Cell-Free Fat Extract Prevents Vaginal Atrophy in Ovariectomized Model Via Promoting Proliferation of Vaginal Keratinocyte and Neovascularization.

BACKGROUND Most perimenopausal and post-menopausal women experience estrogen deficiency-induced vaginal atrophy. However, estrogen replacement therapy has contraindications and side effects, which makes it unsuitable for most women. Cell-free fat extract (CEFFE) has pro-proliferative and pro-angiogenic activities in tissue regeneration. OBJECTIVES The purpose of this study was to evaluate the effect of topical application of CEFFE in vagina and the effect of CEFFE to vaginal keratinocyte. METHODS The ovariectomized mice were treated with CEFFE via vaginal topical application for 2 weeks. The vaginal mucosal cell layer number, mucosal thickness, and vaginal collagen volume were determined using histological analyses. The vaginal mucosa proliferation and lamina propria angiogenesis were evaluated using anti-PCNA and anti-CD31 staining, respectively. For in vitro analysis, VK2/E6E7 cells were administered increasing CEFFE concentrations. Cell proliferation and cell cycle distribution were analyzed using CCK-8 assay and flow cytometry, respectively. Mucosal migration was evaluated using a wound healing assay. The expression of Ki-67, estrogen related proteins was detected using western blotting. RESULTS CEFFE-treated mice showed increased mucosal thickness and number of vaginal mucosal cell layers and reduced vaginal atrophy compared to ovariectomized mice. The number of PCNA-positive cells and CD31-positive capillaries also increased. In addition, CEFFE promoted the proliferation and migration of VK2/E6E7 cells, upregulated the expression of Ki-67, and inhibited the expression of estrogen relative proteins and PI3K/AKT pathway. CONCLUSIONS CEFFE prevents estrogen deficiency-induced vaginal atrophy by promoting vaginal mucosal proliferation and increasing neovascularization but not through the estrogen/estrogen receptor pathway in ovariectomized mice model.