运动及饮食干预对非酒精性脂肪性肝炎小鼠肝脏自噬的影响研究

Effect of exercise and dietary intervention on hepatic autophagy in mice with non-alcoholic steatohepatitis

目的探讨运动及饮食干预对非酒精性脂肪性肝炎(NASH)小鼠肝脏组织自噬活性的影响。方法C57BL/6小鼠随机分为对照组、模型组、跑台运动干预(运动)组、饮食干预(饮食)组、联合干预(联合)组;对照组、模型及运动组给予高果糖饲料,饮食组及联合组前12周给予高果糖饲料喂养,后8周改喂普通饲料;运动及联合组进行8周跑台运动。HE染色观察小鼠肝脏病理变化及计算非酒精性脂肪性肝病活动性评分(NAS);全自动血液生化分析仪检测血清血脂、肝功指标;qRT-PCR法和Western blot法检测自噬相关基因及蛋白相对表达量,并与肝脏病理形态指标进行相关性分析。结果与对照组比,模型组体质量、肝指数、TC、TG、ALT、AST、LDL-C、NAS、p62 mRNA及蛋白相对表达量均增高(均P<0.05),Beclin-1 mRNA及蛋白表达量、HDL-C均降低(均P<0.05);与模型组比,运动组、饮食组及联合组小鼠体质量、TC、TG、AST、ALT、LDL-C、NAS、p62 mRNA及蛋白相对表达量均显著降低(P<0.05),Beclin-1 mRNA及蛋白相对表达量、HDL-C均增高(均P<0.05);与联合组相比,运动组和饮食组体质量、TG、AST、ALT、NAS、p62 mRNA及蛋白相对表达量均显著增高(均P<0.05),运动组TC、肝指数均显著增高(均P<0.05),微管相关蛋白轻链3(Lc3)-II蛋白相对表达量显著降低(P<0.05),饮食组HDL-C、LDL-C、Lc3-II mRNA相对表达量均显著降低(均P<0.05)。NAS与Beclin-1 mRNA表达量呈正相关(P<0.05),与p62 mRNA表达量负相关(P<0.05)。结论高果糖饮食导致NASH小鼠肝脏出现大量脂质沉积和炎性浸润,自噬活性抑制,而运动及饮食干预可促进Beclin-1 mRNA及蛋白表达,抑制p62 mRNA及蛋白表达,从而激活肝脏自噬,延缓NASH疾病进展。

Objective To research how dietary and exercise changes affect the autophagic activity of liver tissue in mice with non-alcoholic steatohepatitis(NASH).Methods C57BL/6 mice were randomly assigned to the control,model,exercise,diet and combined intervention groups.The control group,model and exercise group were fed normal and high fructose diets,respectively.The diet group and combined group were fed high fructose diets for the first 12 weeks,then switched to normal diets for the last 8 weeks.The exercise and combined group run the platform for 8 weeks.HE staining was used to observe the pathological changes in the liver of mice and to calculate the non-alcoholic fatty liver disease activity score(NAS).Serum lipids and liver function indices were measured by an automatic blood biochemistry analyzer;qRT-PCR and Western blot were used to detect the relative expression of autophagy-related genes and proteins and were correlated with the morphological indexes of liver pathology.Results Body mass,liver index,TC,TG,AST,ALT,LDL-C,NAS,p62 mRNA and protein expression in the model group were higher than in the control group,while Beclin-1 gene and protein expression and HDL-C were lower(all P<0.05).In comparison to the model group,body mass,TC,TG,AST,ALT,LDL-C,NAS,p62 mRNA and protein expression were all significantly lower in the exercise and diet group,while Beclin-1 gene and protein expression,as well as HDL-C,were higher(all P<0.05).Body mass,TG,AST,ALT,NAS,p62 mRNA,and protein expression were significantly higher in the diet and exercise groups compared to the combined group(all P<0.05),TC and liver index were significantly higher in the exercise group(P<0.05),relative Lc3-II protein expression was significantly lower(P<0.05),and HDL-C,LDL-C and Lc3-II mRNA expression were lower in the diet group(P<0.05).NAS was negatively correlated with p62 mRNA expression and positively correlated with Beclin-1 mRNA expression(P<0.05).Conclusion A high-fructose diet resulted in significant lipid buildup,inflammatory infiltration,and suppression of autophagy in the livers of NASH animals.Exercise and dietary changes increased Beclin-1 mRNA and protein expression while decreasing p62 gene and protein expression,activating hepatic autophagy and slowing the progression of NASH illness.