Abstract
Ethylbenzene is a hydrocarbon that is extensively used in both industry and in the home and has been reported as toxic to various tissues. Nevertheless, its effect on ovarian function remains unclear. For this purpose, we assessed ovarian tissue morphology, evaluated protein and gene expression related to folliculogenesis and steroidogenesis, and investigated the involvement of both apoptosis and autophagy processes in this effect. Female Wistar albinos rats were treated with 2000, 4000 and 8000 ppm doses of ethylbenzene by inhalation for 30 min daily for one month. Ovaries were then removed and proceeded for histopathological and molecular analyses. We found that ethylbenzene affected folliculogenesis by decreasing the number of growing follicles and increasing the number of abnormal follicles, leading to faster female reproductive aging. Interestingly, it disrupted female reproductive hormone balance, including progesterone, estradiol, testosterone and IGF-1 plasma levels. The latter protein, along with GDF-9, significantly decreased in all ethylbenzene-treated groups, leading to the disruption of follicular cell proliferation and development. TUNEL assay study showed that ethylbenzene exposure significantly increased the number of apoptotic cells. The mRNA levels of genes involved in granulosa cell proliferation and differentiation, such as INSL3, CCND2 and ACTB, were significantly decreased. In addition, LC3 protein expression increased, and its encoding gene was upregulated, suggesting that ethylbenzene treatment induced autophagy. In summary, ethylbenzene exposure caused structural and functional disorders of the ovary by disrupting the normal growth of follicles, altering reproductive hormone balance, inhibiting the expression of key reproductive proteins and triggering autophagy as well as apoptosis.