Collaborative Work to Evaluate Toxicity on Male Reproductive Organs by Repeated Dose Studies in Rats

Nitrofurazone (NF) has been previously demonstrated to induce testicular toxicity with 4 weeks of oral administration in rats, ln the present study, rats were administered NF to assess whether testicular toxicity becomes evident with a 2-week administration period, Male Sprague-Dawley rats were administered oral doses of NF at 50 mgfkg fbr 2 or 4 weeks. Another group was administered NF at 100 mgfkg for 2 weeks, The control animals received the vehicle (O.5% methylceLlulose) fbr 4 weeks. Organ weights of the testis and epididymis were significantly decreased in all NF-administered animals, and seminiferous tubules were severely atrophied, due to a total absence of spermatids and degeneration a d desquamation of spermatocytes, In the epididymis, decreased numbers of sperrnatozoa were evident in the ducts, In rats that were administered NF at 50 mglkg, the changes in the epididymis in the 2-week group were less prominent than those in the 4-week group, In the testis, however, the changes were similar in both groups. Thus it was demonstrated that NF-induced testicular toxicity comparable to that observed after 4 weeks of administration is also detectable after 2 weeks,