酒精性脂肪肝小鼠肝脏LXRα-SREBP-1c信号表达检测及葛花解酒涤脂汤干预作用

Detection of LXRα-SREBP-1c Signaling Expression in Liver of Alcoholic Fatty Liver Mice and Intervention of Gehua Jiejiu Dizhi Decoction(葛花解酒涤脂汤)

目的检测酒精性脂肪肝(alcoholic fatty liver disease, AFLD)小鼠肝组织肝脏X受体α(liver X receptorα, LXRα)及其调控的胆固醇调节元件结合蛋白-1c(sterol regulatory element binding protein-1c, SREBP-1c)表达水平,探讨LXRα与AFLD发生的相关性及葛花解酒涤脂汤的干预作用。方法将37只雄性C57BL/6J小鼠随机分为正常组,模型组,葛花解酒涤脂汤高、低剂量干预组,白藜芦醇干预组。采用Lieber-DeCarli经典法加1次95%乙醇灌胃的方法制备AFLD小鼠模型并分别灌胃给予干预组相应剂量的低、高剂量葛花解酒涤脂汤及白藜芦醇HS15溶液,连续9 d。采用油红O染色检测肝组织脂肪变性情况,实时荧光定量PCR及蛋白免疫印迹法检测肝组织LXRα及其调控的SREBP-1c mRNA及蛋白表达水平。结果模型组小鼠肝脏LXRα蛋白表达水平显著降低(P=0.01),葛花解酒涤脂汤高剂量干预后能显著上调LXRα蛋白表达水平(P=0.02),与正常组水平相似(P=0.1)。各组SREBP-1c mRNA表达水平相似,但AFLD小鼠肝组织SREBP-1c蛋白表达水平显著低于正常组、葛花解酒涤脂汤高剂量干预及白藜芦醇干预组(P=0.01)。葛花解酒涤脂汤高剂量干预组能显著降低模型组小鼠肝组织硬脂酰辅酶A脱氢酶-1(stearoyl-CoA desaturates, SCD)mRNA表达水平(P=0.03)。中药干预虽能降低模型组小鼠肝组织(fatty acid synthase, FAS) mRNA表达水平,差异无统计学意义(P=0.06)。结论 LXRα介导的胆固醇代谢障碍可能是AFLD发生的重要因素之一,通过上调SREBP-1c表达可能不是慢性酒精摄入后脂肪肝形成的关键因素;葛花解酒涤脂汤可通过上调肝脏LXRα表达改善AFLD小鼠胆固醇代谢异常。

Objective To detect the expression level of liver X receptor alpha(LXRα) in liver tissue of mice with alcoholic fatty liver(AFLD) and explore the correlation between LXRα and AFLD and the mechanism of Gehua Jiejiu Dizhi Decoction(葛花解酒涤脂汤,GJDD) in interfering with AFLD in mice. Method Thirty-seven male C57 BL/6 J mice were randomly divided into normal group, model group, high-dose intervention group, low-dose intervention group and resveratrol intervention group. AFLD mice were established by Lieber DeCarli classical method and 95% alcohol once by gavage. Then the low and high doses of GJDD and resveratrol HS15 solution were given intragastrically respectively for 9 days. Hepatic steatosis was detected by oil red O staining. The expressions of LXRα and its key lipid transcription factor sterol regulatory element binding protein-1 c(SREBP-1 c) in liver tissue were analyzed by real-time fluorescence quantitative PCR(qRT-PCR) and Western blot. Result GJDD could significantly ameliorate liver steatosis and lipid deposition in AFLD mice. The protein expression level of LXRα in the model group was significantly lower(P<0.05). After high dose intervention of GJDD, the expression level of LXRα protein in the model group was significantly increased(P<0.05), which was similar to that in the normal group(P=0.1). The expression level of SREBP-1 c protein in liver tissue of AFLD mice was significantly lower than that in the normal group, GJDD high-dose intervention group and resveratrol intervention group(P<0.05). GJDD high dose intervention group can significantly reduce the expression level of stearoyl-CoA desaturates(SCD) mRNA in liver tissue of AFLD mice(P<0.05). Traditional Chinese medicine intervention can reduce the expression level of fatty acid synthase(FAS) mRNA in the model group, but there was no significant difference(P=0.06). Conclusion LXRα-mediated cholesterol metabolism disorder may be one of the important factors leading to AFLD. Up-regulation of SREBP-1 c expression may not be the key factor of fatty liver formation after chronic alcohol intake. GJDD can improve the abnormal cholesterol metabolism of AFLD mice by up-regulating liver LXR α expression.