The Effects And Mechanisms Of SIRT1 Activator Resveratrol And Melatonin On Antituberculosis Drug-induced Liver Injury In Rats

Objective(1) To observe the changes of expression of Sirtuin 1(SIRT1)and endoplasmic reticulum stress associated proteins, glucose regulated protein78(GRP78) and CCAAT/enhancer-binding protein homologous protein(CHOP) in rat liver injury induced by antituberculosis drugs. And study the the effects oand the possible mechanisms f resveratrol on liver injury.(2)To investigate the effects and the possible mechanisms of melatonin on antituberculosis drugs induced rat liver injury.Methods(1) 32 Male SD rats were randomly divided into four groups, normal group, model group, resveratrol group and rifampicin group. Each group consisted of 8 animals. Liver injury in model and resveratrol group was induced by rifampicin 50 mg·kg-1·d-1 and isoniazid.50 mg·kg-1·d-1 throughed gastric intubation. Rifampicin group were given rifampicin 50 mg·kg-1·d-1 only. Rats in resveratrol group recevied intraperitoneal injections(i.p.) of resveratrol at a dose of 15 mg/kg prior to gastric intubation, while others received i.p. of vehicle as control. Rats were sacrificed after three weeks. Serum biochemical parameters of liver such as alanine aminotransferase(ALT), aspartate aminotransferase(AST), total bilirubin(TBIL), direct bilirubin(DBIL), alkaline phosphatase(ALP) and total bile acid(TBA) were determined by using an automated chemistry analyzer. Superoxide dismutase(SOD) activity and malondialdehyde(MDA) concentration in liver tissues were detected. Pathological changes of liver tissue were detected. The expression of SIRT1 as well as GRP78 and CHOP, markers ofendoplasmic reticulum(ER) stress, were analyzed by western blot.(2) 24 Male SD were randomly divided into three groups of eight, control group, model group and melatonin group. Liver injury was induced by rifampicin 50 mg·kg-1·d-1 and isoniazid.50 mg·kg-1·d-1 throughed gastric intubation. Melatonin group were recevied i.p. of melatonin at a dose of 5 mg/kg prior to to isoniazid and rifampicin administration. The rest animals were administered i.p. of vehicle as control. Three weeks later, all the rats were sacrificed. Liver injury were assessed biochemically and histologically. SOD activity and MDA concentration in liver tissues were determined. The expression of SIRT1, GRP78 and CHOP were analyzed by western blot.Results(1) Compared with normal group, serum TBIL, DBIL, ALP, TBA in model and rifampicin group were significantly elevated(P<0.05), with no increase in aminotransferases(P>0.05) in model and rifampicin group. hepatocyte degeneration with fatty degeneration and neutrophil infiltrationin were found in rat liver in model group. Hepatocyte fatty change was only observed in rifampicin group. MDA content was increased and SOD activity was reduced(P<0.05). The reduced expression of SIRT1 and increased GRP78 and CHOP expression was detected. Compared with model group, resveratrol significantly reduced levels of serum TBIL, DBIL, TBA and ALP(P<0.05), reduced MDA content and increased SOD activity in rat liver(P<0.05), ameliorated pathological changes of liver, increased the expression of SIRT1 and reduced GRP78 and CHOP expression in rat liver(P<0.05).(2) Compared with model group, melatonin significantly attenuated changes of serum biochemical parameters and liver histopathological changes in rats with liver injury induced by isoniazid and rifampicin,melatonin induced MDA content and increased SOD activity elevation in rat liver(P<0.05). The expression of SIRT1 was significantly increased by melatonin. GRP78 and CHOP expression was significantly inhibited in melatonin treated rats.Conclusions(1) The expression of SIRT1 is down-regulated in rat liver injury induced by rifampicin or rifampicin plus isoniazid was reduced,while the expression of GRP78 and CHOP was up-regulated, which suggested that SIRT1, endoplasmic reticulum stress colud play an important role in antituberculosis drug-induced rat liver injury.(2) Resveratro, a SIRT1 activator, attenuates isoniazid and rifampicin-induced liver injury in rats. The mechanisms may via SIRT1 mediated oxidative stress and ER stress pathway.(3) The protective effects of melatonin on the liver injury induced by rifampicin and isoniazid may be related to the activation of SIRT1 and subsequently inhibition of oxidative stress and ER sress.