| With the development of social economy and improvement of people’s livingstandard, the incidence rate of various modern diseases, such as type2diabetes,coronary heart disease, fatty liver, high blood pressure, hyperglycemia, have risenincreasingly, which are caused by obesity and insulin resistance. And many recentstudies showed that insulin resistance which was caused by obesity was closely relatedto HSP72(Heat Shock Protein72). As a result, to improve insulin resistance, drugs andheat treatment would increase HSP72expression. However, a great number of studiesshowed that insulin resistance could be improved by exercise, its mechanism hasn’tbeen clearly stated. The question is whether insulin resistance improved by exercise willinfluence HSP72expression.Purpose：The study was designed to have long-term swimming exercise trainingand one swimming exercise training respectively to explore the effect on insulinsensitivity of insulin resistance rats by the high fat diet. Also, to explore the role ofHSP72and JNK proteins in skeletal muscle changes.Methods：Expeirment one:The study objects26Sprague-Dawley pure male rats wererandomly divided into four groups, Control Group (C), High Fat Group (H), High Fatand Exercise Group (HE) and Exercise group (E). For Group C, ordinary diet withoutswimming. For Group H, high fat diet without swimming. For Group HE, high fat dietwith swimming and for Group E, ordinary feed with swimming. At the end of12weeks,the study was to observe each group’s changes of body weight, visceral fat weight,glucose and insulin. Besides, it was to observe the differences of HSP72and JNKexpression in/of skeletal muscle.Expeirment two: The study objects46SD pure male rats were randomly dividedinto two groups, high fat diet and ordinary diet. At the end of12weeks,the two groupswere arranged to have90min swimming. After that, they were sacrificed beforeswimming, immediately after swimming,60min after swimming and180min after swimming respectively. They were divided into eight groups, Control GroupCC(ordinary diet), Group CE0(immediately after swimming), Group CE60(60minafter swimming) and Group CE180(180min after swimming) Control Group CH(highfat diet), Group HE0(immediately after swimming), Group HE60(60min afterswimming) and Group HE180(180min after swimming).Results：1. General IndexExpeirment one:There was no significant difference of rats’ weight among fourgroups. After12weeks, rats’ weight in Group H was obviously higher than that inGroup C（P<0.05）and Group HE（P<0.01）. Rats’ visceral fat weight in Group H wasobviously higher than that in Group C（P<0.01）and Group HE（P<0.05）, and rats’visceral fat weight in Group E was obviously lower than that in Group C P<0.05）.Amount of rats’ average daily input in Group H was obviously higher than that in GroupC（P<0.01）and Group HE（P<0.01）and amount of rats’ average daily input in GroupE was obviously lower than that in Group C（P<0.05）.Expeirment two:There was no significant difference of rats’ weight at the beginning（P>0.05）.After12weeks, body weight, visceral fat, fat body weight ratio in Group CHwere obviously higher than that in Group CC (P<0.01，P<0.05，P<0.01）.2. Serum IndexExpeirment one:After12weeks, blood glucose concentration of Group E wasobviously lower than that in Group C. Insulin concentrations of Group H was obviouslyhigher than that in Group C（P<0.01）and Group HE（P<0.01）. Insulin sensitivity indexin Group E was obviously higher than that in Group C（P<0.01）and insulin sensitivityindex in Group H was obviously higher than that in Group HE（P<0.01）. Insulinresistance index in Group H was obviously higher than that in Group C（P<0.01）andGroup HE（P<0.05）and insulin resistance index in Group E was obviously lower thanthat in Group C（P<0.01）. FFA in Group H was obviously higher than that in Group C（P<0.01）and FFAin Group HE was obviously lower than that in Group H（P<0.01）.Expeirment two:Compared with Group CC, blood glucose concentration of GroupCE0, Group CE60and Group CE180were decreased by6%,12%and13%, but there was no statistical significance among groups（P>0.05）. Insulin concentrations of Group CE0,Group CE60and Group CE180were decreased by5%,15%and12%. Insulin sensitivityindex in Group CE0, Group CE60and Group CE180were increased by2%,5%and3%.The indexes were obviously decreased in Group CE60（P<0.05）.Compared with Group CH, blood glucose concentration of Group HE0, Group HE60and Group HE180were decreased by2%,12%and22%, and there was significantdifference in Group HE180（P<0.05）. Insulin concentrations of Group HE0, Group HE60and Group HE180were decreased by7%,16%and29%, and there was significantdifference in Group HE180（P<0.05）. Insulin sensitivity index in Group HE0, GroupHE60and Group HE180were increased by2%,6%and13%and there was no significantdifference between Group HE60and Group HE180（P<0.05å'ŒP<0.01）. And there wasno statistical significance among other groups.3. HSP72and JNK protein exerpressionExpeirment one: After12weeks, HSP72in rats’ gastronomies muscle in Group Hwas obviously lower than that in Group C, but JNK in Group H was obviously higherthan that in Group C（P<0.05）. HSP72in Group HE was obviously higher than that inGroup H, but JNK in Group HE was obviously higher than that in Group H（P<0.01）.HSP72and JNK in Group E were obviously higher than that in Group C（P<0.05）. Andthere was no statistical significance among other groups.Expeirment two:As for HSP72, Group CH was obviously lower than that in GroupCC（P<0.05）.Compared with Group CC, HSP72in Group CE0, Group CE60and GroupCE180were increased by7%,17%and26%. And compared with Group CE60andGroup CE180, there were significant differences（P<0.05å'ŒP<0.01）；Compared withGroup CH, HSP72in Group HE0, Group HE60and Group HE180were increased by13%,26%and34%. And there were significant differences between Group HE60andGroup HE180（P<0.05å'ŒP<0.01）. And there was no statistical significance amongother groups. Conclusion:1. Insulin resistance in rats can be caused by12-week high fat diet. Swimmingexercise and an acute swimming exercise can also improve it to some extent.2. Insulin resistance caused by high fat diet is related to low HSP72in skeletalmuscle which diminished the inhibition on JNK. Besides, HSP72and inhibition on JNKprotein can be increased by exercise.3. Increase HSP72protein in resting skeletal muscle by exercise has relation withaccumulation of the results of each exercise.4. The way of HSP72-JNK may be one of the mechanisms on insulin resistance byexercise improvement. |
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