FREE-RADICAL DAMAGE IN NEONATAL RAT CARDIAC MYOCYTE CULTURES - EFFECTS OF ALPHA-TOCOPHEROL, TROLOX, AND PHYTOL

A number of investigations have implicated free radicals in the progressive of ischemic/reperfusion injury. α-Tocopherol has been found to attenuate alterations due to ischemia and reperfusion in an isolated heart model. The present study was intended to directly examine neonatal rat cardiac ventricular cells cultures exposed to a free radical generating system catalyzed by xanthine oxidase. The effectiveness of α-tocopherol in the attenuation of the resulting changes and the mechanism by which by which the effects of α-tocopherol may be exerted were evaluated. Cultures were either nontreated or pretreated for 18 h with 20 μM α-tocopherol or the subcomponents of the α-tocopherol molecule, phytol and Trolox. Exposure of cell cultures to free radicals resulted in significant increases in lipid peroxidation products, release of both lactate dehydrogenase and 3H-arachidonate, and stuctural alterations. Pretreatment with α-tocopherol showed significant attenuation of the changes associated with exposure to free radicals. Trolox and phytol at equal molar doses were not as effectivene as α-tocopherol in protecting the myocytes against injury. Thus, α-tocopherol seems beneficial in its ability to reduce free radical-mediated changes by functioning as a lipophilic antioxidant. Additionally, the intact, native α-tocopherol molecule exceeded the protective capabilities of either of its subcomponents. © 1990.