| Objective:To observe the expression ofadiponectin(APN),tumor necrosis factor-α(TNF-α) in blood samples and myocardial tissue of streptozotocin(STZ)-induced diabetic rats,and the changes of myocardium structure.Meanwhile,to explore the role of TNF-α,IGF-1 in the development of diabetic cardiomyopathy(DC)of STZ-induced diabetic rats.Methods:64 Wistar rats were divided randomly into two groups.There were 32 in STZ-induced diabetic group and 32 in normal control group.The subjects in diabetic group were injected intraperitoneally with STZ citrate buffer(STZ 50mg/kg),while the ones in normal control group were injected intraperitoneally with the similar dose of citrate buffer.After 1 week,4 weeks,8 weeks and 12 weeks,weight and fast Blood glucose were observed,serum APN,TNF-α,fast blood insulin were measured by ELISA and RIA,The changes of myocardium structure were observed by microscope and electronmicroscope,and the expression of myocardial tissue by immunohistochemistry Meanwhile,the changes of myocardium structure and immunohistochemistry were used to analyse morphologically.We analyze these data by SPSS software.Results:1.Compared with normal control group,myocardial cells swelling was observed by microscope and myofilament rarefaction,chondriosome swelling and escaping by electronmicroscope in diabetic groups.In normal control group,myofilament and chondriosome were tidy.pathohistological study revealed that there was thicker CBM(capillary basement membrane)ofmyocardium in 12 week diabetic rats than its in normal control group(P＜0.05).3.Except one week group,the serum level of APN in diabetic group was higher than its normal control group(1 week P＞0.05,others P＜0.01),and increased gradually.Meanwhile, the level of TNF-αin diabetic group was too higher than its normal control group(1 week P＜0.05,others P＜0.01),and increased gradually with the progression of DC.4.Compared with normal control group,the APN expression of myocardial tissue was strongly in diabetic group(1 week P＞0.05,others P＜0.01),and increased gradually(P＜0.01).Meanwhile,TNF-αwas too.Its average optical density in diabetic group was higher than its in normal control group(P＜0.01),and increased gradually with the progression of DC(P＜0.01).5.There was a significant positive correlation between APN and TNF-αin diabetic group (r=0.896,P＜0.01).Conclusion:1.The changes of myocardium structure were obviously in the model of STZ-induced diabetics rats,but they were not in normal control group.2.The blood level of APN in diabetic group was higher than its normal control group except when one week.Compared with normal control group,the APN expression of myocardial tissue was strongly in diabetic group,and increased gradually.According these we can conclude that APN may play a protective role.3.The expression of TNF-αin diabetic group was more than its normal control group,and increased gradually with the development of cardiomopath.So we can see that TNF-αmay play a progressive role in the pathogenesy of diabetic cardiomyopathy.4.There was a significant positive correlation between APN and TNF-αin development of T1DM and DC of streptozotocin(STZ)-induced diabetic rats.APN may play a protective role, and meanwhile TNF-αis harmful in the progression of DC.The decrease of APN and the increased of TNF-αin serum level and the expression in heart tissue may play an important role in the therapy of DC.
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