Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0HS, UK.
Department of Urology, Charing Cross Hospital, Imperial College NHS Trust, London W6 8RF, UK.
Medicina (Kaunas). 2023 Dec 22;60(1):25. doi: 10.3390/medicina60010025.
Mean sperm counts are declining at an accelerated rate and infertility is increasingly becoming a public health concern. It is now understood that human semen, previously considered to be sterile, harbours its own specific microbiome. Via activated leucocytes and the generation of reactive oxygen species, bacteria have the capability of evoking an immune response which may lead to sperm damage. Men with infertility have higher rates of both reactive oxygen species and sperm DNA damage. Due to the lack of sensitivity of routine culture and PCR-based methods, next-generation sequencing technology is being employed to characterise the seminal microbiome. There is a mounting body of studies that share a number of similarities but also a great range of conflicting findings. A lack of stringent decontamination procedures, small sample sizes and heterogeneity in other aspects of methodology makes it difficult to draw firm conclusions from these studies. However, various themes have emerged and evidence of highly conserved clusters of common bacteria can be seen. Depletion or over-representation of specific bacteria may be associated with aberrations in traditional and functional seminal parameters. Currently, the evidence is too limited to inform clinical practice and larger studies are needed.
精子浓度呈加速下降趋势，不育问题日益成为公共卫生关注的焦点。人们现在认识到，曾被认为是无菌的人类精液中存在着特定的微生物组。通过激活白细胞和产生活性氧物质，细菌有能力引发免疫反应，从而导致精子损伤。不育男性的活性氧物质和精子 DNA 损伤率都更高。由于常规培养和基于 PCR 的方法的敏感性不足，下一代测序技术正被用于描述精液微生物组。越来越多的研究有许多相似之处，但也有很大的冲突发现。由于缺乏严格的消毒程序、样本量小以及方法学的其他方面存在异质性，很难从这些研究中得出确凿的结论。然而，已经出现了各种主题，并且可以看到高度保守的常见细菌群集的证据。特定细菌的耗竭或过度表达可能与传统和功能精液参数的异常有关。目前，证据还不足以指导临床实践，需要进行更大规模的研究。
