RESUMEN
AIMS: Weightlessness exposure conduces to substantial vascular remodeling, mechanisms behind which remain unclear. Acid sphingomyelinase (ASM) catalyzed ceramide (Cer) generation accounts for multiple vascular disorders, so the role of it in adjustment of cerebral artery (CA) and small mesenteric artery (MA) was investigated in simulated weightless rats. MAIN METHODS: Rats were hindlimb unloaded tail suspended (HU) to simulate the effect of weightlessness. Arterial morphology was examined by hematoxylin-eosin staining. Cer abundance was measured by immunohistochemistry. Western blotting was used to detect protein content. Apoptosis was detected by transferase-mediated dUTP nick end labeling. KEY FINDINGS: During 4 weeks of tail suspension, intima-media thickness (IMT) and media cross section area (CSA) were increased gradually in CA but decreased gradually in MA (P < 0.05). Correspondingly, the apoptosis and proliferation of vascular smooth muscle cells were reduced and enhanced respectively in CA (P < 0.05), while promoted and restrained in MA (P < 0.05). As compared to control, both ASM protein expression and Cer content were lowered in CA and elevated in MA of HU rats (P < 0.05). Permeable Cer incubation reversed the change of apoptosis and proliferation in CA of HU rats, while ASM inhibition recapitulated it in control rats. On the contrary, ASM inhibitors restored the alteration of apoptosis and proliferation in MA of HU. SIGNIFICANCE: The results suggest that by controlling the balance between apoptosis and proliferation, ASM/Cer exerts an important role in structural adaptation of CA and MA to simulated weightlessness.
Asunto(s)
Ceramidas/metabolismo , Arterias Cerebrales/metabolismo , Suspensión Trasera , Arterias Mesentéricas/metabolismo , Esfingomielina Fosfodiesterasa/metabolismo , Ingravidez , Animales , Apoptosis , Proliferación Celular , RatasRESUMEN
Noise-induced hearing loss (NIHL) relates closely to auditory cortex (AC) injury, so countermeasures aiming at the AC recovery would be of benefit. In this work, the effect of hyperbaric oxygen treatment on NIHL was elucidated, which was imposed on mice before (HBOP), during (HBOD) or after (HBOA) noise exposure. Morphology of neurons was assayed by hematoxylin-eosin or Nissl staining. Ceramide (Cer) level was measured through immunohistochemistry analysis. Apoptotic neurons were counted using transferase-mediated dUTP nick end labeling (TUNEL) staining. We demonstrated that the intense, broad band noise raised the threshold of auditory brainstem response, evoked neuronal degeneration or apoptosis and triggered the Cer accumulation in AC, all of which were restored significantly by HBOP, but not HBOD or HBOA. Cer over-generation reversed the advantages of HBOP significantly, while its curtailment recapitulated the effect. Next, noise exposure raised the superoxide or malondialdehyde (MDA) production which was blocked by HBOP or Cer repression. Oxidative control not only attenuated the hearing loss or neurodegeneration but, in turn, reduced the Cer formation significantly. In summary, mutual regulation between Cer and oxidative stress underlies the HBOP's curative effect on hearing loss and neuronal damage in noise-exposed mice.
Asunto(s)
Corteza Auditiva , Ceramidas/metabolismo , Pérdida Auditiva , Oxigenoterapia Hiperbárica , Ruido/efectos adversos , Animales , Corteza Auditiva/patología , Corteza Auditiva/fisiopatología , Pérdida Auditiva/metabolismo , Pérdida Auditiva/patología , Pérdida Auditiva/fisiopatología , Pérdida Auditiva/terapia , Masculino , RatonesRESUMEN
Noise-induced structural and functional disorder of the liver has been realized, but the underlying mechanism remains to be characterized, which has limited the introduction of precautious measures. Over-activation of acid sphingomyelinase (ASM)/ceramide (Cer) pathway takes centre stage in hepatocyte injury entailed by various stimulus. We aimed to investigate whether it mediated the noise elicited liver disorder on infrastructure, lipid metabolism, apoptosis, and oxidative stress. Mice were exposed to broad band noise (20-20k Hz, 90-110 dB) for 1, 3, 5 or 7 days by 3 hr/d. Doxepin hydrochloride (DOX), an ASM inhibitor was given by 5 mg/kg/d gavage. We showed that 5 or 7 days intense, broad band noise exposure caused significant infrastructure derangement and lipid droplets storage in hepatocytes. The content of cholesterol, free fatty acids or triglyceride was increased significantly in liver tissue upon noise stimulation. Moreover, the noise promoted apoptosis and superoxide generation in hepatocytes significantly, enhancing activity of aspartate aminotransferase (AST) or alanine amino transferase (ALT) in serum. Acid sphingomyelinase activity and Cer generation in liver tissue were elevated by noise exposure, which was normalized with DOX administrated. Accordingly, DOX alleviated steatosis, apoptosis, oxidative stress and enzymatic change in hepatocytes or serum of noise exposed mice substantially. In summary, our results suggest the ASM/Cer pathway contributes to the broad band noise elicited liver damage in mice.
Asunto(s)
Hepatopatías/enzimología , Hepatopatías/etiología , Ruido/efectos adversos , Esfingomielina Fosfodiesterasa/metabolismo , Alanina Transaminasa/metabolismo , Animales , Apoptosis/efectos de los fármacos , Aspartato Aminotransferasas/metabolismo , Ceramidas/metabolismo , Doxepina/farmacología , Fibrosis , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Hepatocitos/patología , Gotas Lipídicas/efectos de los fármacos , Gotas Lipídicas/metabolismo , Hepatopatías/metabolismo , Hepatopatías/patología , Masculino , Ratones , Estrés Oxidativo/efectos de los fármacos , Factores de TiempoRESUMEN
Neuronal damage in primary auditory cortex (A1) underlies complex manifestations of noise exposure, prevention of which is critical for health maintenance. Acid sphingomyelinase (ASM) catalyzes generation of ceramide (Cer) which if over-activated mediates neuronal disorders in various diseases. Tricyclic antidepressants (TCAs), by restraining ASM/Cer, benefits multiple neuronal anomalies, so we aimed to elucidate the effect of TCA on noise induced hearing loss and auditory cortex derangement, unraveling mechanism involved. The mice were exposed to noise with frequencies of 20-20 KHz and intensity of 95 dB. Doxepin hydrochloride (DOX), a kind of TCAs, was given intragastrically by 5 mg kg-1 days-1 . Morphology of neurons was examined using hematoxylin-eosin (HE) and Nissl staining. Apoptosis was assayed through transferase-mediated dUTP nick end labeling (TUNEL). The content of ASM, Cer or acid ceramidase (AC) was detected by western blot and immunohistochemistry analysis. We demonstrated intense, broad band noise caused upward shift of auditory brainstem response (ABR) threshold to sound over frequencies 4-32 KHz, with prominent morphologic changes and enhanced apoptosis in neurons of primary auditory cortex (A1) (P < 0.05). DOX partly restored noise-caused hearing loss alleviating morphologic changes or apoptosis remarkably (P < 0.05). Both ASM and Cer abundance were elevated significantly by noise which was reversed upon DOX treatment (P < 0.05), but neither noise nor DOX altered AC content. DOX had no influence on hearing, neuronal morphology or ASM/Cer in control mice. Our result suggests DOX palliates noise induced hearing loss and neuronal damage in auditory cortex by correcting over-activation of ASM/Cer without hampering intrinsic behavior of it. Anat Rec, 300:2220-2232, 2017. © 2017 Wiley Periodicals, Inc.
Asunto(s)
Corteza Auditiva/metabolismo , Ceramidas/metabolismo , Doxepina/farmacología , Pérdida Auditiva Provocada por Ruido/metabolismo , Ruido/efectos adversos , Esfingomielina Fosfodiesterasa/metabolismo , Estimulación Acústica/efectos adversos , Animales , Antidepresivos Tricíclicos/farmacología , Antidepresivos Tricíclicos/uso terapéutico , Corteza Auditiva/efectos de los fármacos , Corteza Auditiva/patología , Ceramidas/antagonistas & inhibidores , Doxepina/uso terapéutico , Pérdida Auditiva Provocada por Ruido/tratamiento farmacológico , Pérdida Auditiva Provocada por Ruido/patología , Masculino , Ratones , Neuronas/efectos de los fármacos , Neuronas/metabolismo , Neuronas/patología , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiología , Esfingomielina Fosfodiesterasa/antagonistas & inhibidoresRESUMEN
BACKGROUND/AIMS: High concentration of bile acids (BAs) induces hydrophobicity-dependent vasorelaxtant effects with hydrophobic BAs showing greater responses than hydrophilic BAs, of which the underlying mechanisms are still unclear. Caveolae are invaginations on membranes of endothelial cells (ECs) entraping endothelial nitric oxide synthase (eNOS) to prevent its activation, which plays a critical role in regulation of vascular function. The purpose of the present study was to investigate the role of caveolae in vasorelaxant effects of BAs. METHODS: Chenodeoxycholic acid (CDCA) and cholic acid (CA) were used to represent hydrophobic and hydrophilic BA, respectively. Vascular responses of abdominal aorta were measured by isometric force recording. Morphology of caveolae was examined by transmission electron microscopy. Protein expression of total eNOS (t-eNOS) or phosphorylated eNOS (p-eNOS) was determined by Western blot. Nitric oxide (NO) content was observed by fluorometric assay. RESULTS: We demonstrated that CDCA as well as Methyl-ß-cyclodextrin (MCD), a commonly used reagent for cholesterol depletion, reduced potassium chloride (KCl)- or phenylephrine (PE)-elicited vasoconstriction (P < 0.05), and enhanced acetylcholine (Ach)-elicited vasodilatation (P < 0.05) in endothelium-intact abdominal aorta but not in endothelium-denuded or CA-treated vessels. CDCA and MCD, but not CA significantly disrupted caveolae structure on ECs of abdominal aorta which was recovered by cholesterol incubation (P < 0.05). Protein expression of t-eNOS was significantly decreased (P < 0.05), and that of p-eNOS together with NO content was significantly increased in CDCA- and MCD- but not CA-treated vessels (P < 0.05) as compared with vehicle. The effect was reversed by either endothelium-denudation or cholesterol replenishment. Moreover, with cholesterol incubation, no significant differences were found in vascular responses among CDCA-, CA- or vehicle-treated vessels. CONCLUSION: These results indicate that CDCA diminishes caveolae on ECs of abdominal aorta promoting eNOS phosphorylation and NO production which contributes to its vasorelaxtant effect.
Asunto(s)
Aorta/efectos de los fármacos , Caveolas/efectos de los fármacos , Ácido Quenodesoxicólico/farmacología , Endotelio Vascular/efectos de los fármacos , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacología , Animales , Aorta/fisiología , Caveolas/metabolismo , Caveolas/ultraestructura , Ácido Cólico/farmacología , Endotelio Vascular/metabolismo , Endotelio Vascular/ultraestructura , Masculino , Óxido Nítrico/análisis , Óxido Nítrico/metabolismo , Óxido Nítrico Sintasa de Tipo III/análisis , Óxido Nítrico Sintasa de Tipo III/metabolismo , Ratas Sprague-Dawley , Vasoconstricción/efectos de los fármacosRESUMEN
Structural adaptation of arteries to weightlessness might lower the working ability or even threaten the physical health of astronauts, but the underlying mechanism is unclear. Acid sphingomyelinase (ASM) catalyzes ceramide (Cer) generation controlling arterial remodeling through multiple signaling pathways. In the present study, we aimed to investigate the contribution of ASM/Cer to the changes of common carotid artery intima-media thickness (CIMT) induced by simulated weightlessness. Hindlimb-unloaded tail-suspended (HU) rats were used to simulate the effect of weightlessness. Morphology of the carotid artery (CA) was examined by hematoxylin-eosin staining. Protein content of ASM or proliferating cell nuclear antigen (PCNA) was detected by Western blot. Cer level was measured by immunohistochemistry analysis. Apoptosis events were observed by transferase-mediated dUTP nick end labeling (TUNEL) staining. During 4 weeks of tail suspension, CIMT was increased gradually in HU but not in their synchronous control rats (P < 0.05). Correspondingly, the CA of HU rats had a lower apoptosis and higher proliferation of vascular smooth muscle cells (VSMCs). As compared to the control, both ASM protein expression and Cer content were reduced significantly in CA of HU rats (P < 0.05), incubation of which with permeable Cer reversed the changes in apoptosis and proliferation substantially. Furthermore, when the ASM protein content as well as Cer level in CA of control rats was diminished by using an ASM inhibitor, an increase of CIMT along with reduced apoptosis and enhanced proliferation of VSMCs was found. Our results suggest that by controlling the balance between apoptosis and proliferation, ASM/Cer plays an important role in the regulation of CIMT during simulated weightlessness.
Asunto(s)
Arterias Carótidas/metabolismo , Ceramidas/metabolismo , Suspensión Trasera/efectos adversos , Miocitos del Músculo Liso/metabolismo , Esfingomielina Fosfodiesterasa/metabolismo , Túnica Íntima/metabolismo , Animales , Apoptosis , Arterias Carótidas/citología , Proliferación Celular , Masculino , Miocitos del Músculo Liso/fisiología , Ratas , Ratas Sprague-Dawley , Esfingomielina Fosfodiesterasa/genética , Túnica Íntima/citologíaRESUMEN
Sphingolipids (SLs) are compounds containing a long-chain fatty alcohol amine called sphingosine which exists in cellular membranes, cytoplasm, nucleus, interstitial fluid, blood and lymphatic circulation. SLs act as essential constituents of membranes of eukaryotic cells, so the seesaw of SLs will lead to structural alteration of membranes instigating cellular functional change. SLs also act as crucial signaling molecules taking effect intracellularly or extracellularly which regulates activity of downstream molecules determining cellular adaptation to numerous stimulus. This review aims to highlight the contribution of SLs to physiological and pathophysiological remodeling of vasculature. We will first provide a short overview on metabolism, trafficking and compartmentalization of SLs. Then the regulation of SLs on reactive oxygen species (ROS) formation, vascular tone modulation, endothelial barrier integrity, apoptosis and autophagy are summarized. Finally, we will discuss how the SLs are modulated contributing to vascular development, angiogenesis and vascular remodeling in pathological situations as hypertension, atherosclerosis, and aging. The compellingly regulative actions of SLs bring about copious therapeutic targets for potential pharmacological intervention on the diseases involving vascular maladaptation.
Asunto(s)
Vasos Sanguíneos/fisiología , Esfingolípidos/fisiología , Adaptación Fisiológica , Envejecimiento/patología , Envejecimiento/fisiología , Animales , Apoptosis , Aterosclerosis/fisiopatología , Vasos Sanguíneos/citología , Movimiento Celular , Proliferación Celular , Humanos , Hipertensión/fisiopatología , Deficiencia de Magnesio/fisiopatología , Neovascularización Patológica , Neovascularización Fisiológica , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Weightlessness induces the functional remodelling of arteries, but the changes to angiotensin II (Ang II)-elicited vasoconstriction and the underlying mechanism have never been reported. Caveolae are invaginations of the cell membrane crucial for the contraction of vascular smooth muscle cells, so we investigated the adaptation of Ang II-elicited vasoconstriction to simulated weightlessness and the role of caveolae in it. The 4 week hindlimb unweighted (HU) rat was used to simulate the effects of weightlessness. Ang II-elicited vasoconstriction was measured by isometric force recording. The morphology of caveolae was examined by transmission electron microscope. The binding of the angiotensin II type 1 receptor (AT1 ) and caveolin-1 (cav-1) was examined by coimmunoprecipitation and Western blot. We found that the maximal developing force (E(max)) of Ang II-elicited vasoconstriction was decreased in abdominal aorta by 30.6%, unchanged in thoracic aorta and increased in carotid artery by 17.9% after HU, while EC50 of the response was increased in all three arteries (P < 0.05). AT1 desensitization upon activation was significantly reduced by HU in all three arteries, as was the number of caveolae (P < 0.05). Furthermore, Ang II promoted the binding of AT1 and cav-1 significantly in control but not HU arteries. Both the number of caveolae and the binding of AT1 and cav-1 in HU arteries were restored by cholesterol pretreatment which also reinstated the change in EC50 as well as the level of AT1 desensitization. These results indicate that modified caveolae in vascular smooth muscle cells could interfere with the binding of AT1 and cav-1 mediating the adaptation of Ang II-elicited vasoconstriction to HU.
Asunto(s)
Angiotensina II/farmacología , Aorta Abdominal/fisiología , Aorta Torácica/fisiología , Arterias Carótidas/fisiología , Caveolas/fisiología , Vasoconstricción/efectos de los fármacos , Animales , Aorta Abdominal/efectos de los fármacos , Aorta Torácica/efectos de los fármacos , Arterias Carótidas/efectos de los fármacos , Caveolina 1/metabolismo , Colesterol/farmacología , Miembro Posterior , Suspensión Trasera/fisiología , Masculino , Músculo Liso Vascular/fisiología , Miocitos del Músculo Liso/fisiología , Ratas Sprague-Dawley , Receptor de Angiotensina Tipo 1/metabolismo , Vasoconstricción/fisiología , IngravidezRESUMEN
Previous studies have demonstrated inconsistent roles of Rho kinase (ROCK) in the decreased vasoconstriction of rat hindquarter vessels induced by hindlimb unweighting (HU). The present study was designed to determine the unclear role of ROCK in the mediation of HU-induced decreased femoral arterial vasoconstriction. 28-day HU rat was adopted as the animal model. With or without Y-27632, a ROCK inhibitor, isometric force of femoral artery was measured. The expression of ROCK and its effects on downstream targets were also examined. Results showed that (1) HU caused a significant decrease of the phenylephrine (PE)-evoked and potassium chloride (KCl)-evoked femoral arterial vasoconstriction (P < 0.05), confirming the functional findings by previous studies. (2) Inhibition of ROCK with Y-27632 produced an equal reduction of the vasoconstriction in CON and HU. (3) HU significantly decreased ROCK II expression and the effects of ROCK on myosin light-chain phosphatase (MLCP) and MLC (P < 0.05), but increased p65 nuclear translocation (P < 0.05) and inducible nitric oxide synthase (iNOS) expression (P < 0.05). (4) HU significantly (P < 0.05) increased NO production in femoral arteries, with Y-27632 significantly (P < 0.01) amplifying this effect. These findings have revealed that 28-day HU reduced the expression and effects of ROCK on downstream targets both directly (MLCP and MLC) and possibly indirectly (NF-κB/iNOS/NO pathway) related to vasoconstriction in femoral arteries
Asunto(s)
Animales , Ratas , Quinasas Asociadas a rho/fisiología , Arteria Femoral/fisiología , Suspensión Trasera/fisiología , Vasoconstricción/fisiología , FN-kappa B/análisisRESUMEN
Previous studies have demonstrated inconsistent roles of Rho kinase (ROCK) in the decreased vasoconstriction of rat hindquarter vessels induced by hindlimb unweighting (HU). The present study was designed to determine the unclear role of ROCK in the mediation of HU-induced decreased femoral arterial vasoconstriction. 28-day HU rat was adopted as the animal model. With or without Y-27632, a ROCK inhibitor, isometric force of femoral artery was measured. The expression of ROCK and its effects on downstream targets were also examined. Results showed that (1) HU caused a significant decrease of the phenylephrine (PE)-evoked and potassium chloride (KCl)-evoked femoral arterial vasoconstriction (P < 0.05), confirming the functional findings by previous studies. (2) Inhibition of ROCK with Y-27632 produced an equal reduction of the vasoconstriction in CON and HU. (3) HU significantly decreased ROCK II expression and the effects of ROCK on myosin light-chain phosphatase (MLCP) and MLC (P < 0.05), but increased p65 nuclear translocation (P < 0.05) and inducible nitric oxide synthase (iNOS) expression (P < 0.05). (4) HU significantly (P < 0.05) increased NO production in femoral arteries, with Y-27632 significantly (P < 0.01) amplifying this effect. These findings have revealed that 28-day HU reduced the expression and effects of ROCK on downstream targets both directly (MLCP and MLC) and possibly indirectly (NF-κB/iNOS/NO pathway) related to vasoconstriction in femoral arteries.