Yamada M, Horiuchi T, Oribe T, Yamamoto S, Matsushita H, Gentry P A
School of Bioresources, Hiroshima Prefectural University, Shobara-shi, Japan.
J Vet Med Sci. 1996 Apr;58(4):317-22. doi: 10.1292/jvms.58.317.
In this study fibrinolytic assay systems were used to assess the plasminogen activator (PA) potential and plasmin generating ability of oocyte-cumulus complexes isolated from preovulatory bovine follicles (2-8 mm diameter) and of fertilized oocytes from the day of fertilization up to, and including, the hatched blastocyst stage (day 12). During embryo development, the culture medium was changed every 24 hr and samples examined for PA activity. Irrespective of the stage of maturity, no plasminogen or PA could be detected in unfertilized oocytes from which the cumulus layer had been removed. Both plasminogen and PA were found in the cumulus layer indicating that this, rather than the oocyte, was the source of these proteins in the oocyte-cumulus complex. Following oocyte fertilization, no PA activity was detected in either the developing embryo or in the culture medium before day 7. When the embryos had developed to the expanded blastocyst stage, days 7-8, PA production began with activity being detected in both the embryos and their culture medium. Between days 8 and 12, when embryos had reached the hatched blastocyst stage, the PA activity had increased significantly (p<0.05). Analysis of the culture media confirmed this increase in production of PA activity and, based on zymography, it was estimated that the molecular weight of the PA was 78 k daltons.
在本研究中，使用纤维蛋白溶解测定系统来评估从排卵前牛卵泡（直径2 - 8毫米）分离出的卵母细胞 - 卵丘复合体以及从受精日直至包括孵化囊胚阶段（第12天）的受精卵母细胞的纤溶酶原激活物（PA）潜力和纤溶酶生成能力。在胚胎发育过程中，每24小时更换一次培养基，并检测样品的PA活性。无论成熟阶段如何，去除卵丘层的未受精卵母细胞中均未检测到纤溶酶原或PA。在卵丘层中发现了纤溶酶原和PA，这表明在卵母细胞 - 卵丘复合体中，这些蛋白质的来源是卵丘层而非卵母细胞。卵母细胞受精后，在第7天之前，发育中的胚胎或培养基中均未检测到PA活性。当胚胎发育到扩张囊胚阶段（第7 - 8天）时，PA开始产生，在胚胎及其培养基中均检测到活性。在第8天至第12天之间，当胚胎达到孵化囊胚阶段时，PA活性显著增加（p<0.05）。对培养基的分析证实了PA活性产生的这种增加，并且基于酶谱分析，估计PA的分子量为78千道尔顿。
