Intracavernosal injection of vascular endothelial growth factor improves erectile function in aged rats.

Abstract

To investigate whether intracavernosal injection of vascular endothelial growth factor (VEGF) can restore erectile function in the aging rat. Ten young (4-5 months) and 30 old (24 months) Sprague-Dawley male rats were used. The old rats were divided into 3 groups: vehicle-only (phosphate buffered saline plus 0.1% bovine serum albumin; n = 10), VEGF 1 microg/kg (n = 10), and VEGF 10 microg/kg (n = 10). At 2 and 4 weeks after treatment, erectile function and histology were evaluated by hemodynamic study, histomorphometric analysis, and immunohistochemistry. After 4 weeks of treatment, the ratio of peak intracavernosal pressure to systemic arterial blood pressure in response to neurostimulation was significantly higher in both the VEGF 1 microg/kg (79.9 +/- 7.7%) and the VEGF 10 microg/kg group (76.8 +/- 5.8%) compared to the vehicle-only group (63.1 +/- 8.5%; p < 0.05). The percentage of cavernosal smooth muscle was significantly higher in the VEGF 10 microg/kg group (16.1 +/- 1.4%) compared to the vehicle-only group (12.8 +/- 2.2%; p = 0.047). VEGF treatment in old rats increased e-NOS and VEGF expression in both treatment groups. Intracavernosal injection of VEGF appears to restore smooth muscle integrity and improve erectile function in aged rats.