Zhang X, Kidder G M, Zhang C, Khamsi F, Armstrong D T
Department of Physiology, University of Western Ontario, London, Canada.
J Reprod Fertil. 1994 May;101(1):235-40. doi: 10.1530/jrf.0.1010235.
Plasminogen activator has been implicated in tissue invasion and remodelling because of its role in the degradation of the extracellular matrix. Its activity can be detected in mouse embryos as early as day 6 of pregnancy, suggesting that plasminogen activator is involved in the process of implantation. The present study determined the time course of expression of the genes encoding tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) during the preimplantation period in rats by the sensitive mRNA phenotyping procedure of reverse transcription-PCR. The tPA mRNA was present in rat oocytes and two-cell embryos, but was not detected between the four-cell and blastocyst stages. The uPA mRNA was first detected in two-cell rat embryos, and was present through to the blastocyst stage. In chromogenic assays, plasminogen activator activity was detected in oocytes and embryos between two-cell and blastocyst stages. Most plasminogen activator activity present in preimplantation embryos appeared to be uPA, as it could be inhibited by anti-uPA antibody and a specific uPA inhibitor, amiloride, but not by anti-tPA antibody. The present data demonstrate the expression of uPA gene and uPA activity in preimplantation rat embryos, suggesting that embryonic uPA may be involved in early embryo development and implantation.
由于纤溶酶原激活剂在细胞外基质降解中发挥作用，它与组织侵袭和重塑有关。早在怀孕第6天就能在小鼠胚胎中检测到其活性，这表明纤溶酶原激活剂参与了着床过程。本研究通过逆转录 - PCR这种灵敏的mRNA表型分析方法，确定了大鼠着床前期编码组织型纤溶酶原激活剂（tPA）和尿激酶型纤溶酶原激活剂（uPA）的基因的表达时间进程。tPA mRNA存在于大鼠卵母细胞和二细胞胚胎中，但在四细胞期和囊胚期之间未检测到。uPA mRNA最早在大鼠二细胞胚胎中被检测到，并且一直存在到囊胚期。在显色分析中，在卵母细胞以及二细胞期到囊胚期的胚胎中检测到了纤溶酶原激活剂活性。着床前胚胎中存在的大多数纤溶酶原激活剂活性似乎是uPA，因为它能被抗uPA抗体和特异性uPA抑制剂阿米洛利抑制，而不能被抗tPA抗体抑制。目前的数据证明了uPA基因在大鼠着床前胚胎中的表达以及uPA活性，这表明胚胎uPA可能参与早期胚胎发育和着床。
