Effects of Chlorogenic Acid on In Vitro Maturation and Vitrification Cryopreservation of Sheep Oocytes
College of Animal Science and Technology, Shihezi University, Shihezi 832003, China
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Authors to whom correspondence should be addressed.
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These authors contributed equally to this work.
Vet. Sci. 2025, 12(1), 62; https://doi.org/10.3390/vetsci12010062
Submission received: 6 November 2024
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Revised: 23 December 2024
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Accepted: 13 January 2025
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Published: 16 January 2025
(This article belongs to the Section Veterinary Reproduction and Obstetrics)
Simple Summary
Previous studies have shown that mitochondrial dysfunction, cytoplasmic abnormalities, and abnormal embryonic development are linked to excessive intracellular production of reactive oxygen species (ROS). Chlorogenic acid (CGA), a polyphenol widely found in plants, has been shown to have strong antioxidant properties by forming hydrogen radicals to eliminate the activity of free radicals such as hydroxyl radicals and superoxide anions. Thus, this study investigated the effects of CGA on oxidative stress and embryonic development of sheep oocytes by adding different CGA concentrations during in vitro maturation and vitrification freezing. The results showed that CGA effectively alleviates the oxidative stress damage of sheep oocytes, increases their maturation, cleavage, and blastocyst rates after solitary female activation, and promotes embryo development.
Abstract
Chlorogenic acid (CGA) has strong antioxidant properties. In order to improve the low maturation rate and poor vitrification freezing effect of sheep oocytes caused by oxidative stress. In this study, oocytes from 200 2–3-year-old Kazakh sheep were collected, and different concentrations of CGA were added to the maturation medium and vitrification freezing solution to study the effects of CGA on the maturation rate, cleavage rate, blastocyst rate, reactive oxygen species (ROS) and glutathione (GSH) levels, mitochondrial membrane potential, and the expression levels of oxidation and apoptosis-related genes in sheep oocytes. The results showed that adding 40 μmol/L CGA to the oocyte in vitro maturation solution significantly increased the maturation rate of oocytes, adding 50 μmol/L CGA to the vitrification cryopreservative solution significantly increased the cleavage and blastocyst rates of mature oocytes activated by parthenogenetic activation after freezing. During in vitro maturation and vitrification freezing in sheep oocytes, CGA significantly reduced the level of ROS and the expression of apoptosis-related genes (Caspase-3 and Bax/Bcl-2), and significantly increased the level of glutathione (GSH), mitochondrial membrane potential, and the expression of antioxidant and anti-apoptosis-related genes (SOD-2 and GPX-3). In addition, CGA significantly increased the expression of the anti-apoptotic gene (AKT) and anti-stress gene (FOXO) during vitrification freezing of sheep oocytes. In conclusion, 40 μmol/L CGA improves the maturation rate of sheep oocytes, and 50 μmol/L CGA improves the quality of parthenogenetic activation embryos after vitrification freezing of mature oocytes in sheep. These results provide a basis for the production of sheep in vitro embryos and the establishment of a germplasm resource bank.
Keywords:
sheep; oocyte; CGA; antioxidant
