In mammals, the phenomenon of blastocyst hatching is an essential prerequisite for successful implantation. Blastocyst hatching is regulated by various molecules. Of them, cytokines, expressed by preimplantation embryos, are thought to be functionally important in blastocyst development and hatching, but their mechanistic roles are not clearly understood. Here, we examined the involvement of two cytokines, namely, interleukin‐1β (IL‐1β) and its natural antagonist, IL‐1ra, in blastocyst hatching in the golden hamster. Blastocysts expressed both cytokines and their receptor, IL‐1rt1. Supplementation of IL‐1β to cultured eight‐cell embryos improved blastocyst hatching (84.1% ± 4.2% vs. 66.6% ± 6.8%; treated vs. control). This improvement was diminished by IL‐1ra treatment (23.6% ± 12.9% vs. 76.4% ± 12.9%; treated vs. control). Interestingly, IL‐1β‐treated embryos showed increased messenger RNA expression of zonalytic proteases, that is, cathepsin‐L and ‐B by 1.9 ± 0.5‐ and 3.5 ± 0.1‐folds, respectively. This was accompanied by their increased enzyme activities; cathepsin‐L by 2.8 ± 0.7 fold and ‐B by 2.3 ± 0.7‐fold. Strikingly, proteases and IL‐1β were intensely colocalized to trophectodermal projections of hatching blastocysts. This is the first report to show the involvement of embryonic IL‐1β in regulating hatching‐associated proteases required for blastocyst hatching.

中文翻译：

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仓鼠囊胚孵化需要白细胞介素-1β的表达和功能：孵化相关组织蛋白酶的参与

在哺乳动物中，囊胚孵化现象是成功植入的必要先决条件。囊胚孵化受多种分子调控。其中，由植入前胚胎表达的细胞因子被认为在囊胚发育和孵化中具有重要的功能，但它们的机制作用尚不清楚。在这里，我们检查了两种细胞因子，即白细胞介素-1β (IL-1β) 及其天然拮抗剂 IL-1ra，在金仓鼠胚泡孵化中的作用。囊胚同时表达细胞因子及其受体 IL-1rt1。向培养的八细胞胚胎中补充 IL-1β 可改善囊胚孵化（84.1% ± 4.2% 与 66.6% ± 6.8%；治疗与对照）。这种改善因 IL-1ra 治疗而减弱（23.6% ± 12.9% 与 76.4% ± 12.9%；治疗与对照）。有趣的是，IL-1β 处理的胚胎显示带状分解蛋白酶的信使 RNA 表达增加，即组织蛋白酶-L 和-B 分别增加了 1.9 ± 0.5 倍和 3.5 ± 0.1 倍。这伴随着它们酶活性的增加；组织蛋白酶-L 增加 2.8 ± 0.7 倍，-B 增加 2.3 ± 0.7 倍。引人注目的是，蛋白酶和 IL-1β 强烈共定位于孵化囊胚的滋养外胚层突起。这是第一份显示胚胎 IL-1β 参与调节胚泡孵化所需的孵化相关蛋白酶的报告。蛋白酶和 IL-1β 强烈共定位于孵化囊胚的滋养外胚层突起。这是第一份显示胚胎 IL-1β 参与调节胚泡孵化所需的孵化相关蛋白酶的报告。蛋白酶和 IL-1β 强烈共定位于孵化囊胚的滋养外胚层突起。这是第一份显示胚胎 IL-1β 参与调节胚泡孵化所需的孵化相关蛋白酶的报告。