The Role Of Apelin In Ischemia Reperfusion Injury In Myocardium In Experimental Animals

Myocardial ischemia and subsequent reperfusion lead to formation of a number of intrinsic factors which mediate the cellular mechanisms of adaptation to altered oxygen and energy supply, One of them is adipocytokine apelin, which is firstly isolated from bovine stomach extracts and identified as the endogenous ligand of the human orphan G protein-coupled receptor APJ.Aim: Study the effect of apelin on ischemia/reperfusion injury and try to clarify the possible mechanisms of this effect.Material & Methods: The present work had been carried out on 58 adult male albino rats. The animals were divided into four main groups where the effects of apelin was studied.Results: The results of this study showed that LDH and CK-MB levels were not significantly decreased with respect to the control when apelin-13 was given before ischemia (Ap-pre C), but, they were significantly decreased when apelin-13 was infused after ischemia (Ap-post C).In addition it was found that MDA level was also significantly decreased when apelin-13 was administrated after ischemia not before it besides it was found that infarction size was significantly decreased when apelin-13 was also administrated after ischemia.Moreover in presence of L-NAME and apelin-13 post ischemic, the previous protective effects of apelin-13 were abolished and LDH , CK-MB ,MDA levels and infarction size were not significantly different from the control groupConclusion: The cardioprotective effects of apelin mimic ischemic postconditioning, but not preconditioning interventions; it could reduce the markers of tissue damage and decrease the infarction size when it was applied at the beginning of reperfusion. In addition The present study revealed abolishment of the cardioprotective effect of apelin in the presence of L-NAME, а nonspecific NOS inhibitor. These findings indicate involvement of NOS-dependent mechanisms in apelin-induced attenuation of myocardial I/R injury..