RESUMEN
Many cancer patients receive their classical therapies together with vitamin supplements. However, the effectiveness of these strategies is on debate. Here we aimed to evaluate how vitamin E supplementation affects the anticancer effects of interferon (IFN-α) using an early-model of liver cancer development (initiation-promotion, IP). Male Wistar rats subjected to this model were divided as follows: untreated (IP), IP treated with recombinant IFN-α-2b (6.5 × 105 U/kg), IP treated with vitamin E (50 mg/kg), and IP treated with combination of vitamin E and IFN-α-2b. After treatments rats were fasted and euthanized and plasma and livers were collected. Combined administration of vitamin E and IFN-α-2b induced body weight drop, increased liver apoptosis, and low levels of hepatic lipids. Interestingly, vitamin E and IFN-α-2b combination also induced an increase in altered hepatic foci number, but not in size. It seems that vitamin E acts on its antioxidant capability in order to block the oxidative stress induced by IFN-α-2b, blocking in turn its beneficial effects on preneoplastic livers, leading to harmful final effects. In conclusion, this study shows that vitamin E supplementation in IFN-α-2b-treated rats exerts unwanted effects; and highlights that in spite of being natural, nutritional supplements may not always exert beneficial outcomes when used as complementary therapy for the treatment of cancer.
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Anticarcinógenos/farmacología , Interferón alfa-2/farmacología , Neoplasias Hepáticas/prevención & control , Vitamina E/farmacología , Vitaminas/farmacología , Animales , Carcinogénesis/efectos de los fármacos , Carcinogénesis/patología , Interacciones Farmacológicas , Hígado/efectos de los fármacos , Hígado/patología , Neoplasias Hepáticas/patología , Masculino , Ratas WistarRESUMEN
Accumulating evidence indicates the association between changes in circulating sex steroid hormone levels and the development of diabetic nephropathy. However, the renal synthesis of steroid hormones during diabetes is essentially unknown. Male Wistar rats were injected with streptozotocin (STZ) or vehicle. After one week, no changes in functional or structural parameters related to kidney damage were observed in STZ group; however, a higher renal expression of proinflammatory cytokines and HSP70 was found. Expression of Steroidogenic Acute Regulatory protein (StAR) and P450scc (CYP11A1) was decreased in STZ kidneys. Incubation of isolated mitochondria with 22R-hydroxycholesterol revealed a marked inhibition in CYP11A1 function at the medullary level in STZ group. The inhibition of these first steps of renal steroidogenesis in early STZ-induced diabetes led to a decreased local synthesis of pregnenolone and progesterone. These findings stimulate investigation of the probable role of nephrosteroids in kidney damage associated with diabetes.
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Diabetes Mellitus/metabolismo , Diabetes Mellitus/patología , Riñón/metabolismo , Riñón/patología , Esteroides/biosíntesis , Animales , Glucemia/metabolismo , Proteínas Portadoras/genética , Proteínas Portadoras/metabolismo , Enzima de Desdoblamiento de la Cadena Lateral del Colesterol/genética , Enzima de Desdoblamiento de la Cadena Lateral del Colesterol/metabolismo , Citocinas/genética , Citocinas/metabolismo , Diabetes Mellitus/sangre , Diabetes Mellitus/genética , Diabetes Mellitus Experimental/sangre , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/metabolismo , Diabetes Mellitus Experimental/patología , Regulación de la Expresión Génica , Proteínas HSP70 de Choque Térmico/genética , Proteínas HSP70 de Choque Térmico/metabolismo , Inflamación/patología , Mediadores de Inflamación/metabolismo , Riñón/fisiopatología , Metabolismo de los Lípidos , Masculino , Peroxidasa/metabolismo , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Pregnenolona/biosíntesis , Progesterona/sangre , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas Wistar , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo , Estreptozocina , Testosterona/sangreRESUMEN
Regeneration is the unmatched liver ability for recovering its functional mass after tissue lost. Leukotrienes (LT) are a family of eicosanoids with the capacity of signaling to promote proliferation. We analyzed the impact of blocking LT synthesis during liver regeneration after partial hepatectomy (PH). Male Wistar rats were subjected to two-third PH and treated with zileuton, a specific inhibitor of 5-lipoxygenase (5-LOX). Our first find was a significant increment of intrahepatic LTB4 during the first hour after PH together with an increase in 5-LOX expression. Zileuton reduced hepatic LTB4 levels at the moment of hepatectomy and also inhibited the increase in hepatic LTB4. This inhibition produced a delay in liver proliferation as seen by decreased PCNA and cyclin D1 nuclear expression 24 h post-PH. Results also showed that hepatic LTB4 diminution by zileuton was associated with a decrease in NF-ĸB activity. Additionally, decreased hepatic LTB4 levels by zileuton affected the recruitment of neutrophils and macrophages. Non-parenchymal cells (NPCs) from zileuton-treated PH-rats displayed higher apoptosis than NPCs from PH control rats. In conclusion, the present work provides evidences that 5-LOX activation and its product LTB4 are involved in the initial signaling events for liver regeneration after PH and the pharmacological inhibition of this enzyme can delay the initial time course of the phenomenon.
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Araquidonato 5-Lipooxigenasa/metabolismo , Leucotrieno B4/metabolismo , Regeneración Hepática/fisiología , Hígado/metabolismo , Animales , Apoptosis/efectos de los fármacos , Apoptosis/fisiología , Proliferación Celular/efectos de los fármacos , Proliferación Celular/fisiología , Ciclina D1/metabolismo , Eicosanoides/metabolismo , Hepatectomía/métodos , Concentración de Iones de Hidrógeno , Hidroxiurea/análogos & derivados , Hidroxiurea/farmacología , Leucotrienos/metabolismo , Hígado/efectos de los fármacos , Regeneración Hepática/efectos de los fármacos , Macrófagos/efectos de los fármacos , Macrófagos/metabolismo , Masculino , FN-kappa B/metabolismo , Neutrófilos/efectos de los fármacos , Neutrófilos/metabolismo , Ratas , Ratas Wistar , Transducción de Señal/efectos de los fármacos , Transducción de Señal/fisiologíaRESUMEN
Background: the shortage of donors of hepatocyte transplantation therapy led to the use of so-called marginal donors. Some donors may have a hepatic illnesses that is associated with hepatic preneoplasia with foci of altered hepatocytes (FAH). Aims: to determine whether recipients developed FAH upon transplantation with hepatocytes from a preneoplastic liver and whether FAH progresses to a preneoplastic hepatocyte-derived tumor (PHDT), up to 60 days after transplantation. Material and methods: male Wistar adult rats were used as donors and recipients. Donors underwent a 2-phase model of liver preneoplasia for hepatocyte isolation. Recipients underwent a partial two thirds hepatectomy and received 150,000 hepatocytes. Recipients were euthanized seven and 60 days after transplantation. The number of FAH per liver area, percentage of liver occupied by FAH, the hepatic enzymatic profile, the percentage of prothrombin time (PT), the proliferative index (PI) and liver morphology were analyzed. Results: recipients developed few and very isolated FAH. No statistical differences were found between hepatic enzyme activities and PT. There were no differences between the groups with regard to the number of FAH per liver area and percentage of liver occupied by FAH after 60 days. The PI decreased on day 60 compared to day seven. No morphological alterations were found. Conclusions: recipients developed few FAH that did not increase in number or size, nor did they progress to PHDT and had normal plasma biochemical features and liver morphology up to 60 days post-transplant. Additional studies are needed to determine whether FAH development constitutes a risk for recipients while waiting for whole organ transplant
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Animales , Ratas , Carcinoma Hepatocelular/patología , Hepatocitos/trasplante , Carcinogénesis/patología , Neoplasias Hepáticas/patología , Modelos Animales de Enfermedad , Lesiones Precancerosas/patología , Pruebas de Carcinogenicidad/métodos , Hepatocitos/patologíaRESUMEN
BACKGROUND: the shortage of donors of hepatocyte transplantation therapy led to the use of so-called marginal donors. Some donors may have a hepatic illnesses that is associated with hepatic preneoplasia with foci of altered hepatocytes (FAH). AIMS: to determine whether recipients developed FAH upon transplantation with hepatocytes from a preneoplastic liver and whether FAH progresses to a preneoplastic hepatocyte-derived tumor (PHDT), up to 60 days after transplantation. MATERIAL AND METHODS: male Wistar adult rats were used as donors and recipients. Donors underwent a 2-phase model of liver preneoplasia for hepatocyte isolation. Recipients underwent a partial two thirds hepatectomy and received 150,000 hepatocytes. Recipients were euthanized seven and 60 days after transplantation. The number of FAH per liver area, percentage of liver occupied by FAH, the hepatic enzymatic profile, the percentage of prothrombin time (PT), the proliferative index (PI) and liver morphology were analyzed. RESULTS: recipients developed few and very isolated FAH. No statistical differences were found between hepatic enzyme activities and PT. There were no differences between the groups with regard to the number of FAH per liver area and percentage of liver occupied by FAH after 60 days. The PI decreased on day 60 compared to day seven. No morphological alterations were found. CONCLUSIONS: recipients developed few FAH that did not increase in number or size, nor did they progress to PHDT and had normal plasma biochemical features and liver morphology up to 60 days post-transplant. Additional studies are needed to determine whether FAH development constitutes a risk for recipients while waiting for whole organ transplant.
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Hepatocitos/patología , Hepatocitos/trasplante , Neoplasias Hepáticas/patología , Hígado/cirugía , Lesiones Precancerosas/patología , Animales , Masculino , Ratas , Ratas WistarRESUMEN
In obstructive cholestasis, there is an integral adaptive response aimed to diminish the bile flow and minimize the injury of bile ducts caused by increased intraluminal pressure and harmful levels of bile salts and bilirrubin. Canalicular bicarbonate secretion, driven by the anion exchanger 2 (AE2), is an influential determinant of the canalicular bile salt-independent bile flow. In this work, we ascertained whether AE2 expression and/or activity is reduced in hepatocytes from rats with common bile duct ligation (BDL), as part of the adaptive response to cholestasis. After 4 days of BDL, we found that neither AE2 mRNA expression (measured by quantitative real-time PCR) nor total levels of AE2 protein (assessed by western blot) were modified in freshly isolated hepatocytes. However, BDL led to a decrease in the expression of AE2 protein in plasma membrane fraction as compared with SHAM control. Additionally, AE2 activity (JOH-, mmol/L/min), measured in primary cultured hepatocytes from BDL and SHAM rats, was decreased in the BDL group versus the control group (1.9 ± 0.3 vs. 3.1 ± 0.2, p<0.005). cAMP-stimulated AE2 activity, however, was not different between SHAM and BDL groups (3.7 ± 0.3 vs. 3.5 ± 0.3), suggesting that cAMP stimulated insertion into the canalicular membrane of AE2-containing intracellular vesicles, that had remained abnormally internalized after BDL. In conclusion, our results point to the existence of a novel adaptive mechanism in cholestasis aimed to reduce biliary pressure, in which AE2 internalization in hepatocytes might result in decreased canalicular HCO3- output and decreased bile flow.
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Bicarbonatos/metabolismo , Antiportadores de Cloruro-Bicarbonato/biosíntesis , Cloruros/metabolismo , Colestasis/metabolismo , Regulación hacia Abajo , Hepatocitos/metabolismo , Animales , Colestasis/patología , Modelos Animales de Enfermedad , Hepatocitos/patología , Transporte Iónico , Masculino , Ratas , Ratas WistarRESUMEN
We previously demonstrated in in vitro and ex vivo models that physiological concentrations of unconjugated bilirubin (BR) prevent oxidative stress (OS)-induced hepatocanalicular dysfunction and cholestasis. Here, we aimed to ascertain, in the whole rat, whether a similar cholestatic OS injury can be counteracted by heme oxygenase-1 (HO-1) induction that consequently elevates endogenous BR levels. This was achieved through the administration of hemin, an inducer of HO-1, the rate-limiting step in BR generation. We found that BR peaked between 6 and 8 h after hemin administration. During this time period, HO-1 induction fully prevented the pro-oxidant tert-butylhydroperoxide (tBuOOH)-induced drop in bile flow, and in the biliary excretion of bile salts and glutathione, the two main driving forces of bile flow; this was associated with preservation of the membrane localization of their respective canalicular transporters, bile salt export pump (Bsep) and multidrug resistance-associated protein 2 (Mrp2), which are otherwise endocytosed by OS. HO-1 induction counteracted the oxidation of intracellular proteins and membrane lipids induced by tBuOOH, and fully prevented the increase in the oxidized-to-total glutathione (GSHt) ratio, a sensitive parameter of hepatocellular OS. Compensatory elevations of the activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) were also prevented. We conclude that in vivo HO-1 induction protects the liver from acute oxidative injury, thus preventing consequent cholestasis. This reveals an important role for the induction of HO-1 and the consequently elevated levels of BR in preserving biliary secretory function under OS conditions, thus representing a novel therapeutic tool to limit the cholestatic injury that bears an oxidative background.
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Antioxidantes/farmacología , Colestasis/prevención & control , Hemo Oxigenasa (Desciclizante)/biosíntesis , Hemina/farmacología , Hígado/efectos de los fármacos , Estrés Oxidativo , Animales , Bilis/metabolismo , Bilirrubina/metabolismo , Catalasa/metabolismo , Colestasis/inducido químicamente , Colestasis/enzimología , Colestasis/patología , Modelos Animales de Enfermedad , Inducción Enzimática , Glutatión/metabolismo , Hígado/enzimología , Hígado/patología , Masculino , Ratas Wistar , Superóxido Dismutasa/metabolismo , terc-ButilhidroperóxidoRESUMEN
OBJECTIVE: Vitamin K2, which is present in dairy products and has been recommended as a micronutrient supplement in humans, contains anticancer properties. Interferon (IFN)-α-2b administered during development of hepatic preneoplasia decreased both number and volume percentage of altered hepatic foci (AHF) by increasing apoptosis in the foci. The aim of this study was to evaluate the effects of IFN-α-2b treatment supplemented with vitamin K2 in the early stages of liver cancer development in rats. METHODS: Adult male Wistar rats were subjected to a two-phase model of hepatocarcinogenesis (initiated-promoted [IP] group). Animals were divided into four groups: untreated (IP), IP treated with IFN-α-2b (6.5â¯×â¯105 U/kg), IP treated with vitamin K2 (10 mg/kg), and IP treated with both compounds. RESULTS: The study results demonstrated that vitamin K2 blocked IFN-α-2b-induced reduction in size and volume of the altered hepatic foci and inhibited IFN-α-2b-induced apoptosis. Its inhibition of IFN-α-2b-induced apoptosis was mediated by increased levels of total hepatic Bcl-2 in rat preneoplastic livers. CONCLUSION: These findings demonstrate that supportive vitamin supplements or therapies are not always safe because they could put the life of patients treated with IFN-α-2b at risk.
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Antineoplásicos/administración & dosificación , Carcinogénesis/efectos de los fármacos , Suplementos Dietéticos , Interferón alfa-2/administración & dosificación , Vitamina K 2/administración & dosificación , Vitaminas/administración & dosificación , Animales , Apoptosis/efectos de los fármacos , Hígado/efectos de los fármacos , Neoplasias Hepáticas/tratamiento farmacológico , Masculino , Lesiones Precancerosas/tratamiento farmacológico , Ratas , Ratas WistarRESUMEN
Obesity is accompanied by a low-grade inflammation state, characterized by increased proinflammatory cytokines levels such as tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1ß). In this regard, there exists a lack of studies in hepatic tissue about the role of TNFα receptor 1 (TNFR1) in the context of obesity and insulin resistance during the progression of nonalcoholic fatty liver disease (NAFLD). The aim of this work was to evaluate the effects of high-caloric feeding (HFD) (40% fat, for 16 weeks) on liver inflammation-induced apoptosis, insulin resistance, hepatic lipid accumulation and its progression toward nonalcoholic steatohepatitis (NASH) in TNFR1 knock-out and wild-type mice. Mechanisms involved in HFD-derived IL-1ß release and impairment of insulin signaling are still unknown, so we determined whether IL-1ß affects liver insulin sensitivity and apoptosis through TNFα receptor 1 (TNFR1)-dependent pathways. We showed that knocking out TNFR1 induces an enhanced IL-1ß plasmatic release upon HFD feed. This was correlated with higher hepatic and epididymal white adipose tissue mRNA levels. In vivo and in vitro assays confirmed an impairment in hepatic insulin signaling, in part due to IL-1ß-induced decrease of AKT activation and diminution of IRS1 levels, followed by an increase in inflammation, macrophage (resident and recruited) accumulation, hepatocyte apoptotic process and finally hepatic damage. In addition, TNFR1 KO mice displayed higher levels of pro-fibrogenic markers. TNFR1 signaling disruption upon an HFD leads to an accelerated progression from simple steatosis to a more severe phenotype with many NASH features, pointing out a key role of TNFR1 in NAFLD progression.
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Dieta Alta en Grasa/efectos adversos , Enfermedad del Hígado Graso no Alcohólico/etiología , Receptores Tipo I de Factores de Necrosis Tumoral/metabolismo , Animales , Apoptosis/genética , Insulina/metabolismo , Resistencia a la Insulina , Interleucina-1beta/metabolismo , Hígado/metabolismo , Hígado/patología , Macrófagos/metabolismo , Macrófagos/patología , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Enfermedad del Hígado Graso no Alcohólico/patología , Receptores Tipo I de Factores de Necrosis Tumoral/genética , Transducción de SeñalRESUMEN
PURPOSE: Glycerol usage is increasing in food industry for human and animal nutrition. This study analyzed the impact of glycerol metabolism when orally supplemented during the early stage of rat liver carcinogenesis. METHODS: Wistar rats were subjected to a 2-phase model of hepatocarcinogenesis (initiated-promoted, IP group). IP animals also received glycerol by gavage (200 mg/kg body weight, IPGly group). RESULTS: Glycerol treatment reduced the volume of preneoplastic lesions by decreasing the proliferative status of liver foci, increasing the expression of p53 and p21 proteins and reducing the expression of cyclin D1 and cyclin-dependent kinase 1. Besides, apoptosis was enhanced in IPGly animals, given by an increment of Bax/Bcl-2 ratio, Bad and PUMA mitochondrial expression, a concomitant increase in cytochrome c release and caspase-3 activation. Furthermore, hepatic levels of glycerol phosphate and markers of oxidative stress were increased in IPGly rats. Oxidative stress intermediates act as intracellular messengers, inducing p53 activation and changes in JNK and Erk signaling pathways, with JNK activation and Erk inhibition. CONCLUSION: The present work provides novel data concerning the preventive actions of glycerol during the development of liver cancer and represents an economically feasible intervention to treat high-risk individuals.
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Anticarcinógenos/uso terapéutico , Apoptosis , Suplementos Dietéticos , Glicerol/uso terapéutico , Neoplasias Hepáticas Experimentales/prevención & control , Estrés Oxidativo , Lesiones Precancerosas/prevención & control , Animales , Anticarcinógenos/sangre , Anticarcinógenos/metabolismo , Biomarcadores/sangre , Carcinogénesis , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Proliferación Celular , Regulación Neoplásica de la Expresión Génica , Glicerol/sangre , Glicerol/metabolismo , Peroxidación de Lípido , Hígado/enzimología , Hígado/metabolismo , Hígado/patología , Neoplasias Hepáticas Experimentales/sangre , Neoplasias Hepáticas Experimentales/metabolismo , Neoplasias Hepáticas Experimentales/patología , Sistema de Señalización de MAP Quinasas , Masculino , Mitocondrias Hepáticas/enzimología , Mitocondrias Hepáticas/metabolismo , Mitocondrias Hepáticas/patología , Proteínas de Neoplasias/genética , Proteínas de Neoplasias/metabolismo , Fosforilación , Lesiones Precancerosas/sangre , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/patología , Ratas Wistar , Carga TumoralRESUMEN
Acetaminophen (APAP) is a widely prescribed analgesic and antipyretic drug. In the present work, we studied the effects of glutamine (Gln) in an in vivo model of APAP-induced nephrotoxicity in male Wistar rats. Renal function, histological characteristics, and Na+,K+-ATPase cortical abundance and distribution were analyzed. The appearance of HSP70 and actin in urine was also evaluated. Myeloperoxidase (MPO) activity in cortical tissue was measured as an index of the inflammatory response. Gln administration 30 min before APAP protected from the renal functional and histological damage promoted by APAP. Rats that received the dual treatment Gln and APAP (Gln/APAP) showed the same level of Na+,K+-ATPase cortical induction as APAP-treated animals, but the enzyme maintained its normal basolateral localization. HSP70 abundance was increased up to the same level in the Gln, APAP, and Gln/APAP groups. Urinary HSP70 and actin were detected only in the APAP-treated animals, reinforcing the protection of renal tubular integrity afforded by the Gln pretreatment. Gln pretreatment also protected from the increment in MPO activity promoted by APAP. Our results support the idea that Gln pretreatment could be a therapeutic option to prevent APAP-induced renal injury.
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Acetaminofén/efectos adversos , Glutamina/uso terapéutico , Enfermedades Renales/inducido químicamente , Enfermedades Renales/tratamiento farmacológico , Sustancias Protectoras/uso terapéutico , Actinas/metabolismo , Animales , Modelos Animales de Enfermedad , Glutamina/farmacología , Proteínas HSP70 de Choque Térmico/metabolismo , Proteínas HSP70 de Choque Térmico/orina , Riñón/efectos de los fármacos , Riñón/patología , Riñón/fisiopatología , Enfermedades Renales/patología , Enfermedades Renales/fisiopatología , Masculino , Peroxidasa/metabolismo , Sustancias Protectoras/farmacología , Transporte de Proteínas/efectos de los fármacos , Ratas Wistar , ATPasa Intercambiadora de Sodio-Potasio/metabolismoRESUMEN
It is accepted that cancer development is associated with metabolic changes. Previously, we established a model of hepatic preneoplasia in which adult rats were subjected to a 2-phase model of hepatocarcinogenesis (initiated-promoted, IP) for 6weeks until they develop altered hepatic foci (AHF). Here, we found that a whole metabolic shift occurs in order to favor cancer development. IP animals presented with increased plasma lipids due to increased VLDL secretion as well as increased liver lipid accretion due to stimulated transacetylase activity rather than lipogenesis, compared to control rats. We found that carboxylesterase 3/triacylglycerol hydrolase (Ces3/Tgh) presented with a perilobular distribution surrounding lipid droplets in normal livers. However, it is downregulated both at the protein and mRNA level in liver homogenates and is almost undetectable inside the AHF with no changes in the surrounding tissue. Ces3/Tgh expression is regulated by ω-3 fatty acids, thus, supplementation of diet with fish oil, allowed the restoration of Ces3/Tgh expression inside the foci and, more interestingly, led to the decrease in number and volume of the AHF. These studies show a preventive role of Ces3/Tgh in liver cancer development.
RESUMEN
Background: Liver preneoplasia development in rats can be mimicked by an initiation-promotion model that induces the ppearance of altered hepatocyte foci (FAH). Aims: We compare two initiation-promotion models to evaluate the presence of FAH or additional hepatic pathologies in which other organs were affected up to five month post treatment. Material and methods: FAH were induced in male adult Wistar rats with two doses of dietylnitrosamine (DEN, 150 mg/kg bw) followed by 4 doses per week (3 weeks) of 2-acetylaminofluorene (2-AAF, 20 mg/kg bw) or with one dose of DEN (200 mg/kg bw) followed by 2 doses per week (3 weeks) of 2-AAF. DEN 150, DEN 200 and control rats (received the vehicle of the drugs) groups were compared. Rats were euthanized immediately after the last dose of 2-AAF, at 3, 4 and 5 months (n = 3 for euthanasia times per group). Samples of livers, lungs, idneys, pancreatic tissue and small bowel were processed for histological and immunohistochemical analysis. Results: FAH persisted for 5 months in all livers of the DEN groups. Three months after withdrawal of 2-AAF, one rat from DEN 150 group developed fibrosis and 5 months after 2-AAF removal another rat from the same group presented a microscopic hyperplastic nodule. Only the lungs had damages compatible with lesions induced by gavage-related reflux in DEN groups. Conclusion: We concluded that up to five month post treatments, FAH persisted in all the livers from DEN groups; livers from DEN 200 group showed no other hepatic lesions besides FAH, and only the lungs suffered pathological alterations in both treated groups (AU)
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Asunto(s)
Animales , Masculino , Ratas , Neoplasias Hepáticas Experimentales/inducido químicamente , Neoplasias Hepáticas Experimentales/complicaciones , Neoplasias Hepáticas Experimentales/diagnóstico , Dietilnitrosamina/administración & dosificación , Dietilnitrosamina/análisis , 2-Acetilaminofluoreno/administración & dosificación , 2-Acetilaminofluoreno/análisis , Modelos Animales , Hígado/anatomía & histología , Hígado , Hígado/patología , Hepatocitos , Hepatocitos/patología , Proyectos de Investigación/tendencias , Inmunohistoquímica/métodos , InmunohistoquímicaRESUMEN
BACKGROUND: Liver preneoplasia development in rats can be mimicked by an initiation-promotion model that induces the appearance of altered hepatocyte foc (FAH). AIMS: We compare two initiation-promotion models to evaluate the presence of FAH or additional hepatic pathologies in which other organs were affected up to five month post treatment. MATERIAL AND METHODS: FAH were induced in male adult Wistar rats with two doses of dietylnitrosamine (DEN, 150 mg/kg bw) followed by 4 doses per week (3 weeks) of 2-acetylaminofluorene (2-AAF, 20 mg/kg bw) or with one dose of DEN (200 mg/kg bw) followed by 2 doses per week (3 weeks) of 2-AAF. DEN 150, DEN 200 and control mice (received the vehicle of the drugs) groups were compared. Rats were euthanized immediately after the last dose of 2-AAF, at 3, 4 and 5 months (n = 3 euthanasia times per group). Samples of livers, lungs, kidneys, pancreatic tissue and small bowel were processed for histological and immunohistochemical analysis. RESULTS: FAH persisted for 5 months in all livers of the DEN groups. Three months after withdrawal of 2-AAF, one rat from the DEN 150 group developed fibrosis and 5 months after 2-AAF removal another rat from the same group presented a microscopic hyperplastic nodule. Only the lungs had damage compatible with lesions induced by gavage-related reflux in DEN groups. CONCLUSION: We concluded that up to five month post treatments, FAH persisted in all the livers from the DEN groups; livers from the DEN 200 group showed no other hepatic lesions besides FAH, and only the lungs suffered pathological alterations in both treated groups.
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Neoplasias Hepáticas Experimentales/patología , Neoplasias Hepáticas Experimentales/terapia , Lesiones Precancerosas/patología , Lesiones Precancerosas/terapia , 2-Acetilaminofluoreno , Animales , Carcinógenos , Dietilnitrosamina , Hepatocitos/patología , Hígado/patología , Neoplasias Hepáticas Experimentales/inducido químicamente , Pulmón/patología , Masculino , Lesiones Precancerosas/inducido químicamente , Ratas , Ratas WistarRESUMEN
BACKGROUND: One established model to induce hepatic preneoplasia (HP) (DEN 150) uses diethylnitrosamine (DEN) as initiator agent and 2-acetylaminofluorene (2-AAF) as a promoter drug. In addition, both chemicals cause liver cholestasis and fibrosis. AIM: We compared DEN 150 model with another adapted by us, DEN 200 to simplify the first one and to evaluate the effectiveness of both treatments to induce HP in rats. MATERIAL AND METHODS: Male Wistar rats were divided in 3 groups: controls; DEN 150 (rats received 2 doses of DEN, 150 mg/kg body weight, 2 weeks apart, and then 2-AAF, 20 mg/kg body weight, 4 doses per week during 3 weeks); and DEN 200 (rats received a single dose of DEN 200 mg/kg body weight, and 2 weeks apart 2-AAF, 20 mg/kg body weight, 2 doses per week during 3 weeks). Four hepatic enzymes, prothrombin time percentage, the number of bile ductules, total collagen amount, the number of altered hepatic foci (AHF) per liver and the percentage of liver occupied by foci were analyzed. Results. There were no differences in the number of AHF per liver between treated groups. Rats from DEN 200 group showed a significant diminution in the volume of liver occupied by foci. DEN 200 group had no fibrosis and better hemostatic conditions than DEN 150 group. Both groups developed cholestasis. CONCLUSION: In conclusion, both protocols are good alternatives to induce HP in rats and the new protocol proposed is an effective and a simple methodology to provide subclinic states of liver cancer.
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2-Acetilaminofluoreno , Dietilnitrosamina , Neoplasias Hepáticas/inducido químicamente , Hígado/patología , Lesiones Precancerosas/inducido químicamente , Animales , Conductos Biliares/patología , Biomarcadores de Tumor/metabolismo , Proliferación Celular , Modelos Animales de Enfermedad , Hemostasis , Hígado/enzimología , Cirrosis Hepática/inducido químicamente , Cirrosis Hepática/patología , Neoplasias Hepáticas/metabolismo , Neoplasias Hepáticas/patología , Masculino , Lesiones Precancerosas/metabolismo , Lesiones Precancerosas/patología , Ratas Wistar , Factores de TiempoRESUMEN
SCOPE: Quercetin is the most abundant flavonoid in human diet. It has special interest as it holds anticancerous properties. This study aims to clarify the mechanisms involved in quercetin effects during the occurrence of preneoplastic lesions in rat liver. METHODS AND RESULTS: Adult male Wistar rats were subjected to a two-phase model of hepatocarcinogenesis (initiated-promoted group). Initiated-promoted animals also received quercetin 10 and 20 mg/kg body weight (IPQ10 and IPQ20 groups, respectively). Antioxidant defenses were modified by quercetin administration at both doses. However, only IPQ20 group showed a reduction in number and volume of preneoplastic lesions. This group showed increased apoptosis and a reduction in the proliferative index. In addition, IPQ20 group displayed a reduction of cell percentages in G1 and S phases, accumulation in G2, and decrease in M phase, with reduced expression of cyclin D1, cyclin A, cyclin B, and cyclin-dependent kinase 1. Interestingly, peroxisome proliferator activated receptor-α levels were reduced in IPQ20 group. CONCLUSION: The outcomes of this study represent a significant contribution to the current understanding on the preventive mechanisms of quercetin during the early stages of liver cancer development, demonstrating that in addition to its known proapoptotic characteristics, the flavonoid modulates the expression of critical cell cycle regulators and peroxisome proliferator activated receptor-α activity.
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Apoptosis/efectos de los fármacos , Carcinogénesis/efectos de los fármacos , Puntos de Control del Ciclo Celular/efectos de los fármacos , Proliferación Celular/efectos de los fármacos , Neoplasias Hepáticas/prevención & control , Quercetina/farmacología , Animales , Proteína Quinasa CDC2/metabolismo , División Celular/efectos de los fármacos , Ciclina D1/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , PPAR alfa/metabolismo , Ratas , Ratas WistarRESUMEN
BACKGROUND: FoxO3a, a member of the FOXO family of transcription factors, is expressed in adult liver and modulates the expression of genes involved in apoptosis. FoxO3a is post-translationally regulated, negatively by PI3K/Akt and MAPK/Erk and positively by oxidative stress/JNK pathways. In previous works, we have demonstrated that interferon-α2b (IFN-α2b) induces apoptosis of hepatic preneoplastic foci through the production of reactive oxygen species (ROS). AIMS: To investigate the post-translational signal events triggered by the oxidative stress induced by IFN-α2b and the modulation of FoxO3a transcriptional activity during these events in rat preneoplastic liver. METHODS: Adult male Wistar rats were subjected to a two-phase model of hepatocarcinogenesis. A group of animals received IFN-α2b and another group received IFN-α2b and ascorbic acid (ASC), by intraperitoneal injection. Lipid peroxidation, immunohistochemistry, immunoblotting, co-immunoprecipitation and sqRT-PCR assays were performed to explore the role of ROS, JNK, Akt, Erk, FoxO3a, ß-catenin and PUMA in the IFN-α2b-mediated apoptotic mechanism. RESULTS: In vivo IFN-α2b treatment induced endogenous production of ROS which activated JNK. IFN-α2b blocked the activation of Akt and Erk, avoiding FoxO3a activity repression. Activated JNK was responsible for the nuclear translocation and transcriptional activity of FoxO3a which positively modulated the expression of PUMA, a proapoptotic player. In addition, nuclear FoxO3a competed for the nuclear ß-catenin associated to TCF, inhibiting the canonical Wnt signalling pathway. CONCLUSIONS: The data presented here propose a model in which in vivo IFN-α2b treatment induces nuclear translocation and transcriptional activity of FoxO3a, triggering the mitochondrial apoptotic pathway in hepatic preneoplastic foci.
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Apoptosis/genética , Carcinogénesis/efectos de los fármacos , Factores de Transcripción Forkhead/metabolismo , Regulación de la Expresión Génica/fisiología , Hígado/metabolismo , Estrés Oxidativo/fisiología , Transducción de Señal/fisiología , Animales , Proteína Forkhead Box O3 , Regulación de la Expresión Génica/genética , Immunoblotting , Inmunohistoquímica , Inmunoprecipitación , Interferón alfa-2 , Interferón-alfa/farmacología , Peroxidación de Lípido , Masculino , Modelos Biológicos , Procesamiento Proteico-Postraduccional/genética , Ratas , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , Proteínas Recombinantes/farmacología , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal/genéticaRESUMEN
The effects of the in vivo administration of baclofen on renal tubular transport and aquaporin-2 (AQP2) expression were evaluated. In conscious animals kept in metabolic cages, baclofen (0.01-1mg/kg, s.c.) induced a dose-dependent increment in the urine flow rate (UFR) and in sodium and potassium excretion, associated with an increased osmolal clearance (Closm), a diminished urine to plasma osmolality ratio (Uosm/Posm) and a decrease in AQP2 expression. The above mentioned baclofen effects on functional parameters were corroborated by using conventional renal clearance techniques. Additionally, this model allowed the detection of a diminution in glucose reabsorption. Some experiments were performed with water-deprived or desmopressin-treated rats kept in metabolic cages. Either water deprivation or desmopressin treatment decreased the UFR and increased the Uosm/Posm. Baclofen did not change the Uosm/Posm or AQP2 expression in desmopressin-treated rats; but it increased the UFR and diminished the Uosm/Posm and AQP2 expression in water-deprived animals. These results indicate that in vivo administration of baclofen promotes alterations in proximal tubular transport, since glucose reabsorption was decreased. The distal tubular function was also affected. The increased Closm indicates an alteration in solute reabsorption at the ascending limb of the Henle's loop. The decreased Uosm/Posm and AQP2 expression in controls and in water-deprived, but not in desmopressin-treated rats, lead us to speculate that some effect of baclofen on endogenous vasopressin availability could be responsible for the impaired urine concentrating ability, more than any disturbance in the responsiveness of the renal cells to the hormone.
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Baclofeno/administración & dosificación , Baclofeno/farmacología , Túbulos Renales/efectos de los fármacos , Túbulos Renales/fisiología , Animales , Acuaporina 2/metabolismo , Estado de Conciencia , Desamino Arginina Vasopresina/farmacología , Relación Dosis-Respuesta a Droga , Regulación de la Expresión Génica/efectos de los fármacos , Túbulos Renales/metabolismo , Masculino , Ratas , Ratas Wistar , Agua/metabolismoRESUMEN
Diabetes mellitus is a risk factor for prognosis after liver resection. In previous work, we found a pro-apoptotic state in the diabetic rat liver. In this work, this was also observed 1 hour post-partial hepatectomy (PH) and resulted in a deficient regenerative response 24 hours post-PH. Treatment with insulin and/or Desferoxamine (DES) (iron chelator) or Tempol (TEM) (free radicals scavenger) was effective in preventing the liver reactive oxygen species (ROS) production induced by diabetic state. High levels of ROS play a role in hepatic lipid peroxidation in diabetes before and after PH, and lead to increased pro-apoptotic events, which contribute to a reduced regenerative response. This becomes of relevance for the potential use of antioxidants/free radical scavengers plus insulin for improvement of post-surgical recovery of diabetic patients subjected to a PH.
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Diabetes Mellitus Experimental/metabolismo , Regeneración Hepática/fisiología , Especies Reactivas de Oxígeno/metabolismo , Animales , Óxidos N-Cíclicos/farmacología , Deferoxamina/farmacología , Diabetes Mellitus Experimental/fisiopatología , Modelos Animales de Enfermedad , Hepatectomía , Insulina/farmacología , Peroxidación de Lípido/efectos de los fármacos , Hígado/efectos de los fármacos , Hígado/metabolismo , Hígado/fisiopatología , Pronóstico , Ratas , Ratas Wistar , Marcadores de Spin , EstreptozocinaRESUMEN
We analyzed the contribution of TNF-α intracellular pathway in the development of apoptosis in the liver of streptozotocin-induced diabetic rats. In liver tissue, diabetes promoted a significant increase of TNF-α/TNF-R1, and led to the activation of caspase-8, of nuclear factor kappa B (NFκB), and JNK signaling pathways. The activation of NFκB led to an induction of iNOS and consequent increase in NO production. As a consequence of such changes a significant increase of caspase-3 activity and of apoptotic index were observed in the liver of diabetic animals. Importantly, the treatment in vivo of diabetic rats with etanercept (TNF-α blocking antibody) or aminoguanidine (selective iNOS inhibitor) significantly attenuated the induction of apoptosis by reduction of caspase-3 activity. Overall, we demonstrated that in the diabetes enhances TNF-α in the liver, which may be a fundamental key leading to apoptotic cell death, through activation of caspase-8, NFκB and JNK pathways.