Mechanism of androgen in improving erectile dysfunction in castrated rats by regulating androgen receptor/vascular endothelial growth factor

Abstract

Objective: To explore the mechanism of androgen in improving erectile dysfunction in castrated rats. Methods: Forty 8-week-old male Sprague-Dawley (SD) rats were randomly divided into 4 groups:normal control group (Group A); castration group (Group B, in which rats were castrated); intervention groups (group C and D), in which rats were treated with different concentrations of testosterone undecanoate orally every day at 10 mg/kg (low dose) and 20 mg/kg (high dose), respectively after being castrated. Animals in group A and B were given 0.9% NS instead. After 8-week treatment, the level of serum testosterone, intra cavernous pressure (ICP) and mean arterial pressure (MAP) were detected, and the expression of androgen receptor (AR)and vascular endothelial growth factor (VEGF) were detected in the penis by Immunohistochemistry and Western blot. Results: The level of serum testosterone was significantly lower in group B [(1.3±0.6) nmol/L] than in group A [(17.1±1.5) nmol/L] (P<0.05).After testosterone supplementation, serum testosterone levels in group C [(8.7±1.2) nmol/L] and group D [(15.5±1.6) nmol/L] were higher than that in group B (all P<0.05). Max ICP/MAP of group C and D were higher than that in group B (all P<0.05). Immunohistochemistry and Western blot showed that the expression levels of AR and VEGF in group B were significantly lower than those in group A, C and D, and group D > group C (all P<0.05). Conclusion: Androgen replacement therapy with testosterone undecanoate can improve the erectile function of castrated rats by protecting the integrity of endothelial cells through AR/VEGF pathway.