Different Effects Of Exercise On CD36 And FATP1 And GLUT4 And Their Related Molecules In Gastrocnemius And Hippocampus Of Obese Rats

Background and Objectives:The global epidemic of obesity is now recognized as one of the most important public health problems facing the world today.Human and animal model studies have shown that reduced expression,blocked translocation and reduced activity after fusion with the plasma membranes of glucose and lipid transport proteins as well as its not fusing with the plasma membranes after translocation are involved in the occurrence and progression of diseases such as obesity and insulin resistance.Regular exercise is one of the most effective ways to reduce body fat and prevent obesity.Studies have found that moderate exercise can improve the o verall metabolism of obese individuals,and that the improvement of metabolic disorders is associated with the changes of exercise-induced glucose and lipid transport proteins content and/or subcellular localization.As the presence of blood-brain barrier and the structural and functional differences in peripheral and central tissues,glucose and lipid metabolism in peripheral and central tissues is different,And it may also possible that the need for glucose and lipid metabolism in skeletal muscle as a motor performerand hippocampus which does not participate in exercise execution is differentin the state of obesity and during exercise.It is speculated that exercise training may have different impacts on glucose and lipid transport proteins and their related molecules in skeletal muscle and hippocampus of obese rats induced by high fat diet.The purpose of this paper is to observe the effects of 8-week aerobic endurance exercise on body weight,body composition,blood lipid and blood glucose in obese rats,and to discuss whether these changes are related to the alterations in glucose and lipid transport proteins and related molecules.Another purpose of this paper is to observe and explore the effects and differences of exercise on CD36,FATP1,GLUT4,AMPK-ACC and PI3K-Akt signaling pathways in gastrocnemius and hippocampus of obese rats.METHODS:In this study,7-week-old male SD rats as the research object,after the initial adaptive feeding,the rats were randomly divided into normal diet group(C,n=20)and high fat diet group(H,n=50).At the end of the 8th week,the rats in group C were randomly and equally divided into normal diet sedentary group(NC,normal diet,n=10)and normal diet exercise group(N E,normal diet,n=10);The rats in group H whose body weight values were above the mean value plus 1.4 times the standard deviation of the body weights of rats in group C were picked out and then randomly divided into obese sedentary group(OC,high fat diet,n=10)and obese exercise group(O E,high fat diet,n=10).Rats in group NC and group OC were without exercise training.Rats in group N E and group OE were performed an 8-week moderate intensity treadmill exercise training after being adapted to the treadmill for a week.The body mass and food intake were monitored during the experiment.The body composition of rats was measured by dual energy X-ray bone density instrument after exercise intervention.The rats were fasted overnight 24 hours after the last exercise training,and then anaesthe tized with 10% chloral hydrate.Blood samples were collected from the inferior vena cava,and gastrocnemius were rapidly removed from the left hind limbs,and hippocampal tissues were isolated in ice bath.Serum TC,TG,LDL-C and glucose levels in rats were detected by a fully automatic biochemical analyzer.The expressions of CD36,FATP1,GLUT4,CREB,AMPKα,p-AMPKα,ACC,p-ACC,PI3 K p85,p-PI3 K p85,Akt and p-Akt in gastrocnemius and hippocampus were detected by Western blotting.RESULTS :(1)Monitoring results of body mass,food intake and energy intake.A significantly increase in body mass occurred in the H group compared with the C group(P<0.01).Body mass(P<0.01)and energy intake(P<0.05,P<0.01)were markedly higher,but food intake was notably lower(P<0.01)in the OC group when compared with the NC group.Body mass(P<0.01),food intake(P<0.05,P<0.01)and energy intake(P<0.05,P<0.01)were appreciably lower in the OE group than those in the OC group after 8-week exercise intervention.(2)Detecting results of body composition.Compared with the NC group,whole-body adipose tissue mass and whole-body fat percentage increased obviously(P<0.01),and whole-body muscle tissue mass and whole-body muscle percentage decreased significantly(P<0.01),but whole-body bone mineral density increased markedly(P<0.01)in the OC group.Whole-body adipose tissue mass and whole-body fat percentage were significantly lower(P<0.01),whole-body muscle tissue mass and whole-body muscle percentage were significantly higher(P<0.01)in the O E group than in the OC group,but whole-body bone mineral density did not changed markedly(P>0.05).Whole-body bone mineral density in the NE group was notably higher than in the NC group(P<0.05).(3)Detecting results of serum lipids and glucose.Compared with the NC group,serum TG and glucose levels were significantly higher(P<0.05),and serum TC level increased but there was no statistical significance(P>0.05)in the OC group.Serum TG level was significantly lower(P<0.05),and serum TC and glucose levels decreased but without statistical significance in the O E group when compared with the OC group(P>0.05).(4)Detecting results of glucose and lipid transport proteins and their related molecules in gastrocnemius.Compared with the NC group,the protein expressions of CD36,FATP1 and GLUT4 did not change significantly(P>0.05)but CREB protein expression decreased significantly(P<0.05);The phosphorylation levels of AMPKα and ACC were significantly lower(P<0.01);The protein expressions of PI3 K p85 and Akt and the phosphorylation level of PI3 K p85 did not change significantly(P>0.05),but the phosphorylation level of Akt decreased notably(P<0.01)in the OC group.Compared with the OC group,the protein expressio ns of CD36 and FATP1 were no significant change(P>0.05),but the protein expressions of GLUT4 and CREB increased notably(P<0.01);The phosphorylation levels of AMPKα and ACC were significantly higher(P<0.01);The protein expressions of PI3 K p85 and Akt and the phosphorylation level of PI3 K p85 were no significant change(P>0.05),but the phosphorylation level of Akt increased notably(P<0.01)in the OE group.Compared with the NC group,the phosphorylation level of AMPKa had a significant increase(P<0.01)in the N E group.(5)Detecting results of glucose and lipid transport proteins and their related molecules in hippocampus.The protein expressions of CD36 and FATP1 increased significantly(P<0.05)in the OC group when compared with the NC group.Compared with the NC group,the protein expression of GLUT4 increased but there was no statistical significance(P>0.05),and the protein expressions and the phosphorylation levels of AMPKα,ACC and PI3 K p85 were no significant changes(P>0.05)in the OC group.Compared with the OC group,the protein expressions of CD36,FATP1,GLUT4 and Akt did not change significantly(P>0.05),the protein expressions and the phosphorylation levels of AMPKα,ACC and PI3 K p85 had no notable changes(P>0.05)in the O E group.Conclusions:(1)8-week aerobic endurance exercise could result in reduced body mass,decreased body fat content,increased lean body mass,improved blood lipid disorders and moderately decreased blood glucose level in obese rats.(2)8-week aerobic endurance exercise could change the activation level of the AMPK-ACC signaling pathway in obese rat gastrocnemius muscle.In addition,exercise intervention could induce the increase of GLUT4 and CREB protein expressions accompanied by the up-regulation of Akt phosphorylation level in gastrocnemius of obese rats,which indicated that the alterations in Akt phosphorylation levels were associated with the changes,induced by exercise intervention,in the protein expression of GLUT4 and CREB in gastrocnemius of obese rats.(3)The protein expressions of CD36 and FATP1 significantly increased in hippocampus of obese rats,indicating that high fat diet induced metabolic changes could influence the expressions of fatty acid transport proteins in hippocampus.8-week aerobic endurance exercise could not significantly alter the protein expressions of GLUT4,CD36 and FATP1 and their related molecules in hippocampus of obese rats.(4)High fat diet induced obese and aerobic endurance exercise existed different effects on glucose and lipid transport proteins and their related molecules in gastrocnemius and hippocampus of obese rats.