Abstract: Objective：To detect the expression of matrix metalloproteinases-3（MMP-3）and tissue inhibitor of metalloproteinases-3（TIMP-3）in placenta of the patients with preeclampsia，and to investigate the role of MMP-3 and TIMP-3 in the pathogenesis of preeclampsia. Methods：The levels of MMP-3 and TIMP-3 in placental tissues were measured from 34 patients with preeclampsia（study group）and 32 normal pregnant women（control group）by immunohistochemistry. HE staining was used in order to count the number of the vessles. Results：MMP-3 and TIMP-3 were expressed in the decidual cell and the villous trophoblast in both group. Whether in decidual cell or in villi trophoblast cell，MMP-3 in preeclampsia group was significantly lower than that in the control group，but TIMP-3 was obviously higher in preeclampsia group. The count of vessels reduced in preeclampsia group. Conclusions：The differences of MMP-3 and TIMP-3 in placental tissues between preeclampsia group and control group suggest that those changes may associate with the pathogenesis of preeclampsia.

Key words: Pre-eclampsia, Matrix metalloproteinase 3, Tissue inhibitor of metalloproteinase-3, Placenta