Light and Transmission Electron Microscopic Studies on Subacute Toxicity of Bisphenol A on the Rat Ovary.

Objective: To investigate subacute toxicity of Bisphenol A (BPA) in adult rat ovaries using gastric intubation daily for 4 weeks by light and transmission electron microscopy.

Study Design: Fifteen rats were included in the study and divided into 2 groups: 12 rats were used for BPA administration (600 mg/kg body weight), and 3 rats received only vehicle and served as controls. The ovaries of both treated and control rats were taken at 1, 2, 3, and 4 weeks postadministration, fixed in 10% neutral buffered formalin, and processed for light microscopy. Ovarian samples at the 4th week postexposure were fixed in 3% glutaraldehyde and processed for transmission electron microscopy.

Results: The main histopathological alterations were observed at the 3rd and 4th weeks postexposure. Atretic follicles,formation of cysts, separation of granulosa cells, and hyperemia of blood vessels were observed. Moreover, a marked increase in the thickness of the tunica albuginea was determined (33.8 ± 1.72 μm and 34.8 ± 1.72 μm, respectively,for the 3rd and 4th weeks as compared to the control group (13.78 ± 0.12 μm). Transmission electron microscopy showed marked lipid droplet accumulation, chromatin condensation in the nuclei of granulosa cells, and presence of autophagosomes in the treated group at 4 weeks postexposure as compared to the nonexposed group (control group).

Conclusion: The results of the present study suggest altered or disrupted ovulation. Moreover, change in the thickness of the tunica albuginea observed during the course of exposure may play a role in such disrupted ovulation.