Prepubertal phthalate exposure can cause histopathological alterations, DNA methylation and histone acetylation changes in rat brain

Di-2-(ethylhexyl)phthalate (DEHP) is a phthalate derivative used extensively in a wide range of materials, such as medical devices, toys, cosmetics, and personal care products. Many mechanisms, including epigenetics, may be involved in the effects of phthalates on brain development. In this study, Sprague-Dawley male rats were obtained 21-23 days after their birth (post-weaning) and were exposed to DEHP during the prepubertal period with low-dose DEHP (DEHP-L, 30 mg/kg/day) and high-dose DEHP (DEHP-H, 60 mg/kg/day, 37 days) until the end of adolescence (PND 60). The rats in the study groups were sacrificed during adulthood, and histopathological changes, epigenetic changes, and oxidative stress parameters were evaluated in brain tissues. Histopathological findings indicating the presence of deterioration in brain tissue morphology were obtained, more prominently in the DEHP-H group. Examining the hippocampus under the light microscope, pyramidal neuron loss was detected only in CA1 of the DEHP-L group, while in DEHP-H rats, pyramidal neuron losses were detected in the CA1, CA2, and CA3 regions. No significant change was observed in brain lipid peroxidation levels with DEHP compared to control. Significant increases in total glutathione (GSH) in both dose groups were considered to be an adaptive response to DEHP-induced oxidative stress. The decrease in DNA methylation in the brain, although not statistically significant, and the increase in histone modification showed that exposure to DEHP may cause epigenetic changes in the brain and these epigenetic changes may also take place as one of the mechanisms underlying the damage observed in the brain. The results suggest that DEHP exposure during early development may have a significant effect on brain development.