El-Sanea Amro M, Abdoon Ahmed Sabry S, Kandil Omaima M, El-Toukhy Nahed E, El-Maaty Amal M Abo, Ahmed Hodallah H
Department of Animal Reproduction and Artificial Insemination, Veterinary Research Division, National Research Centre, Tahrir St., Dokki 12622, Cairo, Egypt.
Department of Animal Physiology, Faculty of Veterinary Medicine, Cairo University, Giza Square 12211, Cairo, Egypt.
Vet World. 2021 Jan;14(1):78-84. doi: 10.14202/vetworld.2021.78-84. Epub 2021 Jan 11.
Oxidative stress (OS) is one of the major disruptors of oocyte developmental competence, which appears due to the imbalance between the production and neutralization of reactive oxygen species (ROS).
In Experiment 1, buffalo oocytes were matured, fertilized, and cultured at 38.5°C under 5% CO + 20% O in standard CO incubator (OS) or under 5% O + 5% CO + 90% N (Multi-gas incubator, low O). In Experiment 2, buffalo cumulus oocytes complexes (COCs) were matured in Basic maturation medium (BMM) composed of TCM199+ 10% FCS+ 10 µg/ml FSH+ 50 µg/ml gentamicin (control group) or in BMM supplemented with 50 μM ascorbic acid (ascorbic acid group) or 3.0 mM glutathione (glutathione group) or 10 M melatonin (melatonin group) and cultured at 38.5°C under 20% O for 24 h. Matured buffalo oocytes in control, ascorbic acid, or melatonin groups were fertilized and zygotes were cultured for 8 days under the same conditions.
In both experiments, maturation, cleavage, and blastocyst rates were recorded. Results showed that culture of buffalo oocytes under low O (5% O) significantly increased maturation, cleavage, and blastocyst rates (p<0.05). Meanwhile, under 20% O, addition of 10 M melatonin or 50 μM ascorbic acid to maturation (IVM) medium significantly improved cumulus cell expansion, nuclear maturation rates of buffalo oocytes (p<0.05), and increased cleavage and blastocyst rates (p<0.05).
About 5% O is the optimum condition for production of buffalo embryos, and addition of 10 M melatonin to IVM medium for oocytes cultured under 20% O could alleviate the adverse effect of high oxygen tension and increased embryo yield.
氧化应激（OS）是卵母细胞发育能力的主要破坏因素之一，其由于活性氧（ROS）产生与中和之间的失衡而出现。
在实验1中，水牛卵母细胞在标准CO培养箱（OS）中于38.5°C、5% CO₂ + 20% O₂条件下成熟、受精并培养，或在5% O₂ + 5% CO₂ + 90% N₂（多气培养箱，低氧）条件下进行。在实验2中，水牛卵丘卵母细胞复合体（COCs）在由TCM199 + 10% FCS + 10 μg/ml FSH + 50 μg/ml庆大霉素组成的基础成熟培养基（BMM）中成熟（对照组），或在添加了50 μM抗坏血酸的BMM（抗坏血酸组）、3.0 mM谷胱甘肽的BMM（谷胱甘肽组）或10 μM褪黑素的BMM（褪黑素组）中于38.5°C、20% O₂条件下培养24小时。对照组、抗坏血酸组或褪黑素组的成熟水牛卵母细胞进行受精，受精卵在相同条件下培养8天。
在两个实验中，均记录了成熟率、裂解率和囊胚率。结果显示，在低氧（5% O₂）条件下培养水牛卵母细胞显著提高了成熟率、裂解率和囊胚率（p<0.05）。同时，在20% O₂条件下，向成熟（IVM）培养基中添加10 μM褪黑素或50 μM抗坏血酸可显著改善水牛卵母细胞的卵丘细胞扩展、核成熟率（p<0.05），并提高裂解率和囊胚率（p<0.05）。
约5% O₂是水牛胚胎生产的最佳条件，对于在20% O₂条件下培养的卵母细胞，向IVM培养基中添加10 μM褪黑素可减轻高氧张力的不利影响并提高胚胎产量。
