Intravaginal Administration of Human Type III Collagen-Derived Biomaterial with High Cell-Adhesion Activity to Treat Vaginal Atrophy in Rats

Vaginal atrophy (VA) is the thinning and drying of the vaginal walls, which can lead to a variety of symptoms. VA is usually initiated by decreasing estrogen levels in post-menopausal women; so, the traditional treatment of VA is hormone therapy (HT). Here, we sought nonhormonal therapies aimed at treating this condition safely and effectively. Collagen is an excellent biomaterial and has important biological functions in skin and mucosal tissues. In particular, collagen can bind to epithelial cells to promote proliferation and differentiation. In this study, recombinant protein T16, which was derived from human type III collagen to provide potent cell-adhesion activity, was used as a safe alternative therapy to treat VA in ovariectomy rat models. After T16 was administered intravaginally for 2 weeks, the autologous collagen arrangement was improved in the epithelium and muscle layer of the rat vagina, and the thickness of epithelium tissue also increased significantly. Compared with the sham group, collagen therapy was found to influence the expression levels of several important proteins in the vaginal tissue, resulting in the upregulation of TIMP-1, Collagen I, Collagen III, Ki-67, VEGF, and AQP-2 and the downregulation of MMP-1 and IL-6. Cells in the collagen treatment group exhibited better proliferation and less apoptosis properties. These results not only provide support for additional animal experiments to further evaluate collagen therapy in VA treatment but also suggest the potential for wide applications of collagen biomaterials with high cell-adhesion activities.