SummaryAlthough bovine embryo in vitro production (IVP) is a common assisted reproductive technology, critical points warrant further study, including sperm traits and oxidative status of sperm for in vitro fertilization (IVF). Our aim was to evaluate whether the lipid peroxidation index of commercial bull semen is influenced by sperm traits and oxidative status of sperm populations selected using Percoll® gradient. Semen straws from 48 batches from 14 Nelore bulls were thawed individually, analyzed for motility and subjected to Percoll selection. After Percoll, the lipid peroxidation index of the extender was evaluated, whereas selected sperm were analyzed for motility, acrosome and membrane integrity, mitochondrial membrane potential, chromatin resistance and oxidative potential under IVF conditions. Batches were divided retrospectively in four groups according to lipid peroxidation index. Sperm from Group 4 with the lowest index of lipid peroxidation had, after Percoll selection, greater plasma membrane integrity (81.3%; P = 0.004), higher mitochondrial potential (81.1%; P = 0.009) and lower oxidative potential (135.3 ng thiobarbituric acid reactive substances (TBARS)/ml; P = 0.026) compared with Group 1 with highest lipid peroxidation index (74.3%, 73% and 213.1 ng TBARS/ml, respectively). Furthermore, we observed negative correlations for the lipid peroxidation index with motility, membrane integrity and mitochondrial potential, and positive correlations with oxidative potential. In conclusion, oxidative stress in semen straws, as determined using lipid peroxidation in the extender, is associated with sperm traits and their oxidative potential under IVF conditions. These results provided further insights regarding the importance of preventing oxidative stress during semen handling and cryopreservation, as this could affect sperm selected for IVF. Finally, Percoll selection did not completely remove sperm with oxidative markers.

中文翻译：

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公牛精液中的脂质过氧化影响 Percoll® 选择的精子的精子特征和氧化潜力

摘要虽然牛胚胎体外生产（IVP）是一种常见的辅助生殖技术，关键点值得进一步研究，包括精子特征和精子的氧化状态体外受精（IVF）。我们的目的是评估商业公牛精液的脂质过氧化指数是否受精子特征和使用 Percoll® 梯度选择的精子群体的氧化状态的影响。将来自 14 头 Nelore 公牛的 48 批精液单独解冻，分析运动性并进行 Percoll 选择。在 Percoll 之后，评估了扩展剂的脂质过氧化指数，而在 IVF 条件下分析了所选精子的运动性、顶体和膜完整性、线粒体膜电位、染色质抗性和氧化电位。根据脂质过氧化指数将批次回顾性分为四组。脂质过氧化指数最低的第 4 组精子在选择 Percoll 后具有更高的质膜完整性（81.3%；磷= 0.004), 更高的线粒体电位 (81.1%;磷= 0.009) 和较低的氧化电位 (135.3 ng 硫代巴比妥酸反应物质 (TBARS)/ml；磷= 0.026）与脂质过氧化指数最高的第 1 组相比（分别为 74.3%、73% 和 213.1 ng TBARS/ml）。此外，我们观察到脂质过氧化指数与运动性、膜完整性和线粒体电位呈负相关，与氧化电位呈正相关。总之，精液中的氧化应激，如在稀释剂中使用脂质过氧化测定的那样，与精子特征及其在体外受精条件下的氧化潜力有关。这些结果提供了关于在精液处理和冷冻保存期间防止氧化应激的重要性的进一步见解，因为这可能会影响为 IVF 选择的精子。最后，Percoll 选择并没有完全去除带有氧化标记的精子。