect of acylated synthetic ghrelin (AG) on the survival and proliferation of human chemosensitive ovarian cancer cells (A2780) and explored some mechanisms of action with a focus on the p53 apoptotic pathway and PI3K/Akt and NF-κB survival pathways. Human A2780 ovarian cancer cells were cultured with or without AG treatment in the presence or absence of cisplatin. In some cases, cisplatin+AG-treated cells were pre-incubated either with [D-Lys3]-GHRP-6, a ghrelin receptor antagonist, or with LY294002, a PI3K inhibitor. mRNA of ghrelin receptors(GHS-R1a and GHS-R1b), as well as, protein levels of GHS-R1a, were expressed abundantly in A2780 cells. AG treatment did not affect the mRNA and protein levels of GHS-R1a and GHS-R1b in both control and Cis-treated cells. However, while AG treatment had no effect on control cell viability, it significantly increased cell viability and proliferation and inhibited cell death in Cis-treated cells. In both control and Cis-treated cells, AG treatment significantly increased PI3K/Akt/mTOR signaling and enhanced the nuclear accumulation of NF-κB. Concomitantly, in both control and Cis-treated cells, AG significantly lowered the protein levels of p53, p-p53 (Ser16), PUMA, cytochrome C, and cleaved caspase-3. Interestingly, pre-incubating the cells with either [D-Lys3]-GHRP-6 or LY294002 completely abolished the above-mentioned effect of AG in both control and Cis-treated cells. In conclusion, the findings of this study show that AG promotes cell survival of the OC cells and renders them resistat to Cis therapy, an effect that is mediated by the activation of PI3K/Akt/mTOR and activation of NF-κB, and requires GHS-R1a.
Asunto(s)
Cisplatino/farmacología , Resistencia a Antineoplásicos/efectos de los fármacos , Ghrelina/farmacología , Neoplasias Ováricas/patología , Fosfatidilinositol 3-Quinasas/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Serina-Treonina Quinasas TOR/metabolismo , Acilación , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Femenino , Humanos , FN-kappa B/metabolismo , Proteínas de Neoplasias/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Receptores de Ghrelina/genética , Receptores de Ghrelina/metabolismo , Transducción de Señal/efectos de los fármacosRESUMEN
Autophagy promotes cell survival or induces apoptosis in cancer cells. While SIRT1 and AMPK induce autophagy in both normal and cancer cells, Akt and mTOR can inhibit it. Calycosin, a methoxyisoflavone, protects against several types of solid tumours including colorectal cancer. However, the mechanisms behind the antitumour effect of Calycosin remain largely unknown. This study investigates if autophagy mediates the anti-tumourigenesis effect afforded by Calycosin and examines if this effect involves activation of SIRT1 and/or AMPK. Human colorectal (HT29) carcinoma cells were cultured under normal conditions with Calycosin (50 µmol/L) in the presence or absence of chloroquine (10 µmol/L), EX-527 (100 nmol/L, SIRT1 inhibitor), or IGF-1 (100 ng/mL, Akt/mTOR activator) for 48 hours. Calycosin inhibited cell growth, proliferation and invasion and increased protein levels of Beclin-1 and LC3II, markers of autophagy. It significantly increased protein levels of cleaved caspase-3, Bax, and SIRT1, and activity of AMPK and reduced those of Bcl-2. These effects were parallel with concomitant reduction in protein levels p-src, integrin-ß1 and Cyclin-D1 and activities of Akt and mTOR. Inhibition of autophagy by CQ reversed all these effects except cell invasion. Interestingly, co-incubating the cells with either EX-527 or IGF-1 completely prevented Calycosin-induced autophagy and all other associated effects and increased cell invasion. Also, blockade of SIRT-1 prevented the activation of AMPK, Akt, and mTOR, suggesting it to be an upstream regulator of these markers. In conclusion, Calycosin stimulates CRC cell apoptosis and inhibits their invasion by acting as SIRT1 activator which induces activation of AMPK-induced inhibition of Akt/mTOR axis.
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Proteínas Quinasas Activadas por AMP/metabolismo , Adenocarcinoma/patología , Apoptosis/efectos de los fármacos , Isoflavonas/farmacología , Proteínas Proto-Oncogénicas c-akt/antagonistas & inhibidores , Sirtuina 1/metabolismo , Serina-Treonina Quinasas TOR/antagonistas & inhibidores , Caspasa 3/metabolismo , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Células HT29 , Humanos , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Transducción de Señal/efectos de los fármacos , Proteína X Asociada a bcl-2/metabolismoRESUMEN
Obesity is a modifiable risk factor for the development and progression of kidney disease. Obesity may harm kidneys in individuals without hypertension, diabetes, or pre-existing renal disease. Ginger, Zingiber officinale, has many beneficial pharmaceutical benefits. This study aimed to evaluate the Zingiber officinale protective effect against obesity complications which induced by high fat diet and caused renal dysfunctions. The study period was two months, and the experimental animals' groups were four, 80 Wistar rats were appropriated similarly 20 animals/group: control group; ginger extract group (GE); high-fat diet (HFD); and GE+HFD group. Body and fat weight, creatinine, leptin, TNF-α, total antioxidants, renal histopathological and ultrastructure were investigated. Rats in group of HFD showed a significant increase (P<0.05) in the body and fat weights, creatinine, leptin and TNF-α, and significant decrease (P<0.05) in total antioxidants (TAS). Ginger administration significantly showed the protective restoring the altered parameters. Furthermore, rats co-treated with ginger extract improved the histopathological and ultrastructural renal injury induced by obesity. The study concluded that the ginger extract used could suppress and decrease the renal damage induced by high-fat diet as it possesses potential medicinal values.
La obesidad es un factor de riesgo modificable para el desarrollo y la progresión de la enfermedad renal. La obesidad puede dañar los riñones en personas sin hipertensión, diabetes o enfermedad renal preexistente. El jengibre, Zingiber officinale, tiene muchos beneficios farmacéuticos. Este estudio tuvo como objetivo evaluar el efecto protector de Zingiber officinale en las complicaciones de la obesidad inducida por una dieta alta en grasas y las enfermedad renal. El período de estudio fue de dos meses, y los grupos de animales experimentales fueron cuatro, se asignaron 80 ratas Wistar de manera similar, 20 animales por grupo: grupo de control; grupo de extracto de jengibre (GE); dieta alta en grasas (DAG); y el grupo GE + DAG. Se evaluó el peso corporal y la grasa, creatinina, leptina, TNF-α, antioxidantes totales, histopatología renal y ultraestructura. Las ratas en el grupo de DAG mostraron un aumento significativo (P<0,05) en el peso corporal y de grasa, creatinina, leptina y TNF-a, y una disminución significativa (P<0,05) en los antioxidantes totales. La administración de jengibre mostró una protección significativa restaurando los parámetros alterados. Además, las ratas tratadas conjuntamente con extracto de jengibre mejoraron la lesión renal histopatológica y ultraestructural inducida por la obesidad. El estudio concluyó que el extracto de jengibre podría suprimir y disminuir el daño renal inducido por la dieta alta en grasas, ya que posee potenciales valores medicinales.
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Animales , Ratas , Extractos Vegetales/farmacología , Zingiber officinale/química , Dieta Alta en Grasa/efectos adversos , Enfermedades Renales/tratamiento farmacológico , Obesidad/complicaciones , Peso Corporal , Factor de Necrosis Tumoral alfa/análisis , Ratas Sprague-Dawley , Creatinina/análisis , Leptina/análisis , Microscopía Electrónica de Transmisión , Riñón/patología , Enfermedades Renales/patologíaRESUMEN
This study investigated if JAK/STAT signaling pathway mediates doxorubicin (DOX)-induced cell death and fibrosis in left ventricles (LVs) of rats and examined if acylated ghrelin affords protection by modulating this pathway. Male rats (120 ± 5 g) were divided into 6 groups (10 rats each) as follows: control; control + AG (10 ng/kg, s.c.); DOX (an accumulative dose 15 mg/kg, i.p.); DOX + AG, DOX + AG + AG490, a JAK2 inhibitor (5 mg/kg, i.p.); and DOX + AG + [D-Lys3]-GHRP-6; an AG receptor antagonist (3.75 mg/kg, i.p.). All treatments were carried out for 35 days. In rats' LVs, DOX significantly impaired the systolic and diastolic functions, enhanced levels of ROS and MDA, reduced levels of GSH and Bcl-2, and increased mRNA and protein levels of collagen I/III and TGF-ß and cleaved caspase-3. In addition, although DOX did not affect JAK1 or JAK2 activity, it significantly increased protein levels of IL-6, decreased STAT3 and p-STAT3 (Tyr701&Ser727), and increased STAT1 and p-STAT1 (Tyr701&Ser727) levels, with a concomitant decrease in ERK1/2 activity and an increase in P38 activity. However, without affecting IL-6 and JAK1/2, AG reversed all of the observed alterations with a significant increase in the levels and activities of JAK2. Similar effects of AG were also seen in control rats. Interestingly, all the beneficial effects afforded by AG were abolished by AG490 and AG + [D-Lys3]-GHRP-6. In conclusion, DOX-induced cardiac toxicity involves stimulation of IL-6, P38, and STAT1 signaling levels whereas the protective effect afforded by AG involves the activation of ERK1/2 and JAK2/STAT3 and inhibition of STAT1.
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Antineoplásicos , Cardiotónicos/farmacología , Cardiotónicos/uso terapéutico , Cardiotoxicidad/tratamiento farmacológico , Doxorrubicina , Ghrelina/farmacología , Ghrelina/uso terapéutico , Acetilación , Animales , Cardiotoxicidad/metabolismo , Cardiotoxicidad/patología , Cardiotoxicidad/fisiopatología , Muerte Celular/efectos de los fármacos , Colágeno/genética , Colágeno/metabolismo , Fibrosis , Ghrelina/sangre , Glutatión/metabolismo , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/metabolismo , Ventrículos Cardíacos/patología , Ventrículos Cardíacos/fisiopatología , Interleucina-6/genética , Interleucina-6/metabolismo , Janus Quinasa 2/metabolismo , Masculino , Ratas Wistar , Factor de Transcripción STAT1/metabolismo , Factor de Transcripción STAT3/metabolismo , Transducción de Señal/efectos de los fármacos , Factor de Crecimiento Transformador beta1/genética , Factor de Crecimiento Transformador beta1/metabolismoRESUMEN
This study investigated if calcineurin/nuclear factor of activated T cells (NFAT) axis mediates the cardiac apoptosis in rats with type 1 diabetes mellitus (T1DM)-induced rats or administered chronically high-fat diet rich in corn oil (CO-HFD). Also, it investigated the impact of chronic administration of CO-HFD on Fas/Fas ligand (Fas/FasL)-induced apoptosis in the hearts of T1DM-induced rats. Adult male Wistar rats (140-160 g) were classified as control: (10% fat) CO-HFD: (40% fat), T1DM, and T1DMâ¯+â¯CO-HFD (n=20/each). In vitro, cardiomyocytes were cultured in either low glucose (LG) or high glucose (HG) media in the presence or absence of linoleic acid (LA) and other inhibitors. Compared to the control, increased reactive oxygen species (ROS), protein levels of cytochrome C, cleaved caspase-8 and caspase-3, myocardial damage and impeded left ventricular (LV) function were observed in the hearts of all treated groups and maximally in T1DMâ¯+â¯CO-HFD-treated rats. mRNA of all NFAT members (NFAT1-4) were not affected by any treatment. CO-HFD or LA significantly up-regulated Fas levels in both LVs and cultured cardiomyocytes in a ROS dependent mechanism and independent of modulating intracellular Ca2+ levels or calcineurin activity. T1DM or hyperglycemia significant up-regulated mRNA and protein levels of Fas and FasL by activating Ca2+/calcineurin/NFAT-4 axis. Furthermore, Fas/FasL cell death induced by recombinant FasL (rFasL) or HG media was enhanced by pre-incubating the cells with LA. In conclusion, activation of the Ca2+/calcineurin/NFAT4 axis is indispensable for hyperglycemia-induced Fas/FasL cell death in the cardiomyocytes and CO-HFD sensitizes this by up-regulation of Fas.
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Diabetes Mellitus Experimental/patología , Dieta Alta en Grasa/efectos adversos , Miocardio/metabolismo , Miocardio/patología , Animales , Calcineurina/metabolismo , Muerte Celular , Células Cultivadas , Aceite de Maíz/efectos adversos , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/mortalidad , Diabetes Mellitus Tipo 1/etiología , Diabetes Mellitus Tipo 1/metabolismo , Diabetes Mellitus Tipo 1/mortalidad , Diabetes Mellitus Tipo 1/patología , Proteína Ligando Fas/genética , Proteína Ligando Fas/metabolismo , Regulación de la Expresión Génica , Hiperglucemia/metabolismo , Hiperglucemia/patología , Ácido Linoleico/farmacología , Masculino , Miocitos Cardíacos/efectos de los fármacos , Miocitos Cardíacos/metabolismo , Miocitos Cardíacos/patología , Factores de Transcripción NFATC/genética , Factores de Transcripción NFATC/metabolismo , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , Receptor fas/genética , Receptor fas/metabolismoRESUMEN
CONTEXT: Mechanisms by which ghrelin affords its cardioprotection in mammals remained unclear. OBJECTIVE: To examine if ghrelin confers cardio-protection during cardiac remodelling post-MI by modulating the RAF-1-MEK1/2-ERK1/2 signalling pathway. MATERIALS AND METHODS: Rats were divided into control, sham, sham + ghrelin, myocardial infarction (MI), and MI + ghrelin groups. Ghrelin (100 µg/kg) was administered for 21 days, starting one-day post-MI. RESULTS: Ghrelin enhanced cardiac contractility and the activities of antioxidant enzymes, lowered serum levels of enzyme markers of cardiac dysfunction, and lowered inflammatory mediator levels. Ghrelin increased levels of phospho-Raf-1 (Ser338), phospho-MEK1/2 (Ser217/221), phospho-ERK1/2 (Thr202/Tyr204), and of their downstream target p-BAD (Ser112) and inhibited the cleavage of caspase-3. Concomitantly, ghrelin prevented the increases in the levels of fibrotic markers, including α-smooth muscle actin (α-SMA), metalloproteinase-9 (MPP-9), and type III collagen. CONCLUSION: Post-MI in rats, ghrelin stimulated Raf-1-MEK1/2-ERK1/2-BAD signalling in the LV infarct areas, accounting for its anti-apoptotic effect, enhancing cardiac function, and inhibiting cardiac fibrosis during cardiac remodelling.
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Apoptosis/efectos de los fármacos , Ghrelina/farmacología , Sistema de Señalización de MAP Quinasas/efectos de los fármacos , Infarto del Miocardio/patología , Miocardio/patología , Remodelación Ventricular/efectos de los fármacos , Animales , Biomarcadores/metabolismo , Citoprotección/efectos de los fármacos , Modelos Animales de Enfermedad , Fibrosis , Hemodinámica/efectos de los fármacos , MAP Quinasa Quinasa 1/metabolismo , MAP Quinasa Quinasa 2/metabolismo , Masculino , Proteína Quinasa 1 Activada por Mitógenos/metabolismo , Proteína Quinasa 3 Activada por Mitógenos/metabolismo , Infarto del Miocardio/metabolismo , Infarto del Miocardio/fisiopatología , Miocardio/enzimología , Estrés Oxidativo/efectos de los fármacos , Ratas , Ratas Sprague-Dawley , Quinasas raf/metabolismoRESUMEN
NAD(P)H dependent oxidase derived-reactive oxygen species (ROS) due to activation of the renin-angiotensin-aldosterone system (RAAS) in blood vessels postmyocardial infarction MI or during the HF leads to endothelium dysfunction and enhanced apoptosis. Acylated ghrelin (AG) is a well-reported cardioprotective and antiapoptotic agent for the heart. AG receptors are widely distributed in most of blood vessels, suggesting a role in the regulation of endothelial function and survival. This study investigated if AG can protect aorta of rats' postmyocardial infarction (MI)-induced damage and endothelial dysfunction. Adult male rats were divided into four groups of (1) Sham, (2) Sham + AG, (3) MI, and (4) MI + AG. Vehicle (normal saline) or AG (100 µ/kg) was administered to rats for 21 consecutive days, after which, numerous biochemical markers were detected by blot. Both histological and electron microscope studies were carried on aortic samples from MI-induced rats. AG increased protein levels of both total and phosphorylated forms of endothelial nitric oxide synthase (eNOS and p-eNOS, respectively). Only in MI-treated rats, AG prevented the decreases in the levels of reduced glutathione (GSH) and superoxide dismutase (SOD) and lowered levels of malondialdehyde (MDA) and glutathione disulfide (GSSG). Concomitantly, it lowered the increased protein levels of angiotensin-converting enzyme (ACE), p22phox and cleaved caspase-3 and prevented the aorta histological and ultrustructural abnormalities induced by MI.
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Aorta/efectos de los fármacos , Activación Enzimática/efectos de los fármacos , Ghrelina/farmacología , Infarto del Miocardio/patología , Estrés Oxidativo/efectos de los fármacos , Acetilación , Animales , Aorta/patología , Aorta/ultraestructura , Masculino , NADPH Oxidasas/metabolismo , Óxido Nítrico Sintasa de Tipo III/metabolismo , Ratas , Ratas Sprague-Dawley , Renina/metabolismoRESUMEN
Ghrelin is a novel growth hormone-releasing peptide administered to treat myocardial infarction (MI). However, the underlying mechanism of its protective effects against MI remains unclear. A total of sixty healthy Sprague Dawley male rats were included. The first one is the sham-operated control group were the rats that underwent the same surgical used to induce MI but without tying the left anterior descending coronary artery (LAD) and received normal saline (0.5 ml) as vehicle; the second MI model group were rats with LAD ligation and received normal saline (0. 5 ml) and the third one is MI+ghrelin group were rats that were exposed to surgery to induce MI but received ghrelin (100 µ/kg, orally, 2x/day). At the end of the experiment after 21 days post-MI, rats were sacrificed and processed for ultrastructural demonstration. Our experiment showed that ghrelin inhibited cardiomyocyte apoptosis. Concomitant administration of ghrelin with MI treated rats of this study appeared to show a considerable protection of the atrial tissues. This study revealed that the sarcoplasm was occupied by normal myofibrils with clear striations and others appeared with minor disruption. Normal distribution of atrionatriuretic factor (ANF) granules and well preserved mitochondrial integrity (preserved cristae, normal size and shape), nucleus chromatin arrangement and striated pattern of clear bands (Z and H) compared to the MI group. Intact intercalated disc with clear identification of fully formed fascia adherence and desmosomes with a reconstruction of gap junction (nexus) was also noticed. Atrial myocytes after myocardial infarction is often associated with subsequent heart failure, which could lead to a fatal outcome. In a rat model of experimental myocardial infarction, peripheral ghrelin administration attenuated myocyte dysfunction, well-preserved desmosome, adherent and gap junction of the intercalated disc and normally distributed ANF granules.
La grelina es un nuevo péptido liberador de hormona de crecimiento administrado para tratar el infarto de miocardio (IM). Sin embargo, el mecanismo subyacente de sus efectos protectores contra el IM aún no se conocen. Se incluyeron un total de 60 ratas macho Sprague Dawley saludables. En el grupo control se incluyeron ratas que fueron sometidas a una cirugía utilizada para inducir el IM, pero sin ligar la arteria coronaria descendente anterior izquierda (ACDAI) y recibieron suero fisiológico normal (0,5 ml) como vehículo; el segundo grupo modelo de IM fueron ratas con ligadura de ACDAI y recibieron suero fisiológico normal (0,5 ml); el tercer grupo estuvo formado por ratas con IM + grelina, expuestas a la cirugía para inducir IM pero luego recibieron grelina (100 m/kg, oralmente, 2x/día). Al final del experimento, 21 días después del infarto de miocardio, los animales fueron sacrificados y procesados para el estudio ultraestructural. Nuestro experimento mostró que la grelina inhibe la apoptosis de los cardiomiocitos. La administración concomitante de grelina en ratas con IM parece indicar una protección considerable de los tejidos atriales. Además, el estudio reveló que el sarcoplasma estaba ocupado por miofibrillas normales con estriaciones claras y otras con una alteración menor. Se encontró una distribución normal de los gránulos del factor natriurético atrial (FNA) e integridad mitocondrial bien conservada (crestas conservadas, tamaño y forma normales), disposición de la cromatina del núcleo y patrón estriado de bandas claras (Z y H) en comparación con el grupo IM. También se observó un disco intercalado intacto con una clara identificación de la adherencia de la fascia completamente formada y desmosomas con una reconstrucción de la unión gap (nexo). Los miocitos atriales, después de un infarto de miocardio, a menudo se asocian con insuficiencia cardíaca posterior, que podría conducir a un desenlace fatal. En un modelo de rata de infarto de miocardio experimental, la administración de grelina periférica atenuó la disfunción de miocitos, con conservación del desmosoma, adherencia y unión de la brecha del disco intercalado y una distribución normal de los los gránulos de FNA.
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Animales , Masculino , Ratas , Factor Natriurético Atrial/metabolismo , Hormonas Peptídicas/metabolismo , Infarto del Miocardio/metabolismo , Factor Natriurético Atrial/ultraestructura , Ratas Sprague-Dawley , Microscopía Electrónica de Transmisión , Modelos Animales de Enfermedad , GhrelinaRESUMEN
This study investigated the effect of ghrelin on cardiomyocytes function, apoptosis and ultra-structural alterations of remote myocardium of the left ventricle (LV) of rats, 21 days post myocardial infarction (MI). Rats were divided into 4 groups as a control, a sham-operated rats, a sham-operated+ghrelin, an MIâ¯+â¯vehicle and an MIâ¯+â¯ghrelin-treated rats. MI was induced by LAD ligation and then rats were recievd a concomitant doe of either normal saline as a vehicle or treated with ghrelin (100⯵g/kg S.C., 2x/day) for 21 consecutive days. Ghrelin enhanced myocardial contractility in control rats and reversed the decreases in myocardial contractility and the increases in the serum levels of CK-MB and LDH in MI-induced rats. Additionally, it inhibited the increases in levels of Bax and cleaved caspase 3 and increased those for Bcl-2 in the remote myocardium of rat's LV, post-MI. At ultra-structural level, while ghrelin has no adverse effects on LV myocardium obtained from control or sham-treated rats, ghrelin post-administration to MI-induced rats reduced vascular formation, restored normal microfilaments appearance and organization, preserved mitochondria structure, and prevented mitochondrial swelling, collagen deposition and number of ghost bodies in the remote areas of their LV. Concomitantly, in remote myocardium of MI-induced rats, ghrelin enhanced endoplasmic reticulum intracellular organelles count, decreased number of atrophied nuclei and phagocytes, diminished the irregularity in the nuclear membranes and inhibited chromatin condensation. In conclusion, in addition to the physiological, biochemical and molecular evidence provided, this is the first study that confirms the anti-apoptotic effect of ghrelin in the remote myocardium of the LV during late MI at the level of ultra-structural changes.
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Apoptosis , Ghrelina/administración & dosificación , Ghrelina/uso terapéutico , Infarto del Miocardio/tratamiento farmacológico , Miocardio/patología , Miocardio/ultraestructura , Animales , Apoptosis/efectos de los fármacos , Caspasa 3/metabolismo , Ghrelina/farmacología , Pruebas de Función Cardíaca , Ventrículos Cardíacos/efectos de los fármacos , Ventrículos Cardíacos/patología , Ventrículos Cardíacos/fisiopatología , Ventrículos Cardíacos/ultraestructura , Hemodinámica/efectos de los fármacos , Masculino , Infarto del Miocardio/sangre , Infarto del Miocardio/fisiopatología , Miocardio/enzimología , Ratas Sprague-Dawley , Proteína X Asociada a bcl-2/metabolismoRESUMEN
The molecular mechanisms through which ghrelin exerts its cardioprotective effects during cardiac remodeling post-myocardial infarction (MI) are poorly understood. The aim of this study was to investigate whether the cardioprotection mechanisms are mediated by modulation of JAK/STAT signaling and what triggers this modulation. Rats were divided into six groups (n = 12/group): control, sham, sham + ghrelin (100 µg/kg, s.c., daily, starting 1 day post-MI), MI, MI+ ghrelin, and MI+ ghrelin+ AG490, a potent JAK2 inhibitor (5 mg/kg, i.p., daily). All treatments were administered for 3 weeks. Administration of ghrelin to MI rats improved left ventricle (LV) architecture and restored cardiac contraction. In remote non-infarcted areas of MI rats, ghrelin reduced cardiac inflammation and lipid peroxidation and enhanced antioxidant enzymatic activity. In addition, independent of the growth factor/insulin growth factor-1 (GF/IGF-1) axis, ghrelin significantly increased the phosphorylation of JAK2 and Tyr702 and Ser727 residues of STAT3 and inhibited the phosphorylation of JAK1 and Tyr701 and Ser727 residues of STAT1, simultaneously increasing the expression of BCL-2 and decreasing in the expression of BAX, cleaved CASP3, and FAS. This effect coincided with decreased expression of SOCS3. All these beneficial effects of ghrelin, except its inhibitory action on IL-6 expression, were partially and significantly abolished by the co-administration of AG490. In conclusion, the cardioprotective effect of ghrelin against MI-induced LV injury is exerted via activation of JAK2/STAT3 signaling and inhibition of STAT1 signaling. These effects were independent of the GF/IGF-1 axis and could be partially mediated via inhibition of cardiac IL-6.