We previously reported that the administration of d-aspartate (D-Asp) in drinking water over a 2-4-week period to 7-week-old mice resulted in higher sperm quality and increased in vitro fertilisation (IVF) rates associated with a systemic increase of luteinizing hormone and testosterone levels in the serum. The goal of this study was to investigate the effects of in vitro treatment with D-Asp on the IVF rate, embryo transfer, and sperm parameters of cryopreserved-thawed C57BL/6NTacCnrm (B6N) spermatozoa derived from young and adult mice. In this study, cryopreserved-thawed B6N spermatozoa from males aging 9, 11, 13, and 16 weeks were treated for 1 h with 4 mM D-Asp during capacitation. Thereafter, the in vitro fertilisation ability and the embryo transfer efficiency were analysed. Also, the kinetic activity of the treated spermatozoa and the acrosome reaction were measured after 1 h, 2 h, and 5 h of incubation. The capacitation rate of spermatozoa was determined after 1 h of pre-incubation. Spermatozoa from 9- and 11-week-old mice, which were treated with D-Asp, led to significantly increased IVF rates. However, spermatozoa derived from 13- and 16-week-old mice did not lead to a significant improvement in the fertilisation rate. At all ages examined, no differences were observed in the birth rate and sperm kinetic parameters. After 1 h incubation under the same conditions as the IVF was performed, the capacitation rate and the acrosome reaction were significantly higher with the D-Asp-treated spermatozoa from 9-week-old (67.5% vs. 41% and 14.5% vs. 10.5%, respectively) and 11-week-old mice (78.5% vs. 41.1% and 21.0% vs. 3.8%, respectively), corresponding to the improved IVF results. Therefore, the present results demonstrate, for the first time, a direct role of D-Asp in the capacitation process and acrosome reaction.

中文翻译：

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d-天冬氨酸体外治疗提高了年轻 B6N 小鼠的精子生育能力

我们之前曾报道过，在 2-4 周的时间内，在饮用水中对 7 周龄小鼠施用 d-天冬氨酸 (D-Asp) 可导致更高的精子质量和增加的体外受精 (IVF) 率。血清中促黄体生成素和睾酮水平的全身性增加。本研究的目的是研究 D-Asp 体外处理对来自年轻和成年小鼠的冻融 C57BL/6NTacCnrm (B6N) 精子的体外受精率、胚胎移植和精子参数的影响。在这项研究中，在获能期间用 4 mM D-Asp 处理来自 9、11、13 和 16 周龄男性的冷冻解冻 B6N 精子 1 小时。此后，分析了体外受精能力和胚胎移植效率。还，在孵育 1 小时、2 小时和 5 小时后测量处理过的精子的动力学活性和顶体反应。预孵育 1 小时后测定精子获能率。用 D-Asp 处理的 9 周龄和 11 周龄小鼠的精子导致试管婴儿率显着增加。然而，来自 13 周龄和 16 周龄小鼠的精子并未显着提高受精率。在检查的所有年龄段，出生率和精子动力学参数均未观察到差异。在与 IVF 相同的条件下孵育 1 小时后，经 D-Asp 处理的 9 周龄精子的获能率和顶体反应显着更高（67.5% vs. 41% 和 14.5% vs.分别为 10.5%）和 11 周龄小鼠（78.5% 对 41.1% 和 21.0% 对 3.8%，分别），对应于改进的试管婴儿结果。因此，目前的结果首次证明了 D-Asp 在获能过程和顶体反应中的直接作用。