Daidzein impairs Leydig cell testosterone production and Sertoli cell function in neonatal mouse testes: An in vitro...

Isoflavone is a type of phytoestrogen that exists in soy‑based products. Previous studies have reported that certain foods containing isoflavones, particularly infant formula, may have potential adverse effects on male reproductive function. However, few studies have focused on the effects of isoflavones on testosterone biosynthesis and Sertoli cell function during the neonatal period. The aim of the present study was to investigate the influence of daidzein, a common isoflavone, on testosterone secretion and Sertoli cell function during the neonatal period. The organ culture method was used to assess the effects of daidzein on neonatal mouse testes. Cultured testes were treated with daidzein (0, 0.03, 0.3, 3 or 30 µmol/l) for 72 h. To verify the mechanism of action of daidzein on androgen production, Leydig cells were also treated with daidzein for 24 h. As anticipated, testosterone secretions were suppressed by daidzein (30 µmol/l) in cultured testes and Leydig cells. Further analysis demonstrated that the expression levels of steroidogenic acute regulatory protein (StAR), cholesterol side‑chain cleavage enzyme (P450scc) and 3β‑hydroxysteroid dehydrogenase (3β‑HSD), which are transport proteins and key enzymes in androgen biosynthesis, were suppressed in cultured neonatal mouse testes. In addition, the expression levels of StAR, P450scc, 3β‑HSD and 17α‑hydroxylase/20‑lyase were decreased in Leydig cells. Notably, proliferation of Sertoli cells was also inhibited by daidzein (30 µmol/l). Furthermore, the expression levels of vimentin were significantly suppressed in the testes following treatment with daidzein, whereas inhibin B expression exhibited no change. In conclusion, daidzein may suppress steroidogenic capability and impair Sertoli cell function in the neonatal period in vitro.