Objective To compare the protective effect of insulin-like growth factor-1(IGF-1) and ischemic postconditioning on ischemia-reperfusion myocardium apoptosis,and explore the possible mechanisms of inhibition of apoptosis of myocardial cells.Methods Forty eight SD rats were randomly divided into 4 groups(12 each): sham-operation group(sham),ischemic/reperfusion group(I/R),ischemic postconditioning group(I-POST) and IGF-1 postconditioning group(IGF-1-POST).The rat model was established by repeated ligation.Except the sham group,rats in the other three groups subjected to 45min of ischemia followed by 120min of reperfusion.During the first 30min of the reperfusion period,the cardiac electrical activity was recorded.In the 120th minute of the reperfusion,the hemodynamic parameters were monitored.The serous TNF-α,IL-6 and IL-10 levels were detected by ELISA.The degree of myocardial damage was observed by HE staining.Apoptosis was detected by TUNEL,and the expressions of Pser-133-CREB and Bcl-2 protein were monitored by Western blotting and immunohistochemical methods.Results Compared with that in I/R group,the cardiac function of rats in I-POST group and IGF-1-POST group was improved;the serous TNF-α and IL-6 levels were lower while IL-10 level was higher;the elevation degree of ST segment,the ventricular premature beats and the duration of ventricular arrhythmia decreased at the same time;the degree of myocardial damage lessened and the number of apoptosis cells increased;the expressions of Pser-133-CREB and Bcl-2 protein increased significantly(P < 0.05).In comparison with the I-POST group,TNF-α decreased but IL-10 increased significantly in IGF-1-POST group(P < 0.05);the elevation degree of ST segment,the ventricular premature beats and the duration of ventricular arrhythmia increased significantly(P < 0.05).As the other aspects mentioned above,no statistical difference was found between the two groups(P > 0.05).Conclusions IGF-1 may play a protective effect on ischemia-reperfusion myocardium in a similar extent to that of ischemic postconditioning.The anti-apoptosis effect of IGF-1 and ischemic postconditioning may be related with the high expressions of Pser-133-CREB and t Bcl-2 protein.
