The mechanism underlying dibutyl phthalate induced shortened anogenital distance and hypospadias in rats

PurposeThe purpose of this study was to investigate the mechanism of dibutyl phthalate (DBP) induced hypospadias and shortened anogenital distance (AGD).MethodsAGD, hypospadias, and cryptorchidism incidence was observed in male offspring of DBP treated pregnant Wistar rats. Testicular development and testosterone levels of normal and DBP-treated rat embryos were compared.ResultsMale offspring of 300 mg and 900 mg DBP-treated pregnant Wistar rats exhibited shortened average AGD compared with the control group. A 22.7% hypospadias incidence was observed in the 300 mg group, but no offspring with cryptorchidism were identified. In the 900 mg group, hypospadias and cryptorchidism incidence reached 43.5% and 17.4%, respectively. Between E15.5 and E17.5, the 300 mg group exhibited delayed testicular development and testosterone secretion. However, testicular development and testosterone secretion subsequently recovered. The 300 mg treated and control groups had similar measures after E19.5. Contrastingly, testicular development and testosterone secretion were significantly diminished throughout development in the 900 mg group. Exogenous testosterone partially counteracted DBP-induced changes in the reproductive organs of male offspring of DBP-treated rats.ConclusionsHigh-dose DBP exposure may induce testicular dysgenesis in rat embryos. Additionally, low-dose DBP may delay testicular development and testosterone secretion during urethral development. This disruption may result in hypospadias.