A physiologically relevant, estradiol-17 beta [E2]-responsive in vitro tissue-engineered model of the vaginal epithelium for vaginal tissue research

Aims There are many situations where preclinical models of the human vagina would be valuable for in vitro studies into the pathophysiology of vaginally transmitted diseases, microbicide efficacy, irritability testing, and particularly, for assessing materials to be inserted in the vagina for support of the pelvic floor. The aim of this study is to develop a physiologically relevant, low cost, and ethically suitable model of the vagina using sheep vaginal tissue (SVT) to reduce the need for animal testing in gynecological research. Methods Tissue-engineered (TE) vaginal models were developed by culturing primary vaginal epithelial cells and vaginal fibroblasts, isolated from the native SVTs on decellularized sheep vaginal matrices at an air-liquid interface. Morphological analyses of the models were conducted by performing hematoxylin and eosin staining and further characterization was done by immunohistofluorescence (IHF) of structural proteins and cytokeratins. Results Histological analysis of the models revealed a gradual formation of a stratified epithelium on our decellularized matrices and cell metabolic activity remained high for 21 days as measured by the resazurin assay. Our models showed a dose-dependent response to estradiol-17 beta [E-2] with an increase in the vaginal epithelium thickness and cellular proliferation under higher E-2 concentrations (100-400 pg/ml). The physiological relevance of these results was confirmed by the IHF analysis of Ki67, and cytokeratins 10 and 19 expression. Conclusion In this study, we have developed an estradiol-responsive TE vaginal model that closely mimics the structural and physiological properties of the native SVT.