Morphological and Cytophysiological Changes in the Adult Rat Adrenal Medulla after Prenatal and Postnatal Exposure to Endocrine-Disrupting DDT

The aim of the investigation was to study morphological and cytophysiological changes in the adult rat adrenal medulla after prenatal and postnatal exposure to endocrine-disrupting chemical dichlorodiphenyltrichloroethane (DDT). Materials and Methods The experiment was carried out on male Wistar rats (n=30). The rats were exposed to low doses of DDT during prenatal and postnatal development (n=10) and during postnatal development (n=10) only. The average daily intake of DDT by rats was 3.30±0.14 μg/kg. The control (n=10) and experimental animals were sacrificed at the age of 10 weeks (post-puberty), when rat adrenal glands reached their maximum development. Histological samples of the equatorial sections of the adrenal glands were prepared. The adrenal medulla was studied using light microscopy and computer morphometry. Immunohistochemistry was performed to evaluate tyrosine hydroxylase expression in chromaffin cells. Plasma epinephrine content was measured using enzyme-linked immunosorbent assay. Results Postnatal exposure of rats to low doses of the endocrine disruptor was found to interfere with adrenal medulla development and cytophysiology of chromaffin cells. Prenatal and postnatal exposure resulted in more profound delay in adrenal medulla development of adult rats as compared to the values of rats exposed postnatally, which was manifested by reduced area of the adrenal medulla and reduced total area of chromaffin cells in its section. Postnatal exposure is manifested by more significant functional disorders including decreased synthesis of tyrosine hydroxylase enzyme in the cytoplasm of chromaffin cells and elevated number of tyrosine-hydroxylase-negative cells in the medulla section, leading to a decrease in plasma epinephrine concentration. Conclusion Exposure to low doses of DDT in the early stages of development leads to morphological and cytophysiological changes in the adult rat adrenal medulla and, therefore, reduced functional activity of chromaffin cells, which allows considering the endocrine disruptor DDT a potential risk factor disrupting the function of the neuroendocrine system.