IMMUNOLOCALIZATION OF THE MATRIX METALLOPROTEINASES GELATINASE-B AND STROMELYSIN-I IN HUMAN ENDOMETRIUM THROUGHOUT THE MENSTRUAL-CYCLE

Immunolocalization techniques were used to examine the distribution of the matrix metalloproteinases gelatinase B and stromelysin 1 in human endometrial specimens, taken across the normal menstrual cycle. Gelat inase B was produced by glandular epithelial cells for approximately 7 days during the proliferative phase, with polymorphonuclear leucocyte s, macrophages and eosinophils providing most of this enzyme at menstr uation. There was no evidence that gelatinase B is produced by stromal cells or mast cells during the cycle. Immunoreactive gelatinase B in glandular epithelial cells was greatest during the late proliferative phase and just after ovulation; its presence in glandular secretion an d the uterine fluid was optimal during the peri-implantation phase. Ge latinase B was clearly associated with an influx of polymorphonuclear leucocytes, macrophages and eosinophils just before, and during, menst ruation. In contrast, immunostaining for stromelysin 1 was much weaker than that for gelatinase B, and was present only around stromal cells and limited to microfocal locations at times coincident with stromal oedema (days 8-10 and 21-22). Both enzymes were widely distributed in specimens just before and during menstruation, and were particularly p rominent in connective tissue stroma and vascular basement membranes. Specimens at the early proliferative stage were devoid of both enzymes . The data provide further evidence supporting a role for metalloprote inases in endometrial biology, not only in matrix remodelling during t he cycle, but also in glandular secretions potentially relevant to bla stocyst recognition and implantation. Our observations emphasize the f unctional importance of specific cell types and the temporal regulatio n of gelatinase B and stromelysin 1 throughout the normal menstrual cy cle.