Activity of matrix metalloproteinase-2 and -9 and contents of their tissue inhibitors in uterine leiomyoma and corresponding myometrium.

OBJECTIVE

Matrix metalloproteinase-2 and -9 (MMP-2 and -9) are proteolytic enzymes degrading extracellular matrix proteins, mainly collagen type IV. Recent reports show that these proteases may be implicated in the growth of uterine leiomyoma. The aim of the present study was to evaluate the activity of MMP-2 and MMP-9, the contents of their tissue inhibitors (TIMP-1 and TIMP-2) and the immunolocalization of collagen type IV in uterine leiomyoma and corresponding myometrium.

METHODS

Material for the study comprised specimens of uterine leiomyomas and corresponding myometrium derived from 20 hysterectomized women. The activity of MMP-2 and MMP-9 in tissue extracts was evaluated by semi-quantitative zymography. TIMPs were measured by enzyme-linked inmmunosorbent assay. Protein immunohistochemistry was applied for detection of collagen type IV.

RESULTS

Activity and activation ratio of MMP-2 were significantly higher in leiomyomas than myometrium. The activity of MMP-9 was weak and did not differ between the investigated tissues. Contents of TIPM-1 and TIPM-2 were similar in both tissues. In both leiomyomas and myometrium, collagen type IV was localized in the extracellular matrix embedding bundles of smooth muscle cells, but was absent in areas of extracellular matrix accumulation within leiomyomas and in larger septa separating muscle fibers in normal myometrium.

CONCLUSIONS

MMP-2 may be implicated in pathogenesis of leiomyoma.