Expression of Matrix Metalloproteinase-7 and-26 in Cycling Human Endometrium

【Objective】To examine expression of MMP-7 and MMP-26 protein and mRNA in cycling human endometrium and early pregnancy deciduas.【Methods】Normal endometrial specimens(n=76) were classified according to an ideal 28-day reproductive cycle as early,mid and late proliferative phase,early,mid and late secretory phase,and menstrual phase.All samples were analyzed using Immunohistochemistry and RT-PCR.Rank test was used to evaluate the significance of differences between the groups.【Results】Immunostaining localized MMP-7 and MMP-26 in epithelial glandular and luminal cells.Semi-quantifications with RT-PCR and immunohistochemistry revealed maximal levels of MMP-7 in late secretory and menstrual phase whereas early and mid secretory phases had no MMP-7 signal.Expression of MMP-26 increased during proliferative phase to a maximum at mid-cycle,then decreased to non-detectable levels in the late secretory and menstrual phases.The decidual samples tested(n=9) had no signal of MMP-7 and MMP-26.The pattern of MMP-26 expression mimicked that of ER-α.【Conclusion】MMP-7 and MMP-26 proteins are both selectively localized in the epithelial compartment of normal endometrial tissue,but their expression patterns throughout the menstrual cycle are quite different.High expression of MMP7 in menstrual and proliferative phases suggests that MMP-7 be involved in the broken down and growing endometrium,whereas MMP-26 be involved in the implantation of endometrium since its peak expression at mid-cycle.