Matrix metalloproteinase messenger RNA expression in human endometriosis grafts cultured on a chicken chorioallantoic membrane

OBJECTIVE: To investigate the role of matrix metalloproteinase 1 and 2 (MMP-1/MMP-2) in human endometrial explants in a chicken chorioallantoic membrane model (CAM) of endometriosis. DESIGN: Experimental prospective study. SETTING: University hospital. PATIENT(S): Endometrium samples obtained from ovulating women, both healthy and patients with endometriosis, who were undergoing curettage and diagnostic laparoscopy for benign gynecologic conditions. INTERVENTION(S): Endometrial grafts were transplanted to the CAM and cultured for 0, 24, 48, 72, and 96 hours. MAIN OUTCOME MEASURE(S): Expression of MMP-1 and MMP-2 messenger RNA (mRNA) was quantified by competitive reverse-transcriptase polymerase chain reaction (RT-PCR) and normalized to expression of the housekeeping gene human glyceraldehyde 3-phosphate dehydrogenase (GAPDH) mRNA. RESULT(S): All grafts expressed MMP-1 and MMP-2 mRNA. The endometrium of healthy women and patients with endometriosis showed a statistically significant increase of MMP-1 mRNA expression 24, 48, 72, and 96 hours after transfer to the CAM. An increase of MMP-2 mRNA expression was only detected after 96 hours of CAM culture in patients with and without endometriosis. No statistically significant difference regarding the MMP-1 and MMP-2 mRNA expression could be shown in healthy women or endometriosis patients. CONCLUSION(S): Our data suggest that MMP-1 and MMP-2 are major factors involved in the invasion of endometrium into the peritoneum and in vascularization of endometriosis. Whether MMPs are suitable targets for treatment of endometriosis has to be examined in further studies.