| Objective: NAFLD refers to metabolic liver injury diseases caused by non-alcoholic factors,such as high-fat or high-sugar diets caused by excessive accumulation of fat in liver cells and insulin resistance.In recent years,studies have found that autophagy can play a regulatory role in different degrees of liver damage,but its related signaling pathways have not been completely revealed.Exercise,as a healthy intervention,can activate autophagy to improve liver fibrosis.However,the role and mechanism of different forms of exercise in improving the progression of NAFLD and fibrosis need to be further studied.Therefore,we established a mouse model of NAFLD by feeding a high-fat diet.Exercise intervention was conducted to further explore the role of autophagy and its related PI3K/AKT/m TOR pathway in the progression of NAFLD liver fibrosis.The effect and mechanism of moderate-intensity aerobic training and high-intensity interval training activating autophagy in improving liver fibrosis in mice with NAFLD provide new ideas for exploring the prevention and control methods and target screening of liver fibrosis.Methods: In this experiment,40 three-week-old male C57BL/6J mice were randomly divided into ordinary feed feeding group(n=12)and high-fat feed feeding group(n=28)and were given ordinary feed and 60% fat ratio high-fat feed.Respectively,for 18 weeks of model feeding,and then two mouse livers were randomly selected for hematoxylin-eosin(HE)staining,oil red O staining in each group,observing liver steatosis and fat deposition,and judge whether the molding is successful.The mice who successfully modeled were randomly divided into M(NAFLD model group,n=8)and continued to be fed high-fat feed,A(moderate aerobic exercise group,n=8)group,H(high-intensity interval exercise group,n=8)group,and the exercise group was subjected to 8 weeks of exercise intervention.After the intervention,all the experimental mice were dislocated and sacrificed,and the serum and liver tissues of mice were collected respectively,and biochemical indexes related to liver function were detected.Liver steatosis was observed by HE staining,lipid deposition degree was observed by oil red O staining,fibrosis degree of liver was judged by masson staining,and activation of hepatic stellate cells was observed by α-SMA immunohistochemical staining.q RT-PCR detects genetic changes associated with liver fibrosis;western blot analyzed the expression and changes of proteins associated with the lipid metabolism,autophagy,and PI3K/AKT/m TOR signaling pathway.Results: 1.Body weight and liver wet weight: Compared with the group of ordinary feed feeding,the body weight and liver wet weight of mice in M group fed with continuous high-fat feed were significantly increased;After 8 weeks of exercise intervention,the body weight and liver wet weight of mice in the two different exercise groups decreased significantly,and there was no significant difference between exercise groups.2.Liver morphological changes: The HE staining and oil red O staining showed significant steatosis and lipid deposition in the livers of mice in group M,and the steatosis and lipid deposition were improved to varying degrees after the two exercise interventions,with medium intensity aerobic exercise interventions were better.The results of Masson staining and α-SMA immunohistochemical staining showed that the livers of mice in group M had significant liver collagen deposition compared with group C α-SMA-positive area was significantly increased,and exercise was significantly improved.3.Serum biochemical indexes: Compared with group C,the serum TG,ALT and AST of mice in group M were significantly increased,indicating M Group mouse hepatocytes were damaged.After the exercise intervention,serum TG,ALT and AST in the A and H groups showed significant decreases compared with those in the M group.4.qRT-PCR analysis: the liver fibrosis-related genes COL1α1 and COL3α1 were detected by q RT-PCR,the results showed that the mice in the M group fibrotic gene transcription in liver tissues was significantly increased.After 8 weeks of exercise intervention,both exercises downregulated the transcription of liver fibrosis genes in liver tissues of mice with fatty liver,and there was no significant difference between exercise groups.5.Western blot analysis: Compared with group C,the expression of autophagy-related proteins Beclin1,LC3-II/LC3-I in liver tissue autophagy in the M group decreased significantly,and p62 increased significantly,indicating that it was indicated that it was significantly reduced Group M mice were inhibited from autophagy in liver cells,and the expression of lipid metabolism-related proteins was abnormal.After 8 weeks of exercise intervention,the liver PI3K/AKT/m TOR of mice in exercise group A and group H The upstream related signaling pathways of autophagy are inhibited,autophagy flux is activated,and liver lipid metabolism is improved.Conclusion: The liver of long-term high-fat fed NAFLD mice showed fibrosis progression,and the damage mechanism may be related to the downregulation of autophagy and activation of the PI3K/AKT/m TOR pathway.Moderate-intensity continuous training was more effective in improving liver steatosis,lipid accumulation and abnormal lipid metabolism.Different forms of training could improve liver fibrosis in mice with NAFLD,and there was no significant difference in the improvement effect between moderate-intensity continuous training and high-intensity interval exercise training. |
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