Cardiac disease induced by chronic adriamycin administration in dogs and an evaluation of vitamin E and selenium as cardioprotectants

Abstract

Chronic adriamycin (ADR) intoxication was produced in three groups of beagle dogs by weekly intravenous injections (1 mg/kg body weight) for 20 weeks (cumulative dose 400 mg/sq m). Group A (6 dogs) received ADR only; Group B (6 dogs) were given ADR and weekly doses of vitamin E (17 mg/kg body weight) as alpha-tocopherol acetate; and Group C (6 dogs) received ADR and weekly doses of vitamin E as did Group B and selenium (0.06 mg/kg body weight as selenite). Each of the 18 dogs developed ADR-induced cardiomyopathy (CMY), and death occurred in 11 dogs during Weeks 17-20. Mortality was lowest in Group B (2 of 6), but no differences between groups were seen either in survival time of the dogs that died or in severity of CMY. Cardiomyopathy was more severe in dogs that died than in survivors. Congestive heart failure with transudation was present in 4 of 11 dogs that died. Cardiac histopathology was characterized by vacuolar degeneration of myocytes. Myocardial damage was most severe in the left ventricle and the ventricular septum, intermediate in the right ventricle and the left atrium, and least in the right atrium. Ultrastructural study showed that an early alteration in damaged myocytes was distention of sarcoplasmic reticulum to form sarcoplasmic vacuoles. Occasional damaged fibers had myofibrillar lysis and focal proliferation of sarcoplasmic reticulum. This study demonstrates that the dog offers a suitable model for studies of chronic ADR cardiotoxicity in man. The lack of cardioprotection from vitamin E and selenium supplementation fails to support the proposed role of lipoperoxidative damage in the development of chronic ADR-induced CMY.