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Updated: Jun 17, 2025
Vitrification of In Vitro Matured Oocytes Collected from Adult and Prepubertal Ovaries in Sheep
Published on: July 10, 2021
Effects of vitrification on mitochondrial ultrastructure and membrane potential and its distribution in mouse oocytes
1Department of Reproductive Medicine, Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences), Southern Medical University, Guangzhou; College of Animal Science and Technology, Guangxi University, Nanning, China.
Background:
Vitrification is commonly used for in vitro fertilization and has significant impact on gametes.
Objective:
To investigate changes in ultrastructure, membrane potential and distribution of mitochondria in mouse oocytes after vitrification.
Materials And Methods:
Mouse oocytes were divided into three groups: one group as fresh control, one group for the toxicity test (treated with cryoprotectant but without vitrification), and the other for vitrification.
Results:
Most mitochondria in oocytes were damaged after cooling and warming, being rough and fuzzy in appearance, even swollen and broken. The membrane potential of the toxicity test group and the vitrification group was 0.320 +/-0.030 and 0.244 +/- 0.038, respectively, in comparison to the fresh group (0.398 +/- 0.043). The membrane potential of the vitrified oocytes was significantly lower than fresh oocytes and the toxicity test oocytes (P % 0.05), but there was no significant difference between fresh oocytes and the toxicity test oocytes (P > 0.05). Mitochondria in fresh oocytes were denser and strained stronger, with 59.5> distributed homogeneously and 36.4> polarized. The majority of mitochondria in the toxicity-tested oocytes were clustered (69.3>) and only a small portion were distributed homogeneously (19.6>), while mitochondria in vitrified oocytes were clustered (56.3>) and deficient (24.4>), and their fluorescent staining was weak and blurred. There was a significant disruption in mitochondrial function after vitrification.
Conclusion:
Vitrification alters the ultrastructure, membrane potential and distribution of mitochondria in oocytes, most likely caused by toxicity and mechanical injury. Doi.org/10.54680/fr24510110212.
