Abstract

This retrospective study assessed the biological intra-individual variability of the percentage of sperm with DNA damage (SDF) observed in subsequent ejaculates of the same individual. Variation in SDF was analyzed using the Mean Signed Difference (MSD) statistic based on 131 individuals, comprising 333 ejaculates. Either two, three or four ejaculates were collected from each individual. With this cohort of individuals two main questions were addressed; (1) does the number of ejaculates analyzed influence the variability in the level of SDF associated with each individual? and (2) is the variability observed in SDF similar when individuals are ranked according to their level of SDF? Results showed that the variation observed in mean SDF was not different when 2, 3 or 4 ejaculates were analyzed; consequently, we suggest that the assessment of SDF based on two ejaculates is likely to be representative of the mean SDF expected for the individual. In parallel, it was determined that the variation in SDF increased as SDF increased; in individuals presenting with an SDF value of lower than 30% (potentially fertile), only 5% possessed levels of MSD that could be considered as variable as that presented by individuals presenting with a recurrent high SDF. Finally, we showed that a single assessment of SDF in individuals with medium SDF (20-30%) was less likely to be predictive of the SDF value in the next ejaculate, and therefore, less informative of the patient’s SDF status.

摘要

这项回顾性研究评估了在同一个体随后的射精中观察到的具有 DNA 损伤 (SDF) 的精子百分比的生物学个体内变异性。使用基于 131 个人（包括 333 次射精）的平均符号差异 (MSD) 统计分析 SDF 的变化。从每个人身上收集了两份、三份或四份精液。对于这群人，解决了两个主要问题；(1) 分析的精液数量是否会影响与每个人相关的 SDF 水平的变异性？(2) 当个体根据他们的 SDF 水平排名时，在 SDF 中观察到的变异性是否相似？结果表明，当分析 2、3 或 4 次精液时，观察到的平均 SDF 的变化没有差异；最后，我们建议基于两次射精的 SDF 评估可能代表个人预期的平均 SDF。同时，确定 SDF 的变化随着 SDF 的增加而增加；在 SDF 值低于 30%（可能具有生育能力）的个体中，只有 5% 的 MSD 水平可以被视为与复发性高 SDF 个体所呈现的水平一样可变。最后，我们表明，对具有中等 SDF (20-30%) 的个体进行 SDF 的单一评估不太可能预测下一次射精的 SDF 值，因此，对患者 SDF 状态的信息较少。在 SDF 值低于 30%（可能具有生育能力）的个体中，只有 5% 的 MSD 水平可以被视为与复发性高 SDF 个体所呈现的水平一样可变。最后，我们表明，对具有中等 SDF (20-30%) 的个体进行 SDF 的单一评估不太可能预测下一次射精的 SDF 值，因此，对患者 SDF 状态的信息较少。在 SDF 值低于 30%（可能具有生育能力）的个体中，只有 5% 的 MSD 水平可以被视为与复发性高 SDF 个体所呈现的水平一样可变。最后，我们表明，对具有中等 SDF (20-30%) 的个体进行 SDF 的单一评估不太可能预测下一次射精的 SDF 值，因此，对患者 SDF 状态的信息较少。