Abstract: Objective To investigate the reproductive system impairment induced by cocaine in adult male rats and the possible underlying mechanism. Methods Thirty adult male rats were randomly divided into experimental and control groups, with 15 rats in each group. Rats of the experimental group were injected cocaine hydrochloride(15 mg/kg body weight) subcutaneously daily for four weeks. The weight of body and testis, as well as the level of serum hormone of the rats were examined. In addition, the apoptosis rate of testicular tissue by TUNEL and the expression of Fas gene in testicular tissue were examined by immunohistochemistry. Results Compared with the control, the weight of testis in the cocaine exposed group decreased significantly (P<0.05), and the serum testosterone level decreased significantly(P<0.05). Moreover, both the apoptosis rate and the expression of Fas gene increased in the testicular tissue of rats in the cocaine exposed group in comparison to the control group(P<0.05). The apoptosis rate was significantly correlated with the expression of Fas gene(r=0.9012, P<0.05). Conclusion Cocaine may cause reproductive system injury in adult male rats, and Fas-mediated apoptosis may be one of the functional mechanisms involved in the reproductive system injuried by cocaine.

Key words: forensic toxicology, cocaine, reproductive function, apoptosis, rat