Continuous Exposure of Lactating Rat Mothers to Polychlorinated Biphenyls (PCBs) Increases Testis Volume, Sperm Production and Sertoli Cell Numbers in Adult Male Offspring

Kim, In Shik; Yang, Hong Hyun; Cui, Cheng Du

Abstract

Despite the possible consequences of maternal ingestion of polychlorinated biphenyls (PCBs) on future generation, information in limited on how/whether maternal PCB exposure affects testis of the adult male offspring. Therefore, we conducted two experiments to investigate the effects of intermittent and continuous of lactating rats to low and high doses of Aroclor 1242 (a PCB congener) on volume density of seminiferous tubules and interstitium, testis volume, sperm production/day and the total number of Sertoli cells per testis in adult male offspring. In experiment I, 3 groups of lactating Sprague Dawley rats received daily subcutaneous injections of 0.1 ml of corn oil, low dose (8microgram) and high dose (80microgram) of Aroclor 1242 in corn oil respectively, from parturition to weaning of pups at 21 days. In experiment II, 3 groups of lactating rats received 2 subcutaneous injections per week of 0.1 ml corn oil, low and high doses of Aroclor respectively, as in experiment I. Pups in all groups were weaned at day 21 and were raised on a normal diet until sacrificed at 90 days to evaluate volume density of seminiferous tubules and interstitium, testis volume, sperm production/day and the total number of Sertoli cells per testis. Volume density of seminiferous tubules and interstitium per testis was determined by point counting method. Testis volume and sperm production/day was measured by routine techniques. The total number of Sertoli cells per testis was determined by morphometry(disector method). In experiment I and II, the volume density of seminiferous tubules and interstitium per testis was equal in control and treated testes. In experiment I (continuous exposure), the testis volume was increased by 14.8% (low dose)~16.5% (high dose), and sperm production/day and Sertoli cell numbers were increased 20.4~25%, and 32.6~39.4%, respectively. In experiment II (intermittent exposure), testis volume, sperm production/day and the total number of Sertoli cells per testis were not significantly different (p>0.05) in PCB-exposed rats (both low and high doses) compared to controls. It is clear that continuous exposure, but not intermittent exposure of male rats to Aroclor during the neonatalprepubertal period causes detrimental effects on the testis in adult male offspring. These results emphasize the susceptibility of the developing testis to environmental factors during the crucial neonatal period.