Matrix metalloproteinases and their tissue inhibitors in antegradely shed menstruum and peritoneal fluid

Objective: To investigate the expression of matrix metalloproteinases (MMPs ) and their tissue inhibitors (TIMPs) in antegradely shed menstruum and per itoneal fluid. Design: A cell biological and immunohistochemical study. Setting: Tertiary care university medical center. Intervention(s): Immunohistochemistry was performed on cryostat sections an d cultures of menstrual endometrium. Zymography was used to characterize MM P activity in peritoneal fluid, in menstrual serum, and in conditioned medi um. Western blot analysis was used to further identify the MMPs in these fl uids. Main Outcome Measure(s): Staining of MMPs and TIMPs in cryostat sections an d cultures and MMP expression and activity in peritoneal fluid and menstrua l blood serum. Result(s): Strong staining for MMP-1 and MMP-3 was observed in stroma and f or MMP-7 in epithelium. Matrix metalloproteinase-2 and MMP-9 were weakly ex pressed in stroma. Both TIMP-1 and TIMP-2 were expressed in menstrual endom etrium. Menstrual serum showed a pattern of MMP activity on zymography diff erent from peritoneal fluid. Western blot analysis showed the presence of M MP-7 and MMP 9 in menstrual serum. Conclusion(s): Antegradely shed menstrual endometrium expresses several MMP s and TlMPs, even after culturing for 24 hours. MMP activity in menstrual s erum is different from and more intense than MMP activity in peritoneal flu id. These enzymes may be involved in the early invasion of menstrual endome trium into the extracellular matrix of the peritoneum. (C) 2000 by American Society for Reproductive Medicine.