Effects of long-term high dose testosterone administration on vaginal epithelium structure and estrogen receptor-α and -β expression of young women

To date, the effects of long-term testosterone (T) administration on the human vagina are not completely understood. Thus, the aim of this study was to investigate the effects of long-term T treatment on vaginal tissue histology, estrogen receptor alpha (ER alpha) and beta (ER beta) expression and proliferation in female to male transsexual subjects (FtM). We compared vaginal samples from FtM subjects with those of premenopausal women (PrM) and postmenopausal women (M) not receiving any hormonal treatment for at least 2 years. Vaginal tissue samples from 16 FtM subjects treated with T (intramuscular injections of 100mg Testoviron Depot/7-10 days for at least 1 year), undergoing sex reassignment surgery, and 16 PrM and 16 M subjects undergoing a vaginal hysterectomy for prolapse, were collected. For each sample, morphology, glycogen content, proliferation (ki-67), ER alpha and ER beta expression were evaluated. Vaginal samples from FtM showed a loss of normal architecture of the epithelium, intermediate and superficial layers were completely lost, and glycogen content was depleted. T administration resulted in a strong proliferation reduction when compared with both M and PrM subjects. Stromal and epithelial ER alpha as well as ER beta were significantly decreased in FtM when compared with PrM subjects. In conclusion, our data suggests that systemic T administration at supraphysiological dosage, determines profound changes in histomorphology and reduces ERs expression and proliferation of vaginal epithelium.