The effects of gestational and lactational exposure to Nonylphenol on c-jun, and c-fos expression and learning and memory in hippocampus of male F۱ rat

Objective(s): To investigate the effects of Nonylphenol (NP) in pups from dams exposed during gestational and lactational periods on immediate early genes (c-jun, c-fos) in hippocampus and the learning and memory of F۱ rats. Materials and Methods: Twenty eight pregnant dams, stratified by pregnancy date, were randomly assigned into ۴ groups, which were gavaged with NP at the doses of ۵۰ mg/kg/day, ۱۰۰ mg/kg/day, ۲۰۰ mg/kg/day and groundnut oil, respectively. Step-down avoidance test, and learning and memory effects of NP were evaluated on ۸-weeks-old pups. The expressions of c-jun and c-fos and the activities of choline acetyltransferase (ChAT) and acetylcholinesterase (AchE) were evaluated in hippocampus of pups. Results: Compared to the control, reaction time (RT) that pups spent to jump to the platform was longer (P=۰.۰۲), the number of errors were higher (P=۰.۰۱), and the step-down latency  was shorter in the ۲۰۰ mg/kg/day NP-treated group (P=۰.۰۴). Exposure to NP induced a significant reduction in ChAT activity in hippocampus in the ۱۰۰ (P=۰.۰۰۵) and ۲۰۰ mg/kg/day NP-treated groups (P=۰.۰۰۲), whereas exposure to ۲۰۰ mg/kg/day caused a significant increase in AchE activity (P=۰.۰۰۴); a dose–response relationship was revealed between ChAT and AchE activities and NP exposure in the hippocampus of pups (r=-۰.۸۲۱, P=۰.۰۱; r=۰.۷۵۷, P=۰.۰۴). Exposure to NP in the ۱۰۰ and ۲۰۰ mg/kg/day NP-treated groups exhibited an increase in number of c-fos and c-jun positive cells. Conclusion: Exposure to NP might negatively affect learning and memory ability in F۱ rats, possibly due to the alterations in the expression of c-jun and c-fos, and ChAT, AchE activities in hippocampus of pups.

Keywords:

Learning and memory , Neurotransmitters Nonylphenol , Pups