Toxic effect of gestational exposure to nonylphenol on F1 male rats.

Objective: The purpose of this study was to examine whether gestational exposure to major environmental endocrine-disrupting chemicals, nonylphenol (NP), would lead to nerve behavioral and learning and memory capacity alterations in the male offspring of rats, and reproductive development alterations in the male offspring of rats.

Methods: Dams were gavaged with NP at a dose level of 50 mg/kg/day, 100 mg/kg/day or 200 mg/kg/day daily from gestational day 9 to 15, and at a dose level of 40 mg/kg/day, 80 mg/kg/day or 200 mg/kg/day daily from gestational day 14 to 19 (transplacental exposures).

Results: Exposure to 200 mg/kg/day NP produced a significant decrease in learning and memory functions in offspring rats (P<0.05) in Morris water maze task, as demonstrated by the increased escape latency and number of error. In Step-down Avoidance Test, offspring rats exposed to NP spent more reaction time (RT) and presented lower latency to first step-down than the control offspring (P<0.01). In utero exposure to 80 and 200 mg/kg/day NP produced a significant decrease in the number of live pups per litter and ratio of anogenital distance to body length on PND 0 (P<0.05), and also testes and prostate weight, activities of ALP, plasma testosterone concentration, cauda epididymis sperm counts, daily sperm production et al. respectively on PND 90 (P<0.05). Histopathological examination of the brain biopsy illustrates that exposure to NP at high dose induces the presence of abnormal distribution of spermatozoa showed in lumina of the seminiferous tubules, and absence of spermatogenesis and spermiogenesis.

Conclusion: Gestational exposure to nonylphenol might induce neurotoxic and reproductive toxic effects on F1 male rats.