The MMP-9 Expression Of Mouse Embryos And The Regulation Of Le～Y And EGF On Embryo MMP-9 Secretion During Preimplantation

Embryo implantation in humans and rodents is a highly invasive yettightly controlled process. Successful implantation results from the fineregulated co-operation between the invasive blastocyst and the receptiveendometrium. Implantation is initiated, when direct interaction between embryo andthe uterus occurs, by the recognition of hatched, free embryo with thesurface of uterus. Matrix metalloproteinase (MMP) is a group of proteolyticenzymes, which function in the breakdown of extracellular matrix (ECM).MMPs involve in the embryonic implantation and placenta formation.Especially MMP-9 and TIMP-3 expressed by trophoblastocyst andendometrium locally can regulate the degradation of ECM. It has been shown LeY was regarded as a mediator to initiate theembryo attachment (provided by our lab). It caused the expression ofMMP-9 decrease in the embryo after LeY was blocked by anti- LeY mAbAH6 in vitro. We took the polyclonal MMP-9 antibody, EGF andmonoclonal antibody (mAb) AH6 directing to LeY oligosaccharide(Fuc-1-2 Gal 1-4 [Fuc 1-3] GlcNac) as tools and chose embryos in earlypregnancy (2-cell, 4-cell, 8-cell embryos, morulae and blastocysts) asobjects to study the embryo's growth, degradation abilities and secretion ofMMP-9. The major results are: 1. With the development of embryos, the embryonic secretion ofMMP-9 increased gradually. 2. The influence of LeY and EGF on the embryonic secretion ofMMP-9, ELISA revealed: 1) The embryonic secretion of MMP-9 in experimented group(blocked by AH6) was lower than control (without AH6 blocking),especially at 6 h. 2) After 3 hours' blocking by AH6, the experimented group (blockedby AH6) had higher level of MMP-9 than control while EGF was involvedin. 3) The embryonic secretion of MMP-9 in EGF blocked group(0.02ng/mL) was lower than control (0.037ng/mL), and the difference wassignificant (p<0.05). 3. The investigation of the secretion of pro-MMP-9 in single embryo:higher secreted group, 0.0335±0.0052ng/mL; lower secreted group, nosignal detected. And different embryo has different degradation abilitythough they are at the same developmental stage. With the development of the mouse embryo, the MMP-9 secretionlevel was increased to prepare for the embryo's mature and implantation.The existence of LeY and EGF functions in the embryonic development,attachment and implantation. These effects are not only necessary toembryo growth directly, but they also take effect on the embryoimplantation through MMPs indirectly. To quantitative analysis the MMP-9expression in early stage will probably provide us a functional marker indeciding embryo quality and instruct us in embryo choosing during IVF.