Abstract
Background
To investigate the impact of perinatal exposure to a low dose of bisphenol A (BPA) on spermatogenesis in male rats and the underlying mechanism.
Methods
Female rats were injected subcutaneously with 2 µg BPA/kg/day from gestation day 10 through lactation day 7. The spermatogenesis and expression of key regulatory genes in the testes as well as the central modulators of the hypothalamic-pituitary-gonadal axis were determined in male offspring on postnatal day 18, 21, and 24 (PND18, 21, and 24).
Results
1) Perinatal BPA exposure led to an increase in the weight of body and testis in PND21-24 male offspring. The seminiferous tubular diameter and the number of round spermatids were significantly increased in PND21 BPA-rats, while the volumes of the Sertoli cells, spermatogonia and spermatocytes were not significantly altered. 2) Compared to the control rats, the expression levels of key meiotic regulators such as cyclinA1, c-jun and c-fos in the seminiferous tubules were significantly elevated in PND21 BPA-rats. 3) The plasma levels of FSH and LH (PND21 and PND24) as well as the frequency of pulsatile LH secretion (PND21) were significantly increased in BPA-rats, although the plasma levels of testosterone and estrogen showed no significant difference between the two groups. 4) In comparison with control rats, the levels of GnRH mRNA in the preoptic area (POA) and kiss1 mRNA in arcuate nucleus (ARC) were significantly increased in the BPA-rats, whereas the level of ERα mRNA in ARC was decreased, although the number of GnRH-positive cells and ARC kisspeptin-positive cells were unchanged. Interestingly, neither the number of kisspeptin-positive cells nor the level of kiss1 mRNA in the anteroventral periventricular nucleus (AVPV) showed a difference between the two groups.
Conclusion
Perinatal exposed to a low dose of BPA leads to an increased meiosis of spermatocytes and promotes the spermatogenesis in male offspring, most likely through activation of the hypothalamic-pituitary-gonadal axis.
Perinatal Exposure to Low-Dose Bisphenol A Impairs Spatial Learning and Memory in Male Rats