有氧运动对非酒精性脂肪性肝病大鼠肝脏脂质沉积的影响及作用机制探讨

Aerobic exercise reduces hepatic lipid deposition in non-alcoholic fatty liver disease

目的观察有氧运动对非酒精性脂肪性肝病(NAFLD)大鼠肝脏脂质沉积及单酰甘油O-酰基转移酶1(MGAT1)信号通路的影响,为NAFLD患者康复干预提供参照依据。方法选取雄性SD大鼠喂饲含45%脂肪的高脂饲料6周。待证实大鼠已诱发NAFLD后,采用随机数字表法将其分为运动组、安静组及饮食调整组,运动组及安静组大鼠均继续给予高脂饮食,运动组同时辅以8周有氧运动,饮食调整组则恢复正常饮食并保持安静状态。于干预8周后利用HE染色法检测各组大鼠肝组织脂质蓄积并计算肝脏脂肪变性指数,采用Western blot法检测大鼠肝脏MGAT1及过氧化物酶体增殖物激活受体γ(PPARγ)蛋白表达水平。结果经8周干预后与安静组比较,发现运动组和饮食调整组大鼠肝脏脂肪变性指数[分别为(31.5±4.7)%和(25.1±3.9)%]均明显下降(P<0.05),运动组肝脏MGAT1蛋白表达量(0.46±0.15)明显降低(P<0.05),PPARγ蛋白表达量(2.16±0.37)明显升高(P<0.05),饮食调整组肝脏MGAT1蛋白表达量(0.89±0.26)无显著变化(P>0.05),PPARγ蛋白表达量(1.78±0.35)明显升高(P<0.05);与饮食调整组比较,运动组大鼠肝脏脂肪变性指数明显升高(P<0.05),肝脏MGAT1蛋白表达量明显降低(P<0.05),PPARγ蛋白表达量无显著变化(P>0.05)。结论有氧运动可显著改善NAFLD大鼠肝脏脂质沉积,其作用机制可能与抑制MGAT1信号通路有关;有氧运动可能是NAFLD患者康复干预的重要手段。

Objective To observe any effect of aerobic exercise on lipid deposition in the liver and monoacylglycerol O-acyltransferase 1(MGAT1)signaling in non-alcoholic fatty liver disease(NAFLD).Methods Male Sprague-Dawley rats were fed a 45%diet fat for 6 weeks,after which they were confirmed to have NAFLD.The rats were then randomly divided into an exercise group,a sedentary group and a diet adjustment group.The exercise and sedentary groups remained on the high-fat diet,but the exercise group underwent 8 weeks of aerobic exercise,while the diet adjustment group returned to a normal diet without any exercise.After the intervention,lipid accumulation in liver tissues was detected by hematoxylin-eosin staining and hepatic steatosis indices were calculated.Liver MGAT1 and the expression of peroxisome proliferator activated receptorγ(PPARγ)protein were detected using western blotting.Results Liver steatosis indices in the exercise and the diet adjustment groups had decreased significantly after the eight weeks.The expression of MGAT1 protein had decreased significantly in the exercise group and the expression of PPARγprotein had increased significantly.Compared with the sedentary group,no significant changes were observed in the expression of MGAT1 protein in the livers of the diet adjustment group,though their average PPARγprotein expression had increased significantly.Compared with the diet adjustment group,the average liver steatosis index had increased significantly in the exercise group,but the expression of MGAT1 protein had decreased significantly.Conclusions Aerobic exercise can significantly improve liver lipid deposition in NAFLD,at least in rats.The mechanism may be related to inhibition of the MGAT1 signal pathway.Aerobic exercise may be a rehabilitation intervention for NAFLD patients.