원광대학교 의과대학 소아과학교실 해부학교실 * 내과학교실 ** 윤향석·박승택 * ·박옥규 ** Background:In order to elucidate toxic mechanism of the oxygen radicals on cultured rat myocardial cells, cytotoxic effect of oxygen radicals was evaluated by MTT assay. In addition pr- otective effect of glutathione(GSH on oxidant-induced cardiotoxicity was investigated on these cultures. Methods:Myocardial cells derived from neonatal rats were cultured for 12 hours in the medium containing various concentrations of glucose oxidase(GO. Cell viability was measured by MTT assay and morphological changes of the myocardial cells were observed by light microscope. Results:GO-mediated oxygen radicals remarkably decreased cell viability of cultured myocar- dial cells in a dose-and time-dependent manner. And also, GSH blocked GO-induced cardiotoxicity in these cultures. Conclusion:These results suggest that the oxygen radicals are toxic and the selective anti-oxidants such as GSH are effective in blocking against the oxidant-induced cardiotoxicity in cultures of the myocardial cells of neonatal rats.