Matrix metalloproteinases-2, -7 and tissue metalloproteinase inhibitor-1 expression in human endometrium

Endometrium undergoes regular, cyclic tissue remodeling mostly associated to the endocrine system status. It is well-known fact that steroid hormones are strongly responsible for changes in endometrium. The precise mechanism of their action is still under investigation. The aim of the study was to evaluate the expression of metalloproteinases 2 and 7 (MMP-2, -7) and tissue inhibitor of metalloproteinase 1 (TIMP-1) in human endometrium in relation to serum concentrations of estradiol and progesterone during different phases of menstrual cycle.

The study material consisted of 52 biopsy samples; 12 obtained in the proliferative phase, 11 in the secretory phase and 29 during menstruation. Expression of MMP-2, MMP-7 and TIMP-1 was assessed by immunohistochemistry. Serum concentrations of estradiol and progesterone at time of biopsy were evaluated by immunochemistry assay. Results of the study were statistically assessed by linear regression model.

Increased serum concentration of estradiol was associated with increased MMP-2 expression in proliferative phase but decreased in secretory phase and during menstruation. No significant relationship was found between progesterone concentration and MMP-2 expression. Moreover, no difference in the expression of MMP-7 and TIMP-1 in the endometrium in relation to hormone levels and menstrual cycle phases were observed.

The results of the study indicate that estradiol influence MMP-2 expression in the endometrium depends on the phase of menstrual cycle. Such relationships were not found for MMP-7 and TIMP-1 and further tests clarifying association between estradiol and MMPs are needed.