Effects of Different Exercises on Skeletal Muscle Fat Deposition in Insulin Resistance Rats and the Role of AMPK-ACC Pathway in Regulating Fatty Acid Oxidation
Objective:To study the effects of aerobic exercise,resistance exercise and aerobic combined resistance exercise on the activities of free fatty acid(FFA)and adenylate activated protein kinase(AMPK),acetyl coenzyme A carboxylase(ACC)and carnitine palmitoyl transferase(CPT1)in skeletal muscle of insulin resistant rats,to investigate the effects of different exercise modes on fat deposition in skele-tal muscle of insulin resistant rats and the role of AMPK-ACC pathway in regulating fatty acid oxidation in skeletal muscle.Methods:Rats fed with high-sugar and high-fat diet were randomly divided into control group(group C),aerobic exercise group(group E),resistance exercise group(group R),aerobic+resistance combined exercise group(group RE).FFA,AMPK,ACC and CPT1 activities of quadriceps femoris were measured after exercise intervention.Results:(1)Compared with group P,the oral glucose tolerance,insulin tolerance in group C were significantly different(P＜0.01)after 13 weeks of high-sugar and high-fat diet,and the area under curve of AUC in group C was significantly different(P＜0.01).There was no significant difference in FBG in group C(P＞0.05);FINS,ISI and HOMA-IR in group C were significantly different from those in group P(P＜0.01).(2)Compared with group C,FFA in serum of group E,group R and group RE had no significant difference(P＞0.05);FFA in quadriceps femoris was significantly decreased(P＜0.01),but there was no signifi-cant difference among exercise groups(P＞0.05).(3)Compared with group C,the activity of AMPK in group E,R and RE increased sig-nificantly(P＜0.01),and the activity of AMPK in group RE increased significantly(P＜0.01);compared with group E and group R,the activity of ACC in group E and group RE decreased,while that in group R increased,but there was no significant difference(P＞0.05),and there was no difference in the activity of CPT1 between exercise groups(P＞0.05).The activity of CPT1 in RE group was significantly higher than that in E group and R group(P＜0.01).Conclusion:(1)The insulin resistance rat model was successfully established after 13 weeks of high-sugar and high-fat diet intervention.(2)Eight cycles of exercise can significantly reduce the fat deposition in skeletal mus-cle of IR rats.The mechanism may be that exercise can significantly increase the activities of AMPK and CPT1 in skeletal muscle of IR rats,enhance the utilization of lipid oxidation and improve insulin resistance;combined aerobic and resistance exercise has more significant effect on fat oxidation than single exercise.(3)Synchronized changes of ACC and CPT1 were not observed in IR rats after 8-cycle exercise inter-vention in different ways.The regulation of fatty acid oxidation in skeletal muscle of IR rats may be independent of AMPK/ACC pathway.whether the regulation of ACC activity is important for reducing fat content needs further study.
万方数据
维普
