College of Animal Science and Veterinary Medicine, Shandong Agricultural University, Tai'an City 271018, Shandong, P. R. China.
Laboratory Animal Center, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong, P. R. China.
J Reprod Dev. 2023 Aug 11;69(4):185-191. doi: 10.1262/jrd.2023-026. Epub 2023 May 26.
The mechanisms underlying postovulatory oocyte aging (POA) remain largely unknown. The expression of the calcium-sensing receptor (CaSR) in mouse oocytes and its role in POA need to be explored. Our objective was to observe CaSR expression and its role in the susceptibility to activating stimuli (STAS) in POA mouse oocytes. The results showed that, although none of the newly ovulated oocytes were activated, 40% and 94% of the oocytes recovered 19 and 25 h after human chorionic gonadotropin (hCG) injection were activated, respectively, after ethanol treatment. The level of the CaSR functional dimer protein in oocytes increased significantly from 13 to 25 h post hCG. Thus, the CaSR functional dimer level was positively correlated with the STAS of POA oocytes. Aging in vitro with a CaSR antagonist suppressed the elevation of STAS, and cytoplasmic calcium in oocytes recovered 19 h post hCG, whereas aging with a CaSR agonist increased STAS, and cytoplasmic calcium of oocytes recovered 13 h post hCG. Furthermore, the CaSR was more important than the Na-Ca exchanger in regulating oocyte STAS, and T- and L-type calcium channels were inactive in aging oocytes. We conclude that the CaSR is involved in regulating STAS in POA mouse oocytes, and that it is more important than the other calcium channels tested in this connection.
排卵后卵母细胞老化（POA）的机制在很大程度上尚不清楚。钙敏感受体（CaSR）在小鼠卵母细胞中的表达及其在 POA 中的作用需要进一步研究。我们的目的是观察 CaSR 的表达及其在 POA 小鼠卵母细胞中对激活刺激（STAS）的敏感性中的作用。结果表明，虽然没有新排卵的卵母细胞被激活，但在 hCG 注射后 19 和 25 小时分别用乙醇处理后，分别有 40%和 94%的卵母细胞被激活。hCG 注射后 13 至 25 小时，卵母细胞中 CaSR 功能二聚体蛋白的水平显著增加。因此，CaSR 功能二聚体水平与 POA 卵母细胞的 STAS 呈正相关。用 CaSR 拮抗剂进行体外老化可抑制 STAS 的升高和 hCG 注射后 19 小时卵母细胞胞质钙的升高，而用 CaSR 激动剂进行老化可增加 STAS 和 hCG 注射后 13 小时卵母细胞胞质钙的升高。此外，CaSR 在调节卵母细胞 STAS 方面比钠钙交换器更重要，并且在老化卵母细胞中 T 型和 L 型钙通道不活跃。我们得出结论，CaSR 参与调节 POA 小鼠卵母细胞中的 STAS，并且在这种情况下比其他测试的钙通道更为重要。
