Currently, clinical analysis of male infertility mainly relies on parameters of semen and sperm cells. However, the high diagnostic failure rates indicate that the current assessment methods are not sufficient and a new approach to evaluating sperm function still needs to be developed. Here we explored the feasibility of single-cell inductively coupled plasma mass spectrometry (sc-ICP-MS)-derived profiles to determine the elemental characteristics in viable capacitated sperm under normal and deficient conditions. To validate the measurements, we used male sterile Pmca4-knockout (KO) mice with impaired calcium clearance, known to be dysregulated due to loss of calcium efflux capacity during sperm capacitation. Consistently, we observed significantly increased calcium intensities in Pmca4-KO sperm upon capacitation stimulation compared with control sperm from the caudaepididymides of wild-type control (WT) mice. More importantly, we explored that the characteristic signatures of calcium intensities in individual spikes derived from sc-ICP-MS was consistent with the dynamics of relative calcium levels in single sperm reported in the literature. Prominent alterations were also observed in the dynamic signatures of sc-ICP-MS-derived profiles of essential elements, particularly the redox-labile elements including copper, iron, manganese, selenium, and zinc in Pmca4-KO sperm compared to WT controls. Therefore, our study demonstrates that elementomics of sc-ICP-MS-derived signals can reveal ionic dysregulation in plasma membrane Ca2+-ATPase isoform 4 protein deficient sperm, and that sc-ICP-MS assay can be applied for functional analysis of viable sperm in functional activities, such as capacitation stimulation. We propose that cell elementomics can be used as an alternative approach to assessing sperm quality and male fertility at the single-cell level.

中文翻译：

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获能期间正常和钙泵 PMCA4 缺陷的小鼠附睾精子中单细胞 ICP-MS 衍生信号的动态元素组学。

目前，男性不育症的临床分析主要依靠精液和精子细胞参数。然而，高诊断失败率表明当前的评估方法还不够，仍然需要开发评估精子功能的新方法。在这里，我们探讨了单细胞电感耦合等离子体质谱 (sc-ICP-MS) 衍生谱的可行性，以确定正常和缺陷条件下存活的获能精子的元素特征。为了验证测量结果，我们使用了钙清除受损的雄性不育 Pmca4 敲除 (KO) 小鼠，已知这种小鼠由于精子获能期间钙流出能力的丧失而失调。一致地，我们观察到与来自野生型对照（WT）小鼠尾附睾的对照精子相比，获能刺激后 Pmca4-KO 精子中的钙强度显着增加。更重要的是，我们探索了来自 sc-ICP-MS 的单个尖峰中钙强度的特征特征与文献中报道的单个精子中相对钙水平的动态一致。与 WT 对照相比，Pmca4-KO 精子中 sc-ICP-MS 衍生的必需元素谱的动态特征也观察到显着的变化，特别是氧化还原不稳定元素，包括铜、铁、锰、硒和锌。因此，我们的研究表明，sc-ICP-MS 衍生信号的元素组学可以揭示质膜 Ca2+-ATPase 亚型 4 蛋白缺陷精子中的离子失调，并且 sc-ICP-MS 测定可用于活精子的功能分析功能活动，例如获能刺激。我们建议细胞元素组学可以作为在单细胞水平评估精子质量和男性生育力的替代方法。