Italian Journal of Animal Science (Dec 2024)

Calcium promoting maturity of oocytes through calcium/calmodulin-dependent protein kinase II of yak (Bos grunniens)

  • Yahua Yang,
  • Zhou Chen,
  • Chongfa Yang,
  • Hao Chen,
  • Xiaochen Song,
  • Yang Li,
  • Bingzhu Zhao,
  • Junyuan Ma,
  • Jine Wang,
  • Yanmei Yang,
  • Shengdong Huo,
  • Wenxue Luo

DOI
https://doi.org/10.1080/1828051X.2024.2358869
Journal volume & issue
Vol. 23, no. 1
pp. 895 – 906

Abstract

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Yaks (Bos grunniens) are the most economically important mammals on the Xizang Plateau, providing milk, meat and income for people. The molecule CaMKII is key to the cellular Ca2+ signalling pathway, which can regulate intracellular environmental homeostasis and bind to a variety of proteins to regulate the location, activity and function of proteins. Calcium as Ca2+ controls the maturation process of oocytes, maintains fertilisation and initiates embryonic development. In this study, immunohistochemistry was used to detect the location and expression of CaMKII at different stages of follicular development. The activator as Ca2+ at 0.20, 0.22 and 0.24 mM and the inhibitor KN-93 at 0.5, 1.0 and 1.5 μM were added to compare maturation rate of oocytes in vitro. Immunofluorescence staining analysed the antioxidant levels of reactive oxygen species (ROS) and glutathione (GSH) and the expression of CaMKII in the mature oocytes.The growth related genes c-fos, epidermal growth factors EGF and EGFR and apoptotic genes BAX, BCL-2, were detected in mature oocytes after 24 h of culture using a real-time quantitative polymerase chain reaction. The results showed that CaMKII was widely distributed in follicular tissues. The oocyte maturation rate was the highest at 58.43 ± 3.37% when the culture temperature was 38.5 °C and 57.6% when the concentration of FBS was 15%, significantly higher than 55.6% at 10% and 53.8% at 20% (p < 0.05). The GSH level of mature oocytes reached the highest value in 0.24 mM Ca2+ group. The ROS level of mature oocytes reached the highest level in 1.5 μM KN-93 group, and the expression of BCL-2, EGF, EGFR and c-fos mRNA was increased by adding Ca2+.The KN-93 decreased the expression of BCL-2, EGF, EGFR and c-fos genes. The study showed that Ca2+ could regulate the levels of GSH and ROS by activating CaMKII, activity and it improved the maturation rate of oocytes in vitro.

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