Effect Of Aerobic Exercise And Diet Intervention On Skeletal Muscle Lipid Metabolism Of Rats With Insulin Resistance

Obejective To observe the effect of aerobic exercise and/or standard diet on the expression level of intramyocellular triglyceride (IMTG) and lipoprotein lipase (LPL),uncoupling protein 3 (UCP3),superoxide dismutase (SOD) and Malondialdehyde (MDA) in keletal muscle of insulin resistant (IR) rats fed with high fat. And to discuss the effects of aerobic exercise and/or standard diet on skeletal muscle lipid metabolism and the development of insulin resistant of rats and its possible mechanism.Methods 40 male SD rats were modeled into IR rats by high fat diet for 8 weeks, while the 10 rats of control group were fed with standard diet. Then the 40 IR rats were randomly divided into 4 groups:DIO Group were given high fat diet for 8weeks; DIO-exercise Group and DIO-standard diet Group were respectively treated by aerobic exercise and standard diet; DIO-exercise&standard diet Group were treated by both aerobic exercise and standard diet.The groups were recorded at the beginning and the end of the treatment, including Fasting blood glucose (FBG),Fasting insulin (FIN) and OGTT; and insulin sensitivity index(ISI) was calculated. Put rats to death after the completion of the 8-week training,and then detect the level of IMTG,LPL,SOD and MDA of skeletal muscles; Western blot was used to determine the expressions of UCP3.Results 1. The body weight was obviously higher (P<0.01) and ISI was obviously lower (P<0.01) in the DIO Group than the control group after feeding high fat diet for 8 weeks.2. The body weight, IMTG and MDA was obviously higher (P<0.01) and ISI, LPL, SOD and UCP3 was obviously lower (P<0.05 or P<0.01) in the DIO Group than the control group after feeding high fat diet for another 8 weeks.3. After aerobic exercise and/or standard diet treatment for 8 weeks, the difference of ISI was not statistically significant between DIO-standard diet Group, DIO-exercise&standard diet Group and control group (P>0.05). The difference of FBG,FIN was not statistically significant between DIO-exercise Group, DIO-standard diet Group, DIO-exercise & standard diet Group and control group (P>0.05).4. The IMTG, MDA was obviously lower (P<0.01) and SOD, UCP3 was obviously higher (P<0.01 or P<0.05) in the DIO-exercise Group than the DIO Group, but there is no significant difference between DIO-exercise and DIO Group (P>0.05). And there is no significant difference in the MDA, SOD and UCP3 contents between the DIO-exercise and the control group (P>0.05).5. The IMTG, MDA was obviously lower (P<0.01) in the DIO-standard diet Group than the DIO Group, but there is no significant difference in the LPL, SOD and UCP3 between DIO-standard diet Group and DIO Group (P>0.05). And there is no significant difference in the MDA, SOD and UCP3 content between the DIO-exercise and the control group (P>0.05).6. The IMTG, MDA was obviously lower (P<0.01) and LPL, SOD, UCP3 was obviously higher (P<0.01) in the DIO-exercise&standard diet Group than the DIO Group, but there is no significant difference between DIO-exercise&standard diet Group and DIO Group (P>0.05). And there is no significant difference in these indexes between the DIO-exercise&standard diet and the control group (P>0.05).Conclusions 1. The rat model of IR was successfully established by feeding the SD rats 8 weeks with high fat diet. After feeding high fat diet for another 8 weeks, the lipid deposition, lipid peroxidation in skeletal muscle and IR were even more serious.2. The aerobic exercise and/or standard diet treament can improve IR and the abnormal lipid metabolism of skeletal muscle. The reduction of lipid deposition and enhancement of capacity of lipid oxidation in Skeletal muscle may be one of mechanisms on aerobic exercise improving insulin resistance.