Acute Effects and Long‐Term Sequelae of 1,3‐Dinitrobenzene on Male Reproduction in the Rat I. Sperm Quality, Quantity, and Fertilizing Ability

Groups of eight adult male rats were given a single oral dose of 0 or 48 mg/kg of 1,3‐dinitrobenzene and sacrificed at 1, 2, 4, 8, 16, 24, 32, 72, and 175 days posttreatment. The groups killed at 175 days were bred to untreated females during weeks 3, 4, 6, 9, 13, and 24. Decreased testis weight and testicular sperm numbers were observed by day 4; decreased cauda sperm reserves and epididymis weight occurred by day 8 and day 16, respectively. Reduced numbers of motile spermatozoa and abnormal sperm morphology were seen in spermatozoa from the cauda epididymidis by day 16. Fertilizing ability, as indicated by the presence of two pronuclei and a sperm tail in eggs flushed from the oviducts of inseminated females, was slightly reduced by week 4 and declined to zero by week 6. Group means for reproductive organ weights, sperm production, and sperm reserves failed to return to control levels although some individual animals approached full recovery. Normal fertilizing ability was restored in most animals by week 13, but two of seven remained infertile. Occlusion of some efferent ductules was observed in three of seven animals at 175 days. This study indicates that 1,3‐dinitrobenzene is a potent testicular toxicant in the rat, capable of producing marked testicular damage, infertility, and possibly sterility from a single exposure. 1988 American Society of Andrology