Study of the injurious effects of neutrophils on myocardium and their medicinal therapy in rabbits / 第三军医大学学报

ABSTRACT

It was found that there was a significant increase of the number of circulating leucocytes 2h after a subcutaneous injcetion of isoprenaline and severe myocardial necrosis occurred after consecutive injections for 3 d.Cytoxan-induced depletion of leucocytes resulted in an obvious decrease of the percentage of myocardial necrosis.In the control.the neutrophilic phagocytosis was enhanced and their release of acid phosphatase elevated greatly,which indicates that the neutrophils are in an activated state.After the.neutrophils were inhibited with dexamethasone or indomethacint significant reduction of the contents of prostaglandin E2 and malondialdehyde and an increase of superoxide dismutase activty in the myocardium were observed and consequently myocardial necrosis was greatly alleviated.Our findings suggest that neutrophils might play an important role in the pathogenesis of myocardial infarction through the release of lysosomal enzymes and the production of oxygen-derived free radicals and certain metabolites of arachidonic acid,and proper regulation of the neutrophilic functions could exert prophylactic effects on myocardial infarction.This might be a promising direction to look for more effective drugs to treat myocardial infarction.