Components of the plasminogen/plasmin system, known to be present in the oocyte, play a key role in maturation and fertilization. The objective of this study was to examine the effect of plasminogen activation and plasmin inhibition by exogenous supplementation of the IVF medium with streptokinase (SK) or ɛ-aminocaproic acid (ε-ACA), respectively, on fertilization parameters and preimplantation embryo development. After maturation, bovine cumulus-oocyte complexes (COCs) were inseminated in the presence of SK or ε-ACA. The addition of SK to the IVF medium facilitated the adhesion of the spermatozoa to the zona pellucida without affecting the percentages of monospermy. Cleavage rates and blastocyst yield were similar between the SK and Control groups while they were lower with the ε-ACA treatment. Additionally, we found that the expression levels of embryo quality-related genes ( and ) could be modified in blastocysts by the addition of SK or ε-ACA during IVF. The results obtained indicate that supplementation of the IVF medium with SK did not greatly alter the embryonic developmental parameters related to embryo quality in blastocysts. Moreover, we noticed that ε-ACA treatment compromises the success of embryo development, thus highlighting the importance of the plasminogen/plasmin activity during the early stages of embryogenesis in bovine.

中文翻译：

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牛体外受精过程中纤溶酶原激活和纤溶酶抑制：对受精参数和早期胚胎发育的影响

已知存在于卵母细胞中的纤溶酶原/纤溶酶系统的成分在成熟和受精中发挥关键作用。本研究的目的是通过在 IVF 培养基中外源补充链激酶 (SK) 或ε-氨基己酸 (ε-ACA) 来检查纤溶酶原激活和纤溶酶抑制对受精参数和植入前胚胎发育的影响。成熟后，牛卵丘-卵母细胞复合物 (COC) 在 SK 或 ε-ACA 存在下进行授精。在 IVF 培养基中添加 SK 促进精子与透明带的粘附，而不影响单精子的百分比。 SK 组和对照组之间的卵裂率和囊胚产量相似，而 ε-ACA 处理组的卵裂率和囊胚产量较低。此外，我们发现在 IVF 期间添加 SK 或 ε-ACA 可以改变胚泡中胚胎质量相关基因 ( 和 ) 的表达水平。获得的结果表明，在 IVF 培养基中添加 SK 并没有极大地改变与囊胚中胚胎质量相关的胚胎发育参数。此外，我们注意到ε-ACA处理会损害胚胎发育的成功，从而强调了纤溶酶原/纤溶酶活性在牛胚胎发生早期阶段的重要性。