Effects of BPA on Notch1 Immunohistochemical Expression in Fetal and Neonatal Rat Brain

Abstract

SummaryBisphenol A (BPA) is a plasticizer found in reusable plastic containers, food and beverage cans, baby bottles and dental sealants. BPA exposure has become an important health concern based on its ability to “leach” from these products and penetrate the materials contained within them. Importantly, BPA can be transferred via placenta or lactation and this may affect the living body in intrauterine or lactation period.Notch signaling pathway to regulate cell fate by modulating differentiation, proliferation, and survival of cells. It has been reported that the members of Notch signaling are expressed in brain. Notch1 is a member of Notch signalling pathway, that expresses in subventricular zone, choroid plexus, grey matter, white matter, hippocampus and cerebral vessels of brain.In our study, we examined the effect of BPA on Notch1 expression in 5 different time intervals of fetal and neonatal periods in vivo. Wistar rats were used in this study (n=60). Five different experimental and control groups were formed. The experimental groups were treated with BPA at 50 mg/kg/day when control groups were treated with sesame oil and ethanol at 9:1 (vehicle). During the first part of the experiment, BPA or vehicle was applied to three groups at E 18-21, P 0-3 and P 4-7 periods. When BPA or vehicle were injected intraperitoneally to pregnant dams in E 18-21 group neonatal pups in P0-3 and P4-7 groups were given subcutaneous injections. The pups were sacrificed at the end of 7th day and their brain tissues were collected. During the second part of the experiment, similar applications with first experiment was performed. Following the application, pregnant dams were sacrificed and brain tissue of their fetuses were collected at E21stday and neonatal pups were sacrificed at P3rd day and their brains were collected. Notch1 expression was assessed by using immunohistochemistry. Notch1 was expressed in the pia mater, the grey matter, around ventricles (ventricular walls and sub ventricular zone) and in choroid and vascular plexus of brain.After BPA applications in fetal and neonatal periods, Notch1 expression was seen in different levels at E21st, P3rd and P7th days. In conclusion, the effects of BPA on Notch1 immunohistochemical expression in brain tissue, varies depends on exposure time and the developmental period during the exposure.