Matrix metalloproteinase-26 (MMP-26, endo-metase and matrilysin-2), a novel member of the MMPs family, is detected not only in the placenta and uterus, but is widely expressed in malignant tumors from different sources as well as in diverse tumor cell lines. However, the function of MMP-26 in the reproductive system has never been reported. Expression of MMP-26 in mouse embryos and the function of the MMP-26 antibody during mouse embryo implantation was examined for the first time by injecting the uterine horn, immunohistochemistry, in situ hybridization, co-culture of mouse blastocysts and uterine monolayer epithelial cells, Western blot, RT-PCR, Northern blot and zymography. Our results show that there is strong expression of MMP-26 niRNA and protein in the mouse embryo. Furthermore, the MMP-26 antibody dramatically inhibited mouse embryo implantation and significantly inhibited adhesion and outgrowth of mouse blastocysts on in vitro uterine monolayer epithelial cells. At the same time, the MMP-26
