Effects of malathion on cellularity and sperm differentiation in testis and epididymis of adult rats

Malathion is an organophosphorous insecticide, used worldwide for pest and disease control; however, it could also affect the reproductive patterns of several species. The aim of this study was to determine the effects of malathion in the cellularity and sperm differentiation in testis and epididymis of rats. Twenty adult male Sprague Dawley rats were divided into a malathion-treated group (n=10, dose of 170 mg/kg via subcutaneous injection for a period of 13 days) and control group (n=10, injected only with normal saline). After treatments, the rats were sacrificed by regulated euthanasia and assessed for sperm count in testis and epididymis and epididymal teratospermia degree. The results showed a significant decrease in body, testicular and epididymal weight in animals treated with malathion. Testicular sperm counts in treated rats exhibited a significant decrease in the number of sperm compared to controls (42.56×10⁶ vs. 95.99×10⁶), as well as in epididymis (77.55×10⁶ vs. 106.54×10⁶). Concerning the degree of teratospermia, a significant increase of abnormal sperm in the epididymis of treated rats versus controls (42.1% vs. 21%, respectively) was observed. We conclude that malathion has a cytotoxic effect in rats, significantly reducing the number of sperm produced by the seminiferous tubules and affecting their quality and number during the process of maturation and capacitation in their transit through the epididymis, thus increasing the level of teratospermia.