Objective During and after menopause, the symptoms of vaginal atrophy cause great discomfort and necessitate effective treatment options. Currently, vaginally applied oxytocin is being investigated as a treatment for the symptoms of vaginal atrophy in postmenopausal women. To clarify the mechanisms behind oxytocins effects on vaginal atrophy, the present study investigated the effects of oxytocin on cell proliferation in the cells of the Vk2E6E7 line, a non-tumour vaginal cell line. The study also compared the effects of oxytocin with those of estradiol (E2). Study design The effects of both oxytocin and E2 on the proliferation of Vk2E6E7 cells were investigated using Cell Proliferation ELISA BrdU Colorimetric Assay. The expression of both oxytocin and oxytocin receptor was studied in Vk2E6E7 cells using quantitative real-time polymerase chain reaction and immunofluorescent staining. Main outcome measures Cell proliferation and gene expression. Results Oxytocin increased cell proliferation both time dependently and dose dependently. This differed from the effect pattern observed in cells treated with E2. In addition, in oxytocin-treated cells, the oxytocin receptor was found to be co-localized with caveolin-1, indicating pro-proliferative signalling within the cell. Conclusions Oxytocin stimulates cell proliferation and the co-localization of oxytocin receptor with caveolin-1 in oxytocin-treated cells, supporting the role of oxytocin signalling in cell proliferation. In addition, these findings suggest that increased cell proliferation is one mechanism by which local vaginal oxytocin treatment increases vaginal thickness and relieves vaginal symptoms in postmenopausal women with vaginal atrophy.
Oxytocin receptor elicits different EGFR/MAPK activation patterns depending on its localization in caveolin-1 enriched domains