Anabolic-androgenic steroid-induced toxicity in primary neonatal rat myocardial cell cultures

Recent literature reports of myocardial infarction in athletes who self-administer anabolic-androgenic steroid (AAS) and previous animal studies of the effects of AASs on the heart suggest that these drugs may be directly injurious to the myocardium. We have previously demonstrated that 100 microM testosterone cypionate (TC) inhibits all beating activity of primary neonatal rat myocardial cell cultures within 1 hr of exposure and causes significant LDH release by 4 hr of exposure, indicating a direct toxic effect of TC. The purpose of this investigation was to evaluate the effects of commonly abused AASs on primary neonatal rat myocardial cell cultures and to provide insight into early cellular changes that may lead to TC-induced toxicity. Significant LDH release was observed in 5-day-old primary myocardial cell cultures (obtained from 3-to-5-day-old Sprague-Dawley rats) exposed to 100 microM testosterone enanthate (TE), testosterone propionate (TP), and oxymetholone (O) for 4 and 24 hr and in cultures exposed to 100 microM testosterone (T) for 24 hr. Neutral red retention and MTT formazan production were significantly decreased in cell cultures exposed to 100 microM TE, TP, and O after only 4 hr of exposure, indicating a loss of viability and mitochondrial activity. However, there was no effect on viability of cell cultures exposed for 24 hr to 100 microM of a variety of other commonly abused AASs. Phase-contrast microscopy revealed complete disruption of the monolayer in cell cultures treated with 100 microM TE, TP, and O for 4 hr. Treatment of fura-2-loaded myocardial cell cultures with 100 microM TC produced no significant changes in calcium transients or baseline calcium levels for up to 13 min of exposure. These results indicate that O, T, TC, TE, and TP produce a direct toxic effect in heart cell cultures and that early (< 13 min) changes in calcium homeostasis are unlikely to participate in the mechanism of toxicity.