Toluene inhalation induced epididymal sperm dysfunction in rats

Toluene is a widely abused inhaled solvent. This study was designed to dete rmine whether toluene abuse affects the reproductive functions or general h ealth of males. Seven-week-old male Sprague-Dawley rats were exposed to tol uene vapor inhalation (0, 4000, or 6000 ppm; 2 h/day) daily for 5 weeks. Ex posure-related suppression of body weight gain and food consumption were ob served. Salivation and lacrimation were observed during exposure periods an d intensified with repeated exposure. Rats exposed to 6000 ppm toluene had decreased spleen and thymus weights, as well as suppressed lymphocyte count s. In 6000 ppm group, the epididymal sperm counts, sperm motility, sperm qu ality and in vitro penetrating ability to zona-free hamster eggs were signi ficantly reduced, while no exposure-related changes in the testes weight or spermatogenesis within testes were detected. Tail-less sperm heads were se en within zona-free eggs incubated with sperm from rats exposed to 6000 ppm toluene, but not control rats. No significant changes were observed in ser um luteinizing hormone, follicle-stimulating hormone, or testosterone level s following 1 month of exposure to 6000 ppm toluene. These results indicate that high concentrations of toluene may directly target sperm in the epidi dymis and disrupt sperm maturation. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.