Activation Of Lipolytic Enzymes In Mouse Skeletal Muscle By HIIE/MICE

Purpose:Research purpose: Skeletal muscle is the largest energy metabolism organ in the body.The ectopic deposition of skeletal muscle fat caused by obesity is closely related to the occurrence and development of type 2 diabetes.Therefore,reducing ectopic deposition of skeletal muscle fat is a study to prevent the occurrence of type 2 diabetes.direction.Exercise is a safe and effective way to reduce fat,and is gradually being respected.Traditional medium-intensity continuous exercise(MICT)can effectively reduce body fat,and some studies have found that high-intensity intermittent exercise(HIIT)can effectively reduce fat.Our team's previous research found that for adipose tissue,HIIT can promote more visceral fat decomposition than MICT,and is accompanied by increased lipolytic protease activity.Therefore,this study proposes the hypothesis that HIIT is more effective than MICT in reducing skeletal muscle fat,which may be related to increased lipolytic enzyme activity.In this study,C57 BL / 6 mice were used to observe the effect of long-term HIIT / MICT on TG content in skeletal muscle and analyze the activation of skeletal muscle fat hydrolase by HIIE / MICE to explore the possible mechanism of skeletal muscle fat reduction.Provide theoretical basis for the selection of exercise weight loss program.Research method: In this experiment,126 C57 BL / 6J female mice aged 3 weeks were used,6 mice were fed with ordinary feed,and 120 mice were fed with high-fat feed to induce obesity.After 15 weeks,from the mice fed high-fat diets,those who weighed more than 10% of the average weight of mice fed ordinary diets were selected and randomly divided into one-time exercise groups and long-term training groups.These mice were divided into acute exercise group and long-term training group.Acutely exercised mice were subjected to HIIE or MICE exercise intervention,and samples were taken at 0,1h,and 12 h after acute exercise,and named H0,H1,and H12 by time point.,M0,M1,M12,the control group was HFD,and the sample size of each group was 6.Long-term exercise mice were trained in HIIT or MICT exercise 5 times a week for 12 weeks,and samples were taken 48 hours after the last exercise.They were divided into ordinary standard feed group(C27),high-fat control group(HFD27),high-intensity interval training group(HIIT12)and medium-intensity continuous training group(MICT12).Exercise intervention plan: MICT exercise is 45min50%~70% VO2 peakrunning treadmill exercise,HIIT exercise is 90%~110% VO2 peak running treadmill exercise 1 min plus 50%~70% VO2 peak running treadmill exercise 2 min is 1 group,cycle 12 The total distance of MICT and HIIT movement is equal.Triglyceride kit was used to detect the triglyceride content in skeletal muscle tissue of mice in the long-term exercise training group.Acute exercise group mice were tested by Western blot for skeletal muscle fat triglyceride lipase(ATGL),hormone-sensitive lipase(HSL)protein expression and HSLser563,565,and 660 phosphorylation sites and AMP-dependent protein kinase AMPK)and AMPK-Thr172 protein expression levels.Trivariate analysis of skeletal muscle triglyceride content and acute exercise indexes were performed.Research result:1.Compared with the C27 group,the TG content of the skeletal muscle of the HFD27 group was significantly increased(P <0.01);compared with the HFD27 group,the TG content of the skeletal muscle of the MICT12 group and the HIIT12 group was significantly decreased,and the difference was significant(P <0.01 and P <0.05);but there was no significant difference between the HIIT12 group and the MICT12 group(P>0.05).2.Changes of skeletal muscle fat hydrolase expression after one-time exercise(1)After one-time exercise,the expression level of ATGL protein in skeletal muscle of obese mice decreased significantly.The expression level of ATGL protein in skeletal muscle of HFD group was higher than that of M12,H1,and H12 groups,and the difference was extremely significant(P <0.01).The ATGL protein was not activated;At 1hour after exercise,the MICE group was higher than the HIIE group,and the difference was significant(P <0.05).(2)After one-time exercise in obese mice,HSL protein expression in skeletal muscle of the HFD group was significantly higher than that of the HIIE group and the MICE group at 0,1 h after exercise,the difference was significant(P <0.05);it returned to before exercise 12 h after exercise Level,the difference was not significant(P> 0.05).At Oh after exercise,the HSL-ser563 and HSL-ser660 protein expression in skeletal muscle of HFD group was lower than that of MICE group and higher than that of HIIE group;after exercise 0hMICE group skeletal muscle HSL-Ser563 and HSL-ser660 protein expressions were significantly higher than those in HIIE group,and the differencewas significant(P <0.01).The expression of HSL-ser565 protein in skeletal muscle of the MICE group was immediately after exercise,and the HIIE group was significantly higher than that of the HFD group at 0h and 1h after exercise,the difference was significant(P <0.01);the grouping effect was significant(P <0.01),that is,At 0 h after exercise,the MICE group was significantly higher than the HIIE group,and at 1 h after exercise,the HIIE group was significantly higher than the MICE group.(3)AMPK protein was not activated in obese mice after one exercise,and there were significant differences in time-point effect(P <0.01).The expression of AMPK protein in skeletal muscle of HFD group was higher than that of MICE and HIIE groups;0,1 h after exercise The expression of AMPK protein in HIIE group was higher than that in MICE group,and the difference was significant(P <0.01).At 0h after exercise,the expression of AMPK-Thr172 protein in skeletal muscle of MICE group and HIIE group was significantly higher than that of HFD group,the difference was significant(P <0.05);at 1and 12 h after exercise,skeletal muscle AMPK-Thr172 protein in MICE and HIIE group The expression was significantly lower than that in the HFD group,and the difference was significant(P <0.01).At 12 hours after exercise,the expression of AMPK-Thr172 protein in the skeletal muscle of the MICE group was higher than that in the HIIE group,and the difference was significant(P <0.05).Analysis conclusion:1.A high-fat diet may cause ectopic deposition of skeletal muscle fat.Long-term exercise reduces the TG content in skeletal muscle of mice.There is no difference in the effect of MICT and HIIT training on improving TG content in skeletal muscle.2.Within 12 hours after one-time exercise,in the promotion of skeletal muscle HSL activity,the MICE group was superior to the HIIE group.3.In the regulation of HSL-ser565,there may be other regulatory pathways besides AMPK-Thr172.