有氧运动抑制ALCAT1表达并激活FGF21-FGFR1/β-Klotho-PI3K/AKT通路改善心梗诱导的肝损伤

Aerobic Exercise Inhibits ALCAT1 Expression and Activates FGF21-FGFR1/β-Klotho-PI3K/AKT Pathway to Improve Liver Injury Induced by Myocardial Infarction

目的:探讨成纤维生长因子21(fibroblastgrowthfactor 21,FGF21)和心磷脂转移酶1(lysocardiolipinacyltransferase-1,ALCAT1)在有氧运动改善心肌梗死(myocardialinfarction,MI)诱导小鼠肝损伤中的作用。方法:24只8周龄C57/BL6小鼠随机均分为假手术组(S),心梗组(MI),心梗运动组(ME),每组8只。采用左冠状动脉前降支结扎术制备心梗小鼠模型,ME组在术后1周开始进行为期6周的有氧运动干预。运动结束后次日采用心动超声检测心功能,Masson染色检测心肌胶原面积,评价心梗模型。试剂盒检测肝脏天冬氨酸转氨酶(AST)、谷丙转氨酶(ALT)、碱性磷酸酶(ALP)活性,评价肝功能。Masson和SiriusRed染色检测肝脏胶原纤维增生情况,TUNEL染色检测肝细胞凋亡情况。Westernblotting检测肝脏FGF21、FGFR1、β-Klotho、ALCAT1、内质网应激、线粒体自噬和凋亡相关蛋白表达。结果:心梗小鼠心肌CVF%显著增加,心功能显著降低,运动干预后心肌CVF%显著降低,心功能显著改善,表明造模成功。与S组比较,MI组肝脏胶原纤维沉积,血清AST、ALP、ALT活性和肝指数显著升高(P<0.01,P<0.05),FGF21、p-PI3K和AKT蛋白表达代偿性显著升高(P<0.05),ALCAT1、ATF6、IREα、CHOP、GRP78蛋白表达以及LC3Ⅱ/Ⅰ比值和Bax/Bcl-2比值显著升高(P<0.05,P<0.01),β-Klotho、PINK1、Parkin和P62蛋白表达显著降低(P<0.01),TUNEL阳性颗粒数目显著增多(P<0.01);与MI组比较,ME组肝脏胶原纤维沉积显著减少,血清AST、ALP和ALT活性显著降低(P<0.01),FGF21、FGFR1、β-Klotho、p-PI3K和AKT蛋白表达显著升高(P<0.01),ALCAT1、ATF6、IREα、CHOP、GRP78蛋白表达以及LC3Ⅱ/Ⅰ比值和Bax/Bcl-2比值显著降低(P<0.05,P<0.01),PINK1、Parkin和P62蛋白表达显著升高(P<0.05,P<0.01),TUNEL阳性颗粒数目显著减少(P<0.01)。结论:心梗可诱导肝脏发生内质网应激、线粒体自噬流异常和肝细胞凋亡,导致肝损伤。有氧运动干预可抑制心梗小鼠肝脏ALCAT1表达,激活FGF21-FGFR1/β-Klotho-PI3K/AKT通路,抑制内质网应激和线粒体自噬流异常,减轻肝细胞凋亡,改善肝功能。推测FGF21和ALCAT1可能是有氧运动抑制心梗诱导肝损伤的重要靶分子。

Objective:To investigate the role of fibroblast growth factor 21(FGF21)and lysocardiolipinacyltransferase-1(ALCAT1)in improving liver injury induced by myocardial infarction(MI)in mice.Methods:Twenty-four 8-week-old C57/BL6 mice were randomly divided into sham operation group(S),myocardial infarction group(MI)and myocardial infarction exercise group(ME),8 mice in each group.Left anterior descending ligature(LAD)was used to make MI model,and the ME group taken 6-week aerobic training after 1 week of operation.After training,the echocardiography was used to detect the cardiac function and Masson staining was used to detect the myocardial fibrosis.The liver function was evaluated by the activities of AST,ALT and ALP which were detected by kit.Masson and Sirius red staining were used to detect collagen proliferation and TUNEL staining was used to detect hepatocyte apoptosis.The expressions of FGF21,FGFR1,β-Klotho,ALCAT1,endoplasmic reticulum stress(ERs),mitochondrial autophagy and apoptosis related proteins were detected by Western blotting.Results:The CVF%was significantly increased and the cardiac function was significantly decreased in MI group,but the CVF%was significantly decreased and the cardiac function was significantly improved in ME group.Compared with S group,the deposition of liver collagen,AST,ALP,ALT and liver index in MI group were significantly increased(P<0.01,P<0.05),the protein expressions of FGF21,p-PI3K,AKT,ALCAT1,ATF6,IREα,CHOP,GRP78,LC3Ⅱ/Ⅰand Bax/Bcl-2 were significantly increased(P<0.05,P<0.01),but the protein expressions ofβ-Klotho,PINK1,Parkin and P62 were significantly decreased(P<0.01),the TUNEL positive granules was increased significantly(P<0.01).Compared with MI group,the deposition of liver collagen,AST,ALP and ALT in ME group were significantly decreased(P<0.01),and the protein expression of FGF21,FGFR1,β-Klotho,p-PI3K,AKT,PINK1,Parkin and P62 in liver were significantly increased(P<0.05,P<0.01).ALCAT1,ATF6,IREα,CHOP,GRP78 protein expression and LC3Ⅱ/Ⅰ,Bax/Bcl-2 protein ratio,TUNEL positive granules were decreased significantly(P<0.05,P<0.01).Conclusion:Myocardial infarction can induce endoplasmic reticulum stress,mitochondrial autophagy disorder and hepatocyte apoptosis in the liver,which lead to abnormal liver function.Aerobic exercise downregulates the expression of ALCAT1 and activates FGF21-FGFR1/β-Klotho-PI3K/AKT pathway,inhibit ERstress,mitochondrial autophagy disorder and hepatocyte apoptosis,and improve liver function.It is speculated that FGF21 and ALCAT1 may be important target molecules of aerobic exercise in inhibiting liver injury induced by myocardial infarction.