GLP-1/GIP双受体激动剂替西帕肽改善db/db小鼠代谢相关脂肪性肝病

GLP-1/GIP dual receptor agonist Tirzepatide ameliorates metabolic associated fatty liver disease in db/db mice

目的:比较替西帕肽(Tirzepatide)与利拉鲁肽(Liraglutide)改善db/db小鼠代谢相关脂肪性肝病(metabolic associated fatty liver disease,MAFLD)的效果。方法:以db/db小鼠作为MAFLD模型,21只db/db小鼠分为Model组、Liraglutide组和Tirzepatide组,7只db/m小鼠为Control组。Liraglutide组和Tirzepatide组小鼠每天分别腹腔注射10 nmol/kg的利拉鲁肽或替西帕肽10周。其余两组腹腔注射等量生理盐水。10周后,比较小鼠空腹血糖(fasting blood glucose,FBG)、糖化血红蛋白(glycated haemoglobin A1c,HbA1c)、体重、血清总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、低密度脂蛋白胆固醇(low-density lipoprotein-cholesterol,LDL-C)、高密度脂蛋白胆固醇(high-density lipoprotein-cholesterol,HDL-C)、丙氨酸氨基转移酶(alanine aminotransferase,ALT)及天冬氨酸氨基转移酶(aspartate aminotransferase,AST)的含量。HE及油红O染色比较小鼠肝脏病理学改变以及脂质沉积情况。Western blot及RT-PCR法检测各组小鼠肝脏炎症因子及纤维化介质表达差异,同时检测胰岛素信号通路及糖代谢相关蛋白表达差异。结果:与Model组小鼠相比,Liraglutide组小鼠FBG、HbA1c、体重及TC、TG、LDL-C、ALT、AST分别下降56%、32%、20%、19%、22%、39%、26%及28%,HDL-C升高25%。而Tirzepatide组小鼠FBG、HbA1c、体重及TC、TG、LDL-C、ALT、AST分别下降69%、40%、30%、31%、35%、57%、46%和38%,HDL-C升高了61%。Model组小鼠肝脏表现出明显的肝细胞脂肪变性,呈气球样变及空泡化,肝细胞内聚集大量脂滴,两组干预组小鼠肝细胞脂肪变性以及肝脏脂肪沉积得到改善,替西帕肽的效果最优。Western blot及RT-PCR结果显示,两组药物干预组小鼠炎症因子及纤维化介质表达明显下降,同时,两种药物治疗使胰岛素相关代谢通路蛋白表达增加,并且下调糖代谢相关蛋白表达,替西帕肽改善上述指标的效果优于利拉鲁肽。结论:替西帕肽可通过激活胰岛素相关信号通路,减少糖异生来改善MAFLD小鼠的糖脂代谢紊乱,降低体重,改善肝损伤及肝脏脂肪沉积,延缓肝脏炎症及纤维化,其综合疗效优于利拉鲁肽,可能为MAFLD提供新的治疗方案。

Objective:To compare the therapeutic of Tirzepatide and Liraglutide in improving metabolic associated fatty liver disease(MAFLD)in db/db mice.Methods:Db/db mice were used as the MAFLD model.Total 21 db/db mice were divided into the model group,Liraglutide group and Tirzepatide group,and 7 db/m mice were used as the control group.Mice in Liraglutide and Tirzepatide groups received intraperitoneal injections of 10 nmol/kg of Liraglutide and Tirzepatide daily for 10 consecutive weeks.The other two groups were intraperitoneally injected with the same volume of normal saline.After 10 weeks,the fasting blood glucose(FBG),glycated haemoglobin A1c(HbA1c)and body weight of mice in each group were compared.The levels of serum total cholesterol(TC),triglyceride(TG),low-density lipoprotein-cholestero(l LDL-C),high-density lipoprotein-cholestero(l HDL-C),alanine aminotransferase(ALT)and aspartate aminotransferase(AST)in each group were compared.HE staining and oil red O staining were used to compare the liver pathological changes and lipid deposition in each group.Western blot and RT-PCR were used to detect the expressions of inflammatory factors and fibrosis mediators in the liver tissues of mice in each group.Western blot was used to detect the insulin signaling pathway and glucose metabolism related protein expression differences.Results:Compared with the model group,the levels of FBG,HbA1c,body weight,TC,TG,LDL-C,ALT and AST in the Liraglutide group decreased by 56%,32%,20%,19%,22%,39%,26%and 28%,respectively,while HDL-C increased by 25%.In Tirzepatide group,FBG,HbA1c,body weight,TC,TG,LDL-C,ALT,and AST decreased by 69%,40%,30%,31%,35%,57%,46%and 38%,respectively,while HDL-C increased by 61%.HE staining and oil red O staining showed that the liver of the model group showed obvious hepatocyte steatosis,balloon-like degeneration and vacuolization,and a large number of lipid droplets were accumulated in hepatocytes.The hepatocyte steatosis and liver fat deposition of the two intervention groups were improved,and the effect of Tirzepatide was better than that of Liraglutide.Western blot and RT-PCR results showed that two drug intervention groups markedly reduced the expressions of inflammatory factors and fibrosis mediators,at the same time,the two drugs increased insulin metabolic pathways related protein expression and decreased the glucose metabolism related protein expression,and Tirzepatide was more effective than Liraglutide in improving the above indicators.Conclusion:Tirzepatide can improve glucose and lipid metabolism disorders,reduce body weight,improve liver injury,reduce liver fat deposition,and delay liver inflammation and fibrosis in MAFLD mice by activating insulin-related signaling pathway and reducing gluconogenemia,and its comprehensive efficacy is better than that of Liraglutide,which may provide a new treatment for MAFLD.