Vitamins C and E protect isolated cardiomyocytes against oxidative damage

There is considerable evidence that oxygen free radicals are involved in re perfusion injury of ischemic myocardium. Epidemiologic studies showed an in verse correlation between plasma levels of alpha -tocopherol (vitamin E) an d ascorbic acid (vitamin C) and mortality from ischemic heart disease. The present study examines the influence of both vitamins on the toxic effects of singlet oxygen on isolated rat cardiomyocytes. Freshly isolated cardiomy ocytes from adult rats were exposed to singlet oxygen which was generated b y photoactivation of the photosensitive dye rose bengal (10(-7) M). This pr ocedure induced irreversible hypercontracture in about 95% of rod-shaped ca rdiomyocytes within 15 min after onset of photoactivation of rose bengal. P retreatment with vitamin C (10(-5) to 10(-2) M) or E (10(-6) to 10(-3) M) r educed the number of hypercontracted cells after exposure to singlet oxygen in a concentration-dependent manner. Simultaneous application of both vita mins (vitamin E 10(-6) M plus vitamin C 10(-5) M or vitamin E 10(-5) M plus vitamin C 10(-4) M) revealed a marked overadditive protective effect again st oxidative damage as compared with the single application of each vitamin . Our data show that alpha -tocopherol and ascorbic acid exert direct prote ctive actions on isolated cardiomyocytes against oxidative damage and provi de an overadditive effect if administered simultaneously. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.