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ORIGINAL RESEARCH article

Front. Cell Dev. Biol.

Sec. Embryonic Development

This article is part of the Research TopicMetabolic Pathways in Early Embryogenesis: Mechanisms and ImplicationsView all 3 articles

Multi-omics Analysis Reveals a Protective Role of Endogenous Proline in Sheep Oocyte Vitrification and its Therapeutic Application

Provisionally accepted
Airixiati  DilixiatiAirixiati DilixiatiXi  ZhaoXi ZhaoAikebaier  AihemaitiAikebaier AihemaitiWeijian  LiWeijian Li琛  樊琛 樊Guodong  ZhaoGuodong ZhaoAbulizi  WusimanAbulizi WusimanXuguang  WangXuguang Wang*
  • Xinjiang Agricultural University, Ürümqi, China

The final, formatted version of the article will be published soon.

Vitrification is a rapid-cooling cryopreservation technique for oocytes and a key method in assisted reproductive technology (ART). During vitrification, oocytes are exposed to high concentrations of cryoprotectants, leading to cryoinjury and osmotic stress that impair oocyte quality and subsequent developmental competence in mammals. However, the complex molecular stress responses evoked by vitrification remain poorly understood. Here, we used sheep oocytes to compare metabolome and transcriptome profiles before and after vitrification. Integrated multi-omics revealed a significant accumulation of the osmoprotectant proline in vitrified oocytes. The upregulation of PYCR3, a regulator of proline synthesis, and the downregulation of P4HA1, which controls hydroxylation, collectively increased intracellular proline levels through this pathway. Guided by this finding, we supplemented the vitrification medium with 0.5 M L-proline, which significantly improved oocyte quality after warming.L-proline supplementation markedly increased the survival rates of vitrified oocytes, reduced oxidative stress, improved organelle distribution (spindle, endoplasmic reticulum, and mitochondria), decreased mitochondrial ROS levels, increased the mitochondrial membrane potential, mitigated ATP decline induced by cryopreservation, and maintained calcium homeostasis. These protective effects collectively enhanced the developmental competence of vitrified sheep oocytes.

Keywords: Sheep, oocyte, Vitrification, metabolic reprogramming, Proline

Received: 27 Sep 2025; Accepted: 24 Nov 2025.

Copyright: © 2025 Dilixiati, Zhao, Aihemaiti, Li, 樊, Zhao, Wusiman and Wang. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Xuguang Wang

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