Bromelain Protects The Myocardium Against Ischemia Reperfusion Injury In Rats

Objective: To investigate the protective effect of Bromelain on myocardial ischemia-reperfusion injury and the action mechanismMethods: Make the myocardial I-R model in Sprague-Dawley rats.Thirty-two rats were randomly divided into four groups(n=8):sham-operated group(A),PBS preconditioning group(B),Br+PBS preconditioning group(C), I-R group(D).A group underwent opening of the chest only without ligation of the LAD,without medicine preconditioning ;B group was administered with PBS via intraperitoneal injection for 15 consecutive days. On day 16, the LAD were ligated for 30 min ,followed by 2 h of reperfusion.C group was administered with PBS and Br via intraperitoneal injection for 15 consecutive days, residue is the same as B group.D group only ligate the LAD for 30 min ,followed by 2 h of reperfusion, without medicine preconditioning.Monitor the changes ST-stage by ECG lead II .The levels of CK-MB and LDH were measured 2 hours after reperfusion. Myocardial infaction(MI) size and risk size were determined by Evans blue and TTC staining .Myocardial cell apoptotic index was determined by Tunel .The change of phospho-AKT was determined by western blot.Results: Compared with B,Dgroup ,C group decrease the releasing of CK-MB and LDH,decrease MI side and apoptotic index,and increase the phosphorylation of AKT;B group and D group have no significant difference.Conclusions: Br preconditioning protects the myocardium against I-R injury by increasing the phosphorylation of AKT,so as to decrease apoptotic index and MI side,and decrease the releasing of CK-MB and LDH.