| Objective: NAFLD is the most common chronic liver disease that endangers human health,and inflammation is a key pathological event of NAFLD.Mi RNA-122 is a mi RNA specifically expressed in the liver.Multiple studies have shown that the deletion of mi RNA-122 genes seriously affects liver lipid metabolism,leading to liver microstructure degradation and inflammatory response.The inhibition of mi RNA-122 leads to inflammation,necrosis,steatosis,and fibrosis.In NAFLD patients and animal models,mi RNA-122 expression in liver tissue is dysregulated.Exercise training is a non pharmacological treatment for NAFLD,and exercise may prevent the development of NAFLD by reducing liver inflammation.And relevant studies have shown that exercise may improve lipid metabolism by regulating the expression of mi RNA-122 in the liver.However,further research is needed on the mechanism of mi RNA-122 in NAFLD inflammation and its role in the influence of exercise on NAFLD.This study established a high-fat diet induced NAFLD mouse model,combined with 8-week endurance exercise intervention,to study the effect of endurance exercise on mi RNA-122 and explore the role of exercise and mi RNA-122 on the inflammatory response of NAFLD.Provide theoretical basis for research on the prevention and treatment of NAFLD through exercise.Methods: 1.48 7-week-old C57BL/6 male mice were randomly divided into standard diet group(16 mice fed with normal diet)and high-fat diet model group(32mice fed with high-fat diet)after adaptive feeding for 1 week.After 12 weeks,20% of the average body weight of the mice in the normal diet group was selected as the criteria for the success of the obese mice model.Sixteen mice were selected from the high-fat diet group and randomly divided into the high-fat control group(HFD)and the high-fat endurance exercise group(HFE).The mice in the standard diet group were randomly divided into the normal control group(NC)and the simple endurance exercise group(NE),with 8 mice in each group.2.The NE and HFE groups underwent 8-week moderate intensity treadmill endurance training: one week of treadmill adaptation training was conducted during the advanced behavior period before the exercise intervention,with a treadmill speed of 5m/min and a duration of 10 minutes,to familiarize the mice with the environment and process of treadmill training;Subsequently,moderate intensity treadmill training was conducted with a treadmill speed of 12m/min and a duration of 60 min for 4consecutive weeks(with two days off on Saturdays and Sundays);In the fifth week,the running speed increased to 14m/min,with a duration of 60 minutes,for 4consecutive weeks(two days off on Saturdays and Sundays).3.NAFLD model construction criteria: liver tissue oil red O staining,liver lipid content>5% as the criteria for successful modeling,in which liver lipid content<33%is mild steatosis,>67% is severe steatosis,and between them is moderate steatosis.Then combined with the results of H&E staining,the liver pathological damage was evaluated according to the semi-quantitative scoring system: steatosis,hepatocyte ballooning,hepatocyte hypertrophy and inflammation.4.Experimental method:1)Weigh the body weight and liver weight of mice and calculate the liver index(liver index=liver weight(g)/body weight(g)× 100%);2)Detection of serum AST,ALT,TG,TC,HDL-C and LDL-C in mice;3)Frozen section of liver tissue,oil red O staining,observation of liver lipid content;4)The paraffin section of liver tissue was stained with H&E to observe the pathological damage of mouse liver;5)Detection of liver mi RNA-122,PTP1 B,NF-κB,TNF-α,IL-1β,IL-6 expression by real-time fluorescence quantitative PCR;6)Western Blot analysis of liver PTP1 B and NF-κB,TNF-α,IL-1β,IL-6 protein expression.5.All data are represented by mean ± standard deviation(Mean ± SD).SPSS24.0software is used to process the data.The statistical method is two-factor analysis of variance,with p<0.05 as the standard of significant difference and p<0.01 as the standard for extremely significant difference.Results: 1.Compared with NC group,the body weight and liver weight of mice in HFD group increased significantly(p<0.01),but the liver index did not change significantly(p>0.05).Compared with HFD mice,the body weight of HFE mice was significantly lower(p<0.01),the liver weight was significantly lower(p<0.05),and the liver index had no significant change(p>0.05).2.Compared with NC group,the serum AST and ALT content was significantly higher(p<0.05).Compared with HFD mice,the serum AST and ALT contents of HFE mice were significantly decreased(p<0.05).3.Compared with NC group mice,the serum TC and LDL-C levels of HFD group mice were significantly higher(p<0.01),TG levels were significantly higher(p<0.05),and HDL-C levels were significantly lower(p<0.05).Compared with HFD mice,the serum TC,LDL-C and TG levels of HFE mice were significantly lower(p<0.05),while HDL-C levels were significantly higher(p<0.05).4.The results of oil red O staining showed that the liver of mice in HFD group showed mild fatty degeneration.Compared with NC group,liver fat content in HFD group was significantly higher(p <0.01).After 8 weeks of exercise intervention,the liver fat content of mice decreased significantly(p <0.01).The results of H&E staining showed that the liver of mice in HFD group showed diffuse fatty changes,accompanied by ballooning and slight intralobular inflammation,and its NAS score was significantly higher than that in NC group(p <0.01).After 8 weeks of endurance exercise,the liver steatosis of mice was reduced,and its NAS score was significantly reduced(p<0.01).5.Compared with NC group,the expression of mi RNA-122 in HFD group was significantly decreased(p<0.05),and the expression of PTP1 B,NF-κB,IL-1β,IL-6,TNF-α m RNA was significantly increased(p<0.01).Compared with HFD mice,the expression of mi RNA-122 in HFE mice increased significantly(p<0.05).The expression of PTP1 B and IL-6 m RNA was significantly decreased(p<0.01),and the expression of NF-κB and TNF-α m RNA was significantly decreased (p<0.05).6.Compared with NC group,the expression of PTP1 B protein in the liver of mice in HFD group was significantly higher(p<0.05),The expression of NF-κB,TNF-α,IL-1β,IL-6 protein was significantly increased(p<0.01).After 8 weeks of treadmill endurance training intervention,liver PTP1 B,NF-κB protein expression of mice in HFE group decreased significantly(p<0.05),TNF-α,IL-1β,IL-6 protein expression decreased significantly(p<0.01).Conclusion: High-fat diet induces the pathological development of NAFLD in mice,leading to steatosis and disruption of liver inflammatory factors in the liver.Endurance exercise improves these pathological changes induced by a high-fat diet and inhibits the pathological process of NAFLD.This may be related to the upregulation of mi RNA-122 expression in the liver and the downregulation of PTP1 B expression. |
