草质素对非酒精性脂肪性肝炎大鼠肝脂肪变和肝内氧化应激的影响

目的 探讨草质素对高脂饮食诱导的脂肪性肝病大鼠肝组织脂堆积和氧化应激的影响。方法 用高脂饮食诱导SD大鼠12周建立非酒精性脂肪性肝炎(NASH)模型,同时给予药物处理组动物草质素20 mg·kg^-1.d^-1和40 mg·kg^-1.d^-1灌胃。检测血清谷草转氨酶(AST)、谷丙转氨酶(ALT)、低密度脂蛋白(LDL-C)、甘油三酯(TG)、总胆固醇(TC)、游离脂肪酸(FFA)含量,检测肝匀浆TG、TC、FFA、丙二醛(MDA)和超氧化物岐化酶(SOD)、过氧化物酶(CAT)、谷胱甘肽过氧化物酶(GSH-Px)和血红素氧化酶(HO-1)活性,采用Western blotting法检测肝组织Nrf2、细胞色素P450酶2E1(CYP2E1)和细胞色素P450酶4A(CYP4A)蛋白表达量。结果 模型组大鼠体质量、肝质量和肝指数分别为(499.2±14.1)g、(15.9±0.6)g和(3.2±0.1)%,显著高于对照组;小剂量和大剂量草质素处理组大鼠体质量、肝质量和肝指数均显著低于模型组(P<0.05); 模型组大鼠血清FFA水平为(521.5±52.3) mmol/L],显著高于对照组;大剂量药物处理组大鼠血清FFA水平为(361.5±62.3)mmol/L,显著低于模型组(P<0.05);模型组大鼠肝匀浆SOD、CAT、GSH-Px和HO-1水平分别为(294.2±35.4)U/mg、(19.5±6.4)U/mg、(362.4±104.2)U/mg和(4.1±0.4)ng/mg,均显著低于对照组[分别为(402.3±58.4)U/mg、(42.3±5.2)U/mg、(732.3±134.3)U/mg和(13.2±1.0)ng/mg,P<0.05];小剂量和大剂量组大鼠肝匀浆SOD、GSH-Px和HO-1水平均显著高于模型组(P<0.05);模型组大鼠肝组织Nrf2蛋白相对表达量显著低于对照组,而CYP2E1和CYP4A蛋白相对表达量显著高于对照组(P<0.01);与模型组比,小剂量和大剂量药物处理组肝组织Nrf2蛋白相对表达量显著升高(P<0.01),而CYP2E1和CYP4A蛋白相对表达量显著降低(P<0.05)。结论 草质素可以改善NASH大鼠肝组织脂堆积和氧化应激紊乱,其抗氧化的机制可能与调节Nrf2表达有关。

Effects of herbacetin onhepatic steatosis and intrahepatic oxidative stress in rats with non-alcoholic steatohepatitis

Objective The aim of this study was to investigate the effects of herbacetin on hepatic steatosis and intrahepatic oxidative stress in rats with non-alcoholic steatohepatitis (NASH). Methods The high-fat diet was applied to induce SD rats for 12 weeks to establish models of NASH, and at the same time, the herbacetin at dose of 20 mg·kg^-1.d^-1 and 40 mg·kg^-1.d^-1 were administered daily intragastricly. Serum free fatty acid (FFA) , malondialdehyde (MDA) in liver homogenate, and activities of superoxide dismutase (SOD), peroxidase (CAT), glutathione peroxidase (GSH-Px) and heme oxidase (HO-1) were detected. The hepatic protein expression of Nrf2, cytochrome P450 enzyme 2E1 (CYP2E1) and cytochrome P450 enzyme 4A (CYP4A) were assayed by Western blotting. Results The body weight, liver weight and liver indexin model group were (499.2±14.1) g, (15.9±0.6) g and (3.2±0.1)% , much higher than in the control; the body weight, liver weight and liver index in low-dose and high-dose of herbacetin-intervened group were much lower than those in the model (P<0.05); serum FFA level in the model was (521.5±52.3) mmol/L, significantly higher than in the control; the liver homogenate levels of SOD, CAT, GSH-Px and HO-1 in the model were (294.2±35.4) U/mg, (19.5±6.4) U/mg, (362.4±104.2) U/mg and (4.1±0.4) ng/mg, all significantly lower than in the control; the liver homogenate levels of SOD, GSH-Px and HO-1 in low-dose and high-dose of herbacetin-intervened group were much higher than those in the model (P<0.05); the hepatic Nrf2 expression in the model was significantly weaker than that in the control, while the hepatic CYP2E1 and CYP4A expression was much stronger than in the control (P<0.01); the hepatic Nrf2 expression in low-dose and high-dose of herbacetin-intervened group increased(P<0.01), while hepatic CYP2E1 and CYP4A expression deeply decreased as compared to those in the model (P<0.05). Conclusion The herbacetin could improve lipid accumulation and oxidative stress disorder in the liver tissues of rats with NASH, and the anti-oxidation mechanism might be related to the regulation of Nrf2 gene expression.