Study On Pathological Observation And Apoptotic Mechanism Of Myocardial Ischemia-reperfusion Injury Of Rat

Objective: To investigate isolated rat myocardial ischemia-reperfusion: 1 .the pathological change of organism structure, 2 , the incidence of cardiomyocyte apoptosis,3.the expression in apoptosis-associated factors of TNF -α, Bcl-2/Bax.Methods: Preparation of isolated rat heart ischemia-reperfusion model uses Lengendorff Isolated Heart Perfusion System. 40 Sprague-Dawley rats are randomly divided into four groups : control group (continuous perfusion group, 1st group), 30 min ischemia-reperfusion group (2nd group), 60 min ischemia-reperfusion group (3rd group), Ischemic-preconditioning group(4th group); perfuse heart with K-H liquid of 4℃, 80cm the water column, under condition of constant pressure and temperature, at the end of the experiment ,cardiac apex fixed paraffin-embedded tissue sections are performed apoptosis by TUNEL and immunohistochemical method are detected T NF-α, Bcl-2, Bax; Another group trip Ultrathin sections observed.Results: 1. Pathological injury after Myocardial Ischemia-reperfusion Obviously, Visibility electron microscope observation of apoptotic bodies confirmed the formation of ischemia-reperfusion myocardial apoptosis, 60 min ischemia -reperfusion group has highest rate of apoptosis (18.14%±7.69); the rate of apoptosis of 120 min ischemia-reperfusion group (15.59%±6.31) has not increased but for a number of necrosis; Ischemic-preconditioning can reduce myocardial injury and the rate of apoptosis. 2. the expression of TNF in Myocardial Ischemia-reperfusion injury significantly increased; the expression of Bcl-2 performs weakening with the extension of the ischemic time, Bax will strengthen, the ratio of Bcl-2/Bax performs dropping. Preconditioning group expressed TNF-αsignificantly weaker than ischemia-reperfusion group, Bcl-2/Bax ratio is also higher than the ischemia-reperfusion group.Conclusions: Pathological injury after Myocardial Ischemia-reperfusion is Obviouse,with the performance of apoptosis and 60 min ischemia-reperfusion group has highest incidence of apoptosis; the rate of apoptosis of longer time of ischemia-reperfusion group has not increased but for a number of necrosis; TNF-α, Bcl-2, Bax and other related apoptosis factors in the occurrence of myocardial apoptosis is obvious expression; preconditioning reduces ratio of myocardial apoptosis through going down TNF-αand raising Bcl-2/Bax.