The antiviral drug ribavirin reversibly affects the reproductive parameters in the male Wistar rat.

The present study was planned to evaluate the toxic effects of ribavirin on the reproductive parameters in the male Wistar rat. Rats (11--13 weeks old) were treated with 5 injections (i.p.) of 20, 100 or 200 mg/kg/day ribavirin at intervals of 24 h. The testes were processed for histopathological analysis on days 14, 35, 70 and 105 after the last exposure. The parameters studied were body weight, the weights of the testis, epididymis, seminal vesicle and prostate, seminiferous tubular diameter (STD), epithelial height (SE), epithelial sloughing, incidence of stage XIV tubules, sperm abnormality and total serum level of testosterone. Data were analysed by ANOVA and the Bonferroni post hoc test for significances between different groups. There was a decrease in body weight and organ weights, excluding those of the testis and epididymis, against control at higher dose-levels. Ribavirin induced the formation of vacuoles, gaps and sloughing of the seminiferous epithelium. The STD, SE and the incidences of stage XIV tubules decreased on days 14 and 35. Ribavirin also induced the formation of sperm with microcephaly and cephalocaudal junction defects, with or without fibrils jetting out. All these morphological defects recovered to control limit by day 105. The serum level of testosterone was decreased at all dose-levels and time points, although recovery had started by day 105. In conclusion, ribavirin is gonadotoxic in male rats but the effects are reversible after a period of 105 days. However, the endocrine-disrupting properties of ribavirin persist beyond this period.