Prenatal bisphenol-A exposure altered exploratory and anxiety-like behaviour and induced non-monotonic, sex-specific changes in the cortical expression of CYP19A1, BDNF and intracellular signaling proteins in F1 rats

Abstract

Bisphenol-A (BPA) is one of the extensively studied estrogenic endocrine disrupting chemicals (EDC) with ubiquitous exposure among humans and wildlife. While there are literature reporting the association of dysregulated Brain-derived neurotrophic factor (BDNF) expression levels with altered cognitive and emotional behaviour such as anxiety-like and stress behaviour in animal models, there are no studies in BPA that investigate these altered neurobehavioural outcomes in parallel with the expression of intracellular proteins involved in BDNF signaling pathway. In this study, pregnant Wistar rats were exposed to BPA through water (25 μg/L, 250 μg/L, and 2.5 mg/L) during gestation day (GD) 9–21. Prenatal BPA exposure, increased anxiety-like behaviour in males and decreased exploratory behaviour in both male and female offspring. Downregulation of both BDNF and CYP19A1 genes were observed in male BPA-exposed offspring, whereas in females, the expression was upregulated. The expression of p-AKT, p-MEK and p-ERK proteins were increased in males, while in females, it decreased. Both the male and the female BPA-exposed offspring exhibited elevated levels of DNMT1 protein. The sex-specific alteration in the expression of CYP19A1 and DNA methyltransferase 1 (DNMT1) suggests that both hormonal and epigenetic dysregulation could underlie the long-term BPA-induced effect on anxiety-like behaviour in the offspring.