The Role of Bradykinin in Myocardial Ischemic Preconditioning

Objective The aim of the present study was to determine whether bradykinin has a protective effect during ischemia?reperfusion and involves in ischemic preconditioning in the rat heart.Methods Acute reversible left main coronary artery occlusion was used.Forty healthy SD rats were randomly divided into five groups:(1)ischemia?reperfusion(IR); (2)ischemic preconditioning (IP); (3)treatment with bradykinin before ischemia( BK+IR); (4) bradykinin treatment combined with pretreatment with bradykinin B 2 receptor antagonist B 1650 before ischemia (BK+BKA+IR); (5)ischemic preconditioning combined with B 2 receptor antagonist B 1650 (BKA+IP). Heart function before and after ischemia?reperfusion were examined.We also measured the content of malondialdehyde(MDA) and superoxide dismutase(SOD) at the end of reperfusion.Results Bradykinin reduced the injury induced by ischemia?reperfusion,improved the heart function,decreased the MDA production,increased the SOD activity.Pretreatment with bradykinin B 2 receptor antagonist B 1650 completely abolished the effect of bradykinin or ischemic preconditioning.Conclusion Bradykinin, through B 2 receptors,can protect ischemic myocardium from ischemic injury , and is involved in ischemic preconditioning in our model.