| Objective: The purpose of study was to explore the effects and possible mechanism of the aerobic exercise on cardiomyocyte autophagy in nonalcoholic fatty liver disease rats. Methods: 50 healthy male SD rats of 8 weeks, were randomly divided into normal control group(n=20) and NAFLD model group(n=30).The normal control group were fed by ordinary diet and model group were fed by high-fat diet.At 8 weeks, 10 rats of each group were randomly selected as C8 and M8 group. The nonalcoholic fatty liver rat model was established by contrast detection. Then the remaining model group were randomly divided into: model control group(M16 group, n=10) and exercise-model group(EM group, n=10).The remaining normal control group were marked as C16 group.The C16 group were fed by ordinary diet and M16 and EM groups were fed by high-fat diet. The EM group underwent no load aerobic swimming(60min/d?6d/w?8w)until the end of the 16-week experiment.Serum TG,TC ALT, AST were measured with autobiochemical analyzer. Pathological change of liver tissue was observed after HE staining. The ultrastructural organization of myocardium was observed by transmission electron microscope.The determination of FFA,MDA,SOD and TNF-? were tested by the ELISA method. The protein expressions of Beclin-1 and NF-?B were tested by Western bloting.Results: 1. The liver cells had no obvious fatty denaturation in C8 group, but 8 of 10 were found fatty degeneration of liver cells in M8 group, compared with C8 group, hepatocyte steatosis was aggravating significantly.The hepatocyte steatosis in C16 and M16 group were more serious than groups in 8 weeks. 2 of 10 were found a small amount of fatty degeneration in liver cells in C16 group. All the rat liver cell fatty degeneration is obviously visible in M16 group. 6 of 9 were found fatty degeneration in liver cells in EM group. Compared with C16 group, hepatocyte steatosis was aggravating significantly in M16 group and EM group.Compared with M16 group, hepatocyte steatosis was decreased in EM16 group. 2. Compared with C8 group, serum AST, ALT, TC and TG in M8 group were increased significantly in M8 group. Compared with C16 group, serum ALT, AST, TC, TG were increased obviously in M16 group. In contrast, serum AST, ALT, TC and TG in EM group were decreased significantly compared with M16 group.3.Under the electron microscope, there were some thin and short swelling myocardial mitochondria and no autophagosome observed in M16 group. In EM group, structure of myocardial cell nucleus and mitochondria were normal but some ridges in mitochondria were swelling. And there were some autophagic vacuoles observed. 4.The myocardial MDA and TNF-? contents were significantly higher than that of C16 group, SOD content was reduced; Compared with M16 group, myocardial FFA,MDA and TNF-? contents of EM group were lower, SOD content was increased, but there was no significant difference. 5.Compared with C16 group, the protein expression of myocardial Beclin-1 were obviously decreased in M16 group; the protein level of myocardial Beclin-1 in EM group was significantly higher than that in M16 group. The protein expression of myocardial NF-?B in M16 group was obviously higher than that in C16 and EM groups.Conclusions: 1. NAFLD model by 8 weeks of high-fat diet is successful and the degree of fatty liver of NAFLD rats are added with the extension of time.2. High fat-diet for 16 weeks reduce cardiomyocyte autophagy level of NAFLD rats, showing that myocardial cell injury aggravated 3.8 weeks aerobic swimming exercise can significantly improve the level of cardiomyocyte autophagy in NAFLD rats, relieve myocardial cell injury. Aerobic exercise has a protective effect on reducing myocardial injury of NAFLD. |
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