Estrogen enhances penile healing and VEGF expression in rats

We recently provided the first evidence for significant ER expression and local estrogen synthesis in the penis of rat, adding the penis to the list of estrogen‐responsive tissues in males. Here, we begin a series of studies aimed at investigating the functional role of estrogen in the penis. In the present study, we hypothesize that estrogen plays some roles in maintaining the integrity of the glans penis. These roles may include facilitation of healing by regulating synthesis of factors involved in healing, such as vascular endothelial growth factor (VEGF). Lesions in the glans penises of anaesthetized castrated adult rats were made followed by administration of either 17 β‐estradiol (4mg/kg, in sesame oil) SC daily, for 4 days or vehicle only (control). The rats were sacrificed and glans penises harvested on day 1, 3 and 5 post‐lesioning, and tissues were processed for various analysis including scanning electron microscopy (SEM), confocal microscopy, histology and PCR. Penile healing in rats treated with 17 β‐estradiol was progressive and was complete by day 4, unlike in controls (which did not completely heal by day 4 post‐lessioning). Moreover, levels of VEGF mRNA and VEGF immunoreactivity were increased and pronounced, respectively, in estrogen‐treated rats compared to the control group. We conclude that estrogen may play a role in maintaining the integrity of glans penis, including healing, most likely, via VEGF. Sponsor: URC grant of Appalachian State University, Boone, NC