Erectile dysfunction in hypospadiac male adult rats induced by maternal exposure to di-n-butyl phthalate

Abstract

For the treatment of hypospadias, a significant number of studies focus on penile reconstruction. However, scant attention is given to sexual behavior of hypospadiac patients and underlying mechanisms. A rat model of hypospadias was constructed by maternal di-n-butyl phthalate (DBP) exposure (800 mg/kg/day by gavage during gestational days 14–18). Ten-week-old male rats with hypospadias undertook significantly decreased penis/body weight ratio, reduced testis/body weight ratio, lower serum testosterone level and thinner myelin sheath thickness of cavernosum nerves. Meanwhile, erectile dysfunction (ED) was found in hypospadiac rats, which showed significant increases in transforming growth factor-β1 (TGF-β1) protein expression and decreases in the expression of alpha smooth muscle actin (α-SMA) protein, neuronal and endothelial nitric oxide synthase protein (nNOS and eNOS). In addition, phosphorylated protein kinase B/protein kinase B (pAkt/Akt) ratios were remarkably lower, but the Bcl-2-associated X protein (Bax)/Bcl-2 ratios, caspase-3 protein expression, nuclear factor erythroid 2-related factor 2/ Kelch-like ECH-associated protein 1 (Nrf2/Keap-1) ratios, NAD(P)H dehydrogenase quinone 1(NQO1) protein expression and heme oxygenase-1 (HO-1) protein expression were higher in the hypospadias groups than the control group. Notably, ED is comorbid with hypospadias in cases. Penile fibrosis, testosterone deficiency, and endothelial dysfunction lead to ED in hypospadias induced by DBP eventually, which might be explained by activating Akt/Bad/Bax/caspase-3 pathway, Nrf2/Keap-1 pathway and suppressing NOS/cGMP pathway in penis.