Bisphenol A and dibutyl phthalate affect the expression of juxtacrine signaling factors in rat testis

The study was designed to examine the effects of model plastic derived compounds, bisphenol A (BPA) and dibutyl phthalate (DBP), on juxtacrine communication in adult rat testis, by evaluating the expression of Notch pathway components. Testicular explant were exposed in vitro to BPA (5 × 10−6 M, 2.5 × 10−5 M, 5 × 10−5 M) or DBP (10−6 M, 10−5 M, 10−4 M) for 24 h. To determine the expression of Notch1, Dll4, Hey1, Hes1 and Hey5 real-time RT-PCR was used. Protein levels and localization of NOTCH1 receptor, its ligand DLL4 as well as HEY1, HES1 and HEY5 factors were detected by western blot analysis and immunohistochemistry, respectively. Upregulation of Notch1, Dll4 and Hey1 at the mRNA and protein level was demonstrated in testis explants after BPA and DBP treatment (p < 0.05; p < 0.01; p < 0.001). Hes5 expression decreased after BPA (p < 0.05; p < 0.01; p < 0.001), whereas Hes1 expression was not altered by either BPA or DBP. Tested chemicals altered immunoexpression of activated NOTCH1, DLL4, HEY1 and HES5 both in seminiferous epithelium and interstitial tissue, exerting differential effects on particular cell types. In conclusion, BPA and DBP affect Notch signaling pathway in rat testis, which indicates that juxtacrine communication is a potential target for the action of plastic derived compounds in male gonad.