Effects of Prepubertal Exposure to Aroclor-1221 on Reproductive Development and Transcriptional Gene Expression in Female Rats

Polychlorinated biphenyls (PCBs), as persistent organic pollutants, are environmental endocrine-disrupting chemicals (EDCs). We aim to investigate the effects of prepubertal exposure to PCBs on the reproductive development and expression and regulation of related genes in rats. Female rats were treated with Aroclor-1221 (A-1221) (4 mg/kg/day, 0.4 mg/kg/day) or castor oil daily from postnatal day (PND) 28 for 2 weeks by gavage. Morphological, histological, hormonal, and biochemical parameters were studied. Lower weight and relative weight of hypothalamus, earlier puberty onset, a longer length of the estrous cycle, lower serum estradiol and progesterone levels, accelerated ovarian folliculogenesis, and higher apoptotic index in the ovary were found. The in vitro fertilization study showed a lower fertilization rate and cleavage rate. The genetic study revealed higher expression of Kiss-1 mRNA and lower expression of GnRH mRNA in the hypothalamus and higher expression of AMH mRNA and lower expression of C-myc mRNA in the ovary. These confirmed the reproductive damage of A-1221 in rats.