Abstract: The objective of this study was to explore the protective effect and the mechanism of oleuropein and diltiazem on myocardial ischemia-reperfusion injury in rats.Fifty health rats were divided into five groups,namely sham group,model group,oleuropein group,diltiazem group,oleuropein and diltiazem group.The model was established by the ligation of descending coronary artery in rats.After modeling,the rats were administrated with oleuropein,diltiazem,and oleuropein+diltiazem for 7 d.The contents of tumor necrosis factor-α (TNF-α),interleukin-1β (IL-1β) and interleukin-10 (IL-10) were detected by radioimmunoassay.The activities of superoxide dismutase (SOD) and catalase (CAT) as well as the content of malondialdehyde (MDA) were measured by spectrophotometry.The changes of myocardial ednothelin-1 (ET-1) expression in myocardium were analyzed by Western blot assay.The results showed that compared to sham group,the contents of TNF-α,IL-1β and MDA were significantly increased,the levels of IL-10,SOD and CAT were significantly reduced,the myocardial ET-1 expression was significantly up-regulated in myocardium of model group mice (P<0.01).Compared to model group with the treatments of oleuropein,diltiazem,and oleuropein+ diltiazem,the contents of TNF-α,IL-1β and MDA were significantly decreased,the levels of IL-10,SOD and CAT were significantly increased,the myocardial ET-1 expression was significantly down-regulated in myocardium of treatment group (P<0.05, P<0.01).Furthermore,the oleuropein+ diltiazem combined administration showed an even more significant positive effect.Based on these results,it was concluded that the treatments of oleuropein and diltiazem had a protective effect on myocardial ischemia-reperfusion injury,the mechanisms of which may depend on reducing myocardial ET-1 expression,improving antioxidant enzyme activity and inhibiting inflammatory response.

Key words: oleuropein, myocardial ischemia-reperfusion injury, diltiazem, inflammatory factors, antioxidant capacity, ET-1