柴胡皂苷a通过影响PPARα信号通路对非酒精性脂肪性肝病大鼠肝脂肪变的保护作用

Protective effect of saikosaponin A on hepatic steatosis in rats with non-alcoholic fatty liver disease by affecting PPARαsignaling pathway

目的研究柴胡皂苷a(SSa)对非酒精性脂肪性肝病(NAFLD)大鼠肝脂肪变的保护作用,并探讨其可能的作用机制。方法将46只大鼠随机分为对照组、NAFLD组、SSa干预组和SSa联合GW6471干预组,建立NAFLD模型,分别以生理盐水或SSa或SSa联合信号通路抑制剂GW6471灌胃或腹腔注射干预。采用Western blotting法检测肝组织5-单磷酸腺苷活化蛋白激酶(AMPK)、p-AMPK和抗过氧化物增殖物活化受体α(PPARα)蛋白表达,检测空腹血糖(FBG),空腹胰岛素(FINS),计算胰岛素抵抗指数(HOMA-IR)。结果NAFLD组大鼠FBG、FINS和HOMA-IR分别为(10.2±1.2)mmol/L、(24.2±2.3)mU/L、(11.0±2.1),显著高于对照组【分别为(4.7±0.5)mmol/L、(15.3±2.1)mU/L和(3.2±0.4),P<0.05】,而SSa干预组上述指标显著低于模型组【分别为(6.3±0.7)mmol/L、(18.6±2.5)mU/L和(5.2±0.6),P<0.05】,SSa联合GW6471干预组显著高于SSa干预组【分别为(8.1±1.0)mmol/L、(21.7±2.8)mU/L和(7.8±0.9),P<0.05】;模型组肝指数、肝组织TC、TG和FFA含量分别为(3.3±0.3)%、(0.8±0.1)mmol/g、(1.1±0.1)mmol/g和(543.6±62.7)mmol/g,显著高于对照组【分别为(2.2±0.2)%、(0.3±0.1)mmol/g、(0.5±0.1)mmol/g和(406.5±58.9)mmol/g,P<0.05】,SSa干预组上述指标均显著低于NAFLD组,SSa联合GW6471干预组上述指标均显著高于SSa干预组(P<0.05);SSa干预组和SSa联合GW6471干预组肝组织脂滴显著减少,其中SSa组脂滴少于SSa联合GW6471组;NAFLD组大鼠肝组织PPARα蛋白相对表达量和p-AMPK/AMPK比值均显著低于对照组(P<0.05),而SSa干预组肝组织PPARα蛋白和p-AMPK/AMPK比值均显著升高(P<0.05),SSa联合GW6471干预组肝组织两指标均显著降低(P<0.05)。结论SSa可改善NAFLD大鼠肝脂肪变程度,可能与激活了PPARα信号通路和抑制了胰岛素抵抗有关。

Objective This experiment aimed to explore protective effect of saikosaponin A(SSa)on hepatic steatosis in rats with non-alcoholic fatty liver disease(NAFLD)by affecting peroxide proliferator activated receptorα(PPARα)signaling pathway.Methods 46 rats were randomly divided into control(n=10),NAFLD model(n=12),SSa-intervened(n=12)and SSa plus GW6471-intervened group(n=12),and NAFLD model was established by high fat diet feeding.After the model completed,the normal saline,or SSa or SSa and GW6471 were given by gavage and intraperitoneal injection,respectively.The hepatic adenosine 5′-monophosphate-activated protein kinase(AMPK),p-AMPK and PPARαexpression was detected by Western blotting.The fasting blood glucose(FBG),fasting insulin(FINS)and insulin resistance index(HOMA-IR)were detected and culculated.Results The FBG,FINS and HOMA-IR in model group were(10.2±1.2)mmol/L,(24.2±2.3)mU/L and(11.0±2.1),significantly higher than[(4.7±0.5)mmol/L,(15.3±2.1)mU/L and(3.2±0.4),respectively,P<0.05]in the control,while they decreased greatly in SSa-intervened group as compared to those in the model(P<0.05),e.g.(6.3±0.7)mmol/L,(18.6±2.5)mU/L and(5.2±0.6),respectively,and they increased in SSa and GW6471 combination group as compared to in the SSa-intervened group[(8.1±1.0)mmol/L,(21.7±2.8)mU/L and(7.8±0.9),respectively,P<0.05];the hepatic index,hepatic TC,TG and free fatty acid levels in the model were(3.3±0.3)%,(0.8±0.1)mmol/g,(1.1±0.1)mmol/g and(543.6±62.7)mmol/g,significantly higher than[(2.2±0.2)%,(0.3±0.1)mmol/g,(0.5±0.1)mmol/g and(406.5±58.9)mmol/g,P<0.05]in the control,they decreased greatly in SSa-intervened group compared to in the model,and they increased greatly in SSa and GW6471 combination intervention group compared to in SSa-intervened group(P<0.05);the hepatic steatosis improved obviously in SSa-and SSa plus GW6471-intervened groups compared to that in the model;the hepatic PPARαexpression and the p-AMPK/AMPK expression ratio in the model decreased greatly compared to in the control(P<0.05),while they both elevated in SSa-intervened group(P<0.05),and they decreased obviously in SSa and GW6471-intervened group(P<0.05).Conclusion SSa could improve hepatic steatosis in rats,which might be related to the activation of PPARαsignaling pathway and inhibit insulin resistance.