黄连温胆汤对胰岛素抵抗大鼠肝脏脂质蓄积的影响

目的观察黄连温胆汤对胰岛素抵抗(IR)大鼠肝脏脂质蓄积的影响,从自噬角度探讨其作用机制。方法50只雄性SD大鼠随机分为空白组10只和造模组40只,造模组采用高脂高糖饮食诱导IR大鼠模型,将成模大鼠随机分为模型组、黄连温胆汤组和二甲双胍组,分别予蒸馏水、黄连温胆汤药液和二甲双胍溶液灌胃,连续8周。透射电镜观察大鼠肝组织自噬小体形成情况;油红O染色观察肝脏脂质蓄积;ELISA检测大鼠空腹血糖(FPG)、空腹胰岛素(FINS),计算胰岛素抵抗指数(HOMA-IR);GPO-PAP法检测大鼠肝组织三酰甘油(TG)、总胆固醇(TC)含量;Western blot检测肝组织LC3、p62、哺乳动物雷帕霉素靶蛋白(mTOR)和p-mTOR蛋白表达;RT-PCR检测肝组织mTOR mRNA表达。结果与空白组比较,模型组大鼠肝组织红色脂滴明显增多,并有少量自噬小体形成,FPG、FINS和HOMA-IR明显升高(P<0.01),肝组织TC、TG含量明显增加(P<0.05,P<0.01),LC3Ⅱ/LC3Ⅰ比值升高,p62蛋白表达降低,p-mTOR/mTOR比值降低(P<0.01);与模型组比较,黄连温胆汤组和二甲双胍组大鼠肝组织红色脂滴数量减少,未见明显自噬小体,FPG、FINS和HOMA-IR明显降低(P<0.05,P<0.01),肝组织TC、TG含量减少(P<0.05,P<0.01),LC3Ⅱ/LC3Ⅰ比值降低,p62蛋白表达升高,p-mTOR/mTOR比值升高(P<0.05,P<0.01)。各组大鼠肝组织mTOR mRNA表达差异无统计学意义(P>0.05)。结论黄连温胆汤可改善IR大鼠肝脏脂质蓄积,其机制与上调大鼠肝组织p-mTOR蛋白表达,抑制肝脏自噬有关。

Effects of Huanglian Wendan Decoction on Liver Lipid Accumulation in Rats with Insulin Resistance

Objective To observe the effects of Huanglian Wendan Decoction on liver lipid accumulation in rats with insulin resistance(IR);To explore the mechanism of action from the perspective of autophagy.Methods Totally 50 male SD rats were randomly divided into blank group(10 rats)and modeling group(40 rats).The modeling group was induced with a high-fat and high-sugar diet to IR models.The model rats were randomly divided into model group,Huanglian Wendan Decoction group and metformin group.Each group was given distilled water,Huanglian Wendan Decoction and metformin solution respectively for gavage for 8 weeks.Transmission electron microscopy was used to observe the formation of autophagosomes in rat liver tissues;Oil red O staining was used to observe liver lipid accumulation;ELISA was used to detect fasting plasma glucose(FPG)and fasting insulin(FINS)in rats,and IR index(HOMA-IR)was calculated;GPO-PAP method was used to detect the levels of triacylglycerol(TG)and total cholesterol(TC)in the liver tissue;Western blot was used to detect the expression of LC3,p62,mammalian target of rapamycin(mTOR)and p-mTOR protein in liver tissue;RT-PCR was used to detect the expression of mTOR mRNA in liver tissue.Results Compared with the blank group,the red lipid droplets in the liver tissue of the model group increased significantly,a small amount of autophagosomes were formed;FPG,FINS and HOMA-IR significantly increased(P<0.01),the levels of TC and TG in liver tissue significantly increased(P<0.05,P<0.01),the ratio of LC3Ⅱ/LC3Ⅰ increased,the expression of p62 protein significantly decreased,and the ratio of p-mTOR/mTOR decreased(P<0.01).Compared with the model group,the number of red lipid droplets in the liver tissue of rats in the Huanglian Wendan Decoction group and the metformin group was significantly reduced,no obvious autophagosomes were seen;FPG,FINS and HOMA-IR were significantly reduced(P<0.05,P<0.01),the levels of TC and TG in liver tissue decreased(P<0.05,P<0.01),the ratio of LC3Ⅱ/LC3Ⅰ decreased,the expression of p62 protein increased,and the ratio of p-mTOR/mTOR increased(P<0.05,P<0.01).There was no significant difference in mTOR mRNA expression in liver tissue of the rats among the groups(P>0.05).Conclusion Huanglian Wendan Decoction can improve liver lipid accumulation in IR rats,and its mechanism is related to up-regulating the expression of p-mTOR protein in rat liver tissues and inhibiting liver autophagy.