Prenatal exposure to a single dose of testosterone adversely affects the oocyte and embryo quality in rats during adulthood: An experimental study

Background: Prenatal exposure to excess androgen can adversely affect the hypothalamic-pituitary-ovarian axis in the developing fetus, potentially leading to long-term reproductive system dysfunction in later life. Objective: We aimed to investigate whether prenatal exposure to a single dose of testosterone can affect the reproductive system, especially oocyte and embryo quality, and the ovarian expression of growth differentiation factor-9 (GDF-9) gene in rats during adulthood. Materials and Methods: In this experimental study, pregnant Wistar rats (12–13 wk, 185 ± 10 gr) in the experimental group (n = 5) subcutaneously received free testosterone (5 mg) on the 20th day of pregnancy, whereas controls received only solvent (n = 5). The offspring were evaluated for oocyte and embryo quality (zona pellucida thickness, number of normal fertilization, number of 2-cell embryos, and embryo arrest rate) and ovarian expression of GDF-9 gene during adulthood. Results: A significant increase was observed in the zona pellucida thickness (p = 0.02) in prenatally-androgenized (PNA) rats compared to controls. However, reductions in the number of normal fertilization and 2-cell embryos (p = 0.007, p = 0.01, respectively) in PNA rats compared to controls were observed. Furthermore, embryo arrest rate in PNA rats was significantly higher than in controls (p = 0.004). No significant difference was observed in the ovarian expression of GDF-9 gene in PNA rats compared to controls. Conclusion: Prenatal exposure to a single dose of testosterone during a critical window of fetal development significantly impairs oocyte and embryo quality in adult rats. Further studies are needed to validate these findings and to elucidate the underlying molecular and physiological mechanisms.