Objective: To examine in juvenile rats the effect of perinatal exposure to a low dose of bisphenol A (BPA) on spatial memory and on the basal and stress-induced secretion of corticosterone in plasma.
Methods: Female Wistar rats were exposed to BPA (40 microg/kg provided through corn flakes) from gestational day 1 to the end of lactation. At postnatal day 42, their offspring were randomly divided into two groups per sex. The one group was sacrificed under basal conditions and the other group was tested in the Y maze task and sacrificed immediately afterwards. Trunk blood was collected for corticosterone determinations by radioimmunoassay.
Results: BPA-treated animals of both sexes exhibited a reduced exploration attitude during the Y maze test vs. same sex controls. BPA exposure impaired spatial memory and novel arm discrimination, as BPA-treated animals of both sexes showed no significant preference for visiting the novel arm during the Y maze test, compared to the same sex controls. Exposure to BPA significantly increased basal corticosterone levels of females vs. non-treated females (Table 1). Following Y-maze, the BPA-treated, but not the non-treated males, exhibited significantly elevated corticosterone levels. Pubertal females, irrespective of perinatal treatment, showed elevated corticosterone levels following the test. However, this increase was significantly higher in BPA-treated females, as compared to the non-treated animals.
Table 1: Corticosterone levels in control and BPA animals. Mean ±SEM; 2-way ANOVA; *p≤0.05.
Plasma corticosterone | Male Control | Male BPA | Female Control | Female BPA |
Basal (ng/ml) | 187±28 | 151±33 | 141±29 | 338±66* |
Post Y maze test | 251±24 | 410±58* | 336±31 | 449±23* |
Conclusion: Perinatal exposure of rats to a low dose of BPA can modify spatial memory and plasma corticosterone secretion at the onset of puberty in a sexually dimorphic manner.