[Expression of matrix metalloproteinase-9 and tissue inhibitor of metalloproteinase-3 protein in the implantation window phase of endometrium].

OBJECTIVE: To study the expression of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-3 (TIMP-3) protein in the implantation window phase of endometrium and the role of MMP-9 and TIMP-3 on embryo implantation. METHOD: Immunohistochemical analysis was employed to demonstrate the population of the MMP-9 and TIMP-3 positive cell in endometrium of different phases of menstrual cycle. RESULTS: The positive cells of these soluble proteinases were found to be located in the endometrial epithelial cells and stromal cells. The quantitative analysis of MMP-9 and TIMP-3 proteins demonstrated an increase in staining exent from proliferative endometrium to the endometrium of implatation window phase, and an decrease to late-secretory endometrium in comparison with the implantation window phase. CONCLUSION: Expression of MMP-9 and TIMP-3 in the implantation window phases of endometrium is specific and may play an important role in regulating the depth of trophoblast invasion during embryo implantation and may be involved in endometrial stromal breakdown during menstruation.