Lei H, Vadillo-Ortega F, Paavola L G, Strauss J F
Department of Obstetrics and Gynecology, University of Pennsylvania School of Medicine, Philadelphia, USA.
Biol Reprod. 1995 Aug;53(2):339-44. doi: 10.1095/biolreprod53.2.339.
The fetal membranes undergo striking changes in structure before delivery that involve catabolism of the extracellular matrix. To investigate the role of specific enzymes in this process, we examined gelatinase activities in rat amnion, visceral yolk sac placenta, and placenta and amniotic fluid between Days 18-21 of pregnancy. Matrix metalloproteinase (MMP)-2 was present in amnion on all days, and its activity increased slightly on Day 21. The 92-kDa gelatinase, MMP-9, was not detected on Days 18-20 but appeared by the morning of Day 21. There was a marked increase in MMP-9 mRNA in the amnion on Day 20, preceding the appearance of MMP-9 activity. Western blotting confirmed an increase in MMP-9 protein in amnion on Day 21. MMP-2 and MMP-9 activities were detected in extracts of whole yolk sac placenta, placenta, and amniotic fluid, but there were no striking changes in these gelatinases between Days 18 and 21. However, the capsular regions of the visceral yolk sac placentae, which thin and rupture during labor, did show higher MMP-9 activity on Day 21 than on Days 18 and 20. We suggest that the striking increase in MMP-9 expression in amnion and possibly the capsular region of the visceral yolk sac placenta approximately 12 h prior to delivery is responsible, in part, for the alterations in the structure of these fetal membranes before parturition.
胎膜在分娩前会经历显著的结构变化，这涉及细胞外基质的分解代谢。为了研究特定酶在此过程中的作用，我们检测了妊娠第18 - 21天大鼠羊膜、脏层卵黄囊胎盘、胎盘和羊水的明胶酶活性。基质金属蛋白酶（MMP）-2在所有天数的羊膜中均有存在，其活性在第21天略有增加。92 kDa的明胶酶MMP - 9在第18 - 20天未检测到，但在第21天早晨出现。在第20天，羊膜中MMP - 9 mRNA显著增加，早于MMP - 9活性的出现。蛋白质印迹法证实第21天羊膜中MMP - 9蛋白增加。在全卵黄囊胎盘、胎盘和羊水的提取物中检测到MMP - 2和MMP - 9活性，但在第18天和第21天之间这些明胶酶没有显著变化。然而，在分娩时变薄并破裂的脏层卵黄囊胎盘的包膜区域，在第21天确实显示出比第18天和第20天更高的MMP - 9活性。我们认为，在分娩前约12小时羊膜以及可能脏层卵黄囊胎盘的包膜区域中MMP - 9表达的显著增加，部分导致了这些胎膜在分娩前结构的改变。
