Effects of N,N'-methylene-bis-acrylamide (MBA) on mouse germ cells--sperm count and morphology, and testicular pathology.

The sperm count and morphology, and testicular histopathology were studied in mice over a period of 75 days following a single oral administration of 50, 100, and 200 mg/kg N.N'-methylene-bis-acrylamide (MBA). With a 50 and 100 mg/kg dose, the sperm abnormality reached a maximum at 30 days, whereas the sperm count reached a minimum at 35 days. The abnormality and decrease in sperm count were both dose dependent. Following the administration of 200 mg/kg MBA, the appearance of abnormal sperm showed a diphase pattern, i.e., first at 7-15 days without any reduction of the sperm count and second at 30 days after treatment. Testicular histopathological changes showed that resting spermatocytes, succeeding leptotene and zygotene spermatocytes were either absent or reduced 1-3 days after treatment with 200 mg/kg MBA. These early histopathological changes seemed to precede both the increase in abnormal sperm and the decrease in sperm count observed 30-35 days post-treatment, and also suggested that resting spermatocytes were most sensitive to MBA exposure among various spermatogenic cells.