| AIM Myocardial ischemia reperfusion injury has a close correlation with myocardial apoptosis. Insulin is a hormone that contains 51 amino acid and is synthesized by B cell in pancreas. In recent years, because some cardiovasular syndromes often occur on diabetic patients, the effects of insulin on cardiovasular system drew researchers' attention. Glucose-insulin-potassium solution (GIK cocktail) had been used on the clinic treatment to acute ischemia reperfusion injury for forty years, but the mechanisms of the effect keep unknown. The aims of this study were to observe the protective effects of GIK solution on rabbits acute ischemia/reperfusion heart, try to investigate its potential mechanisms and .determine the protective effects of insulin in GIK solution. To study the effection of GIK on the myocardial protection in MI/R mainly through anti-apoptotic effect by insuline or not. Comparative study of the effects of high dose glucose-insulin-potassium (GIK) and low dose glucose-insulin-potassium cocktail on cardiac myocyte apoptosis and cardiac functional recovery following myocardial ischemia/reperfusion (MI/R). GIK is effective on the myocardialprotection in MI/R mainly through anti-apoptotic effect, and there was significant difference between the high dose GIK and the low dose GIK.Methods Myocardial ischemia reperfusion model in rabbits were made and were divided into five groups randomly. Rabbits were subjected to 45 min of regional myocardial ischemia and 3 h of reperfusion Anesthetized rabbits were randomly treated with continuous infusion of saline ,LGIK (Glucose 100g/L,Insulin 20u/L and KC1 20 mmol/L) ,HGIK (Glucose 300g/L, Insulin 50U/L and KC1 80 mmol/L), GK(Glucose 100g/L,and KC1 20 mmol/L) insulin (50 U/L) at 1.5 ml-1 kg h-1 ,beginning 5 min before reperfusion and continuing through the 3 h reperfusion. Arterial blood pressure, ECG and left ventricular pressure were monitored throughout the experiment. The index of myocardial function was recorded and analyzed. The animals were sacrificed and the heart was harvested. Infarced sizes in heart were deterimined by dual staining with Evans-blue and TTC. Apoptosis was identified by TUNEL and apoptosis index (AI)was obtained .The expression of Fas,Bcl-2 protein was measured by immunohistochemical technique. The activities of CPK,MDA, and SOD and FFA, ATP were determined at the end of reperfusion.Results MI/R caused significant cardiac dysfunction and myocardial death (both necrosis and strong apoptosis ). Our experimental results are follows:1.Compared with the vehicle treated rabbits, the HGIK-treated rabbits and the LGIK-treated rabbits and insuline group showed protection against MI/R injury as evidenced by reduced Lvedp(P<0.05),and increased the +dp/dtmaX(P<0.05). There wassignificant difference between the high dose GIK and the low dose GIK(P<0.05)and there was not significant difference between the high dose GIK and the insuline(P>0.05). The protection of the high dose GIK higher than the low dose GIK.2.The results show that all indexes related to injure, namely CPK, and the ratio of myocardial ischemic and necrotic area, show injure attenuation in HGIK-treated rabbits and the LGIK-treated rabbits and insulin-treated groups in comparison with control group (P<0.05). The significant difference between the high dose GIK and the low dose GIK were intendfied(P<0.05)and there was not significant difference between the high dose GIK and the insuline(P>0.05). The protection of the high dose GIK higher than the low dose GIK. .3.Compared with the vehicle treated rabbits, the HGIK-treated rabbits and the LGIK-treated rabbits and insuline group showed protection against MI/R injury as evidenced by reduced FFA,and increased the ATP(P<0.05). There was significant difference between the high dose GIK and the low dose GIK(P<0.05)and there was not significant difference between the high dose GIK and the insuline(P>0.05). The protection of the high dose GIK higher than the low dose GIK.4. The results show that all indexes related to injure, name... |
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