This study sought to determine whether sperm irradiation using a light emission diode (LED) at 620-630 nm affects the motility, membrane integrity (viability), mitochondrial activity and intracellular levels of reactive oxygen species (ROS) in fresh diluted and liquid-stored donkey semen. With this purpose, sixteen ejaculates (eight fresh diluted and eight cooled-stored) were collected from eight adult jackasses. Fresh semen samples were diluted in Kenney extender and stimulated with red-light after collection, whereas cooled semen was stored at 4 °C for 24 h after dilution and then irradiated. In all cases, semen samples were packed into 0.5-mL transparent straws, which were then randomly divided into control and 19 treatments: six consisted of single red-light exposure, and the other 13 involved irradiation at light-dark-light intervals. Upon irradiation, sperm motility, membrane integrity mitochondrial membrane potential (MMP) and intracellular levels of superoxide anion (·O2-) and hydrogen peroxide (H2O2) were evaluated. While specific light-patterns increased both sperm motility and mitochondrial activity, they did not affect sperm membrane integrity and had no clear impact on intracellular ROS levels. The effects of irradiation patterns differed between fresh and cooled semen since, whereas 1 and 4 min patterns induced the greatest increments in the total and progressive motility of fresh semen, 4 min, 4-1-4 and 4-4-4 were the most suitable for cooled-stored samples. In both fresh diluted and cooled-stored semen, the motility increase observed after light-stimulation for 4 min was concomitant with changes in the percentages of spermatozoa with high mitochondrial membrane potential. In summary, this study shows, for the first time, that specific irradiation patterns increase sperm motility and mitochondrial activity in the donkey. Furthermore, the precise effect of red-light appears to depend on the specific functional status of cells, with separate effects on fresh and cooled samples.

中文翻译：

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红光照射对驴鲜液贮藏精液功能及成活的影响

本研究旨在确定使用 620-630 nm 的发光二极管 (LED) 照射精子是否会影响新鲜稀释和液体储存中的运动性、膜完整性（活力）、线粒体活性和细胞内活性氧 (ROS) 水平。驴精。为此，从 8 只成年公驴中收集了 16 份精液（8 份新鲜稀释的和 8 份冷藏保存的）。新鲜精液样品在 Kenney 稀释剂中稀释，收集后用红光刺激，而冷却的精液稀释后在 4°C 下储存 24 小时，然后进行照射。在所有情况下，将精液样本装入 0.5 mL 透明吸管中，然后将其随机分为对照组和 19 个处理：6 个由单次红光照射组成，另外 13 个涉及明暗光间隔照射。辐照后，评估了精子活力、膜完整性、线粒体膜电位 (MMP) 和细胞内超氧阴离子 (·O2-) 和过氧化氢 (H2O2) 的水平。虽然特定的光模式增加了精子活力和线粒体活性，但它们不影响精子膜的完整性，对细胞内 ROS 水平没有明显影响。新鲜精液和冷却精液的辐照模式的影响不同，因为 1 分钟和 4 分钟模式引起新鲜精液总运动性和渐进性运动的最大增量，4 分钟、4-1-4 和 4-4-4 是最多的适用于冷却储存的样品。在新鲜稀释和冷却储存的精液中，光刺激 4 分钟后观察到的运动性增加伴随着具有高线粒体膜电位的精子百分比的变化。总之，这项研究首次表明，特定的照射模式会增加驴的精子活力和线粒体活动。此外，红光的精确效果似乎取决于细胞的特定功能状态，对新鲜和冷却样品的影响不同。