The effect of pre- and postnatal exposure to a mixture of daidzein and genistein on the reproductive system of male rats

Introduction: There is growing interest in the risk or benefits soybean food known as rich in isoflavones, due to their interactions with endogenous estrogen signal transduction pathway. Recent studies provide evidence that isoflavones can affect the reproductive and endocrine system under regular diet.

The aim of this study was to determine how the long-lasting administration of the key isoflavones, genistein and daidzein, may change morphology of the testis and the function of the epididymal antioxidant system of male rats.

Materials and methods: Male rats were treated by genistein and daidzein, in combination 2 (S2) or 20 (S20) mg/kg body weight per day for 5 days weekly mixed with regular rat chow from prenatal life until to sexual maturity. The control groups were fed without isoflavones.

Results: The findings show that the body, testis and cauda epididymis weights, testosterone level in blood plasma were

significantly lower than controls in the S20 group (p < 0.05). Also, superoxide dismutase activity in the epididymis, catalase activity in the testis, and glutathione peroxidase activity in the caput epididymis were significantly decreased (p < 0.05). Treating with these isoflavones significantly suppressed lipid peroxides levels in the epididymis (p < 0.05). Furthermore, presence of prematurely exfoliated gametogenic cells was observed in seminiferous tubules as well as the architectural disorganization of the seminiferous epithelium.

Conclusions: These findings suggest that isoflavones, if consumed chronically at a dose as for the S20 group may act not only as antioxidants, but they can be a risk for the male rats reproductive system dysfunction.