Mechanism of Effects of Genistein on the Reproductive System of Prepubertal Male Rats

  Objective  To study the effects of genistein (GEN) on reproductive system in prepubertal male rats.

  Methods  Thirty SPF-rated male SD rats were randomly divided into control group (Con group), low-dose group (G1 group) and high-dose group (G2 group), with 10 rats in each group. Corn oil, 150 mg/kg and 300 mg/kg GEN dissolved in corn oil of equal volume were respectively administered every day and weighed the next day. After 6 weeks, the rats were sacrificed, and the testis, epididymis and prostate were dissected, and organ coefficients were calculated. Histopathological changes of testis was observed. The number of sperm was counted and the rate of sperm malformation was calculated. The concentrations of serum testosterone and estradiol were detected by radioimmunoassay. The protein phosphatase 2, regulatory subunit B, gamma (PPP2R2C) protein expression in testicular tissue was detected by immunofluorescence assay. The mRNA and protein expression levels of PPP2R2C and cyclin dependent protein kinases 2 (CDK2) in rat testis were detected by real-time quantitative fluorescence PCR (RT-qPCR) and Western blot, respectively. The protein phosphatase 2A (PP2A) activity in testicular tissue was detected by immunoprecipitation.

  Results  There were no statistically significant differences in body mass, sperm number, serum estradiol and PP2A enzyme activity among the groups (P>0.05). The pathological structure of testicular in G2 group was disordered. Sperm abnormality rate in G1 and G2 groups was higher than that in Con group (P<0.05). Serum testosterone concentration in G2 group was lower than that in Con group (P<0.05). The expression of PPP2R2C and CDK2 in G2 group was higher than that in Con group (P<0.05), but the protein level was lower than that in Con group (P<0.05). PPP2R2C protein was expressed in testicular tissue in each group.

  Conclusion  Long-term exposure to high dose (300 mg/kg) GEN during prepuberty may cause adverse effects on reproductive function in adult male rats. Further investigation is needed to determine whether PPP2R2C-PP2A-CDK2 phosphorylation pathway affects reproductive system in rats.