The Effects of Cocaine Injections on Mouse Thymocyte Population

AbstractC57 BL mice were injected daily with either saline or varied doses of cocaine (5–50 mg/kg), and thymocyte subpopulations were analyzed 4 hr after the fifth injection. Mice injected with either 25 or 50 mg/kg of cocaine showed a decrease in the percentage of CD4+8+ cells and increase of CD4−8−, CD4+, and CD8+ cells. The absolute numbers of each subpopulation, calculated by multiplying the percentage of each subpopulation with the total cell number, revealed an extensive decline in CD4+8+, a decrease in CD8+, an increase in CD4−8−, and no change in the CD4+ subpopulation. Flow cytometric analysis of thymocytes and electrophoresis of the thymocyte DNA revealed a dosage-dependent increase in cells undergoing programed cell death with apoptosis. Culturing of thymocytes from control or drug-treated mice demonstrated an inverse relationship between cell viability and cocaine concentrations, suggesting that in vivo cocaine, or its biological products, may damage thymocytes. Incubation of normal cells with...