Regulation of the vitamin D receptor and cornifin beta expression in vaginal epithelium of the rats through vitamin D3

The aim of the present study was to determine the respective role of 1,25-dihydroxyvitamin D3 on vaginal epithelium and 1,25-dihydroxyvitamin D3 receptor expression in ovariectomized rats and vitamin D3 treated rats. Bilateral ovariectomies were performed in 20 mature, non-pregnant Wistar female rats. All the animals were divided into 2 groups consisting of 10 rats each. Group I served as control. In group II, animals were injected intramuscularly with vitamin D3 (50, 00 IU/kg). Two weeks after the injections, vaginas of animals in group I and group II were removed removed and processed for immunohistochemistry. Epithelial differentiation, 1,25-dihydroxyvitamin D3 receptor and cornifin beta expression were investigated in vaginal epithelium of control group (ovariectomized) and vitamin D3 treated rats. Vaginal epithelial cells from vitamin D3 treated animals changed into highly- stratified keratinizing layers. 1,25-dihydroxyvitamin D3 receptor and cornifin beta as a marker of squamous differentiation were present in ovariectomized rats treated with 1,25-dihydroxyvitamin D3. In contrast, cornifin beta and 1,25-dihydroxyvitamin D3 receptor were absent in all layers of vaginal epithelium in control group. We demonstrated for the first time that 1,25-dihydroxyvitamin D3 induced proliferation of vaginal epithelium consistent with the cornifin beta expression and 1,25-dihydroxyvitamin D3 up-regulated 1,25-dihydroxyvitamin D3 receptor expression in vaginal epithelium.