Study on The Reproductive Organs and Fertility of The Male Mice following Administration of Metronidazole

Background: Metronidazole (MTZ) is commonly used as an antibacterial and antipro- tozoal drug. Various doses of MTZ have been reported to inhibit spermatogenic activity and sperm indices. Materials and Methods: In this experimental study, dose-dependent effects of MTZ on the structural and functional integrity of the testis and accessory reproductive organs have been investigated. Adult male mice of Swiss strain were administered orally with MTZ at the doses of 250 mg/kgBW/day and 500 mg/kgBW/day for 28 consecutive days to study the changes in the testis, epididymis, seminal vesicle, sperm indices and fertility. Reversal effects of the drug were also studied on the same mice, 42 days after cessation of the treatment. Results: Therapeutic dose of MTZ (250 mg/kgBW/day) neither altered the weights of the testis, epididymis and seminal vesicle nor their histoarchitecture and sperm indi- ces. The drug at the high dose (500 mg/kg BW/day) caused significant reductions in the weights of the testis and epididymis. Histoarchitecture of the testis and epididymis at the high dose revealed marked regressive changes while that of seminal vesicle remained unaffected. Significant reductions were noticed in the motility, viability and count of epididymal spermatozoa while the concentrations of epididymal sialic acid and seminal vesicular fructose remained unaltered after the treatment. No significant changes were noticed in the mating ability as well as in the level of serum testosterone in the treated mice. Fertility of the male mice treated with high dose of MTZ declined markedly lead- ing to an increase in pre- and postimplantation loss while a significant decrease was noticed in the number of live blastocysts in females impregnated with such males. MTZ- induced changes in the male reproductive organs and fertility were reinstated 42 days after cessation of the treatment. Conclusion: High dose of MTZ induced reversible deleterious effects on the male repro- duction and fertility.