Therapeutic effect of collagen on vaginal atrophy in ovariectomized rats

Abstract

Objective To evaluate the therapeutic effect of collagen on vaginal atrophy (VA) in ovariectomized rats. Methods Forty female SD rats were randomized into sham-operated group, VA model group, collagen group and estrogen group (n=10). In the latter 3 groups, rat models of VA were established by ovariectomy and treated with collagen or estrogen for 14 consecutive days starting from the 4th week after the operation. Body weight and vaginal pH ualue of the rats were measured daily, and the vaginal tissues were sampled after the treatments to examine the expression levels of PCNA, MMP-1, TIMP-1, COL-Ⅰ, COL-Ⅲ and TGF-β1 using immunohistochemistry; the mRNA expression levels of MMP-1, TIMP-1, COL-Ⅰ, COL-Ⅲ, and TGF-β1 were detected using real-time PCR. Western blotting was used to detect the protein levels of TGF-β1, Smad2/3 and p-Smad2/3 in the vaginal tissues. Results The vaginal pH ualue of the ovariectomized rats decreased obviously after collagen treatment, which significantly increased the thickness and proliferative activity of the vaginal epithelium, enhanced the synthesis and lowered the degradation of extracellular matrix components, and obviously increased the expression of phosphorylated Smad2/3 protein in the vaginal tissues. Compared with estrogen treatment, collagen showed less adverse effects on the uterus. Conclusion Collagen can effectively alleviate vaginal atrophy, increase extracellular matrix components in the vaginal tissue and promote the repair of vaginal epithelium in ovariectomized rats.

Keywords

• vaginal atrophy
• collagen
• transforming growth factor-β1
• smad protein