State Key Laboratory of Reproductive Medicine, Institute of Toxicology, Nanjing Medical University, Nanjing, China; Key Laboratory of Modern Toxicology of Ministry of Education, School of Public Health, Nanjing Medical University, Nanjing, China.
Department of Obstetrics, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing, China.
Environ Pollut. 2022 May 1;300:118994. doi: 10.1016/j.envpol.2022.118994. Epub 2022 Feb 12.
Some studies have examined the association between air pollution and semen quality. While it is less of evidence on the sperm quality after long-term air pollution exposure, especially the co-exposure of different air pollution components. Additionally, the role of DNA methylation in it hasn't been confirmed. This study aimed to investigate whether long-term exposure to air pollution was associated with semen quality, as well as to explore the effect of sperm DNA methylation in such association. From 2014 to 2016, 1607 fertile men were enrolled to evaluate 14 parameters of semen quality. Exposure window was defined as one-year before semen sampling. Multivariable linear regression and weighted quantile sum (WQS) regression model were used to investigate the association between six air pollutants co-exposure and semen quality. Sensitivity analysis regarding at the normal semen quality group was also conducted. Semen samples were randomly selected from 200 participants to detect the genomic 5-methylcytosine (5 mC) and 5-hydroxymethylcytosine (5-hmC) levels in sperm. In the total population, PM, PM, SO, and NO were negatively associated with sperm total motility (PM: β = -2.67, P = 0.009; PM: β = -2.86, P = 0.004; SO: β = -2.32, P = 0.011; NO: β = -2.21, P = 0.012). Results of the normal semen quality group were consistent with those from the whole population. WQS regression results indicated significant decreasing sperm total motility after the co-exposure of the six air pollutants (β = -1.64, P = 0.003) in whole participants. Wherein, PM accounted for largest proportion (43.4%). The 5-hmC level was positively associated with PM exposure (β = 0.002, P < 0.001). Long-term exposure to PM, PM, SO, and NO, as well as co-exposure to six air pollutants, reduced semen quality in fertile men. As the most significant contributor of air pollutant, PM exposure decreased sperm DNA methylation.
一些研究已经探讨了空气污染与精液质量之间的关系。然而，对于长期暴露于空气污染后精子质量的影响，特别是不同空气污染物成分的共同暴露，证据还较少。此外，DNA 甲基化在其中的作用尚未得到证实。本研究旨在探讨长期暴露于空气污染是否与精液质量有关，并探索精子 DNA 甲基化在这种关联中的作用。2014 年至 2016 年，共招募了 1607 名生育能力正常的男性，以评估 14 项精液质量参数。暴露窗口定义为精液采样前一年。多变量线性回归和加权分位数总和（WQS）回归模型用于研究六种空气污染物共同暴露与精液质量之间的关系。还对正常精液质量组进行了敏感性分析。随机从 200 名参与者中抽取精液样本，检测精子中基因组 5-甲基胞嘧啶（5mC）和 5-羟甲基胞嘧啶（5-hmC）的水平。在总人群中，PM、PM、SO 和 NO 与精子总活力呈负相关（PM：β=-2.67，P=0.009；PM：β=-2.86，P=0.004；SO：β=-2.32，P=0.011；NO：β=-2.21，P=0.012）。正常精液质量组的结果与全人群的结果一致。WQS 回归结果表明，在所有参与者中，六种空气污染物共同暴露后精子总活力显著下降（β=-1.64，P=0.003）。其中，PM 占比最大（43.4%）。5-hmC 水平与 PM 暴露呈正相关（β=0.002，P<0.001）。长期暴露于 PM、PM、SO 和 NO，以及六种空气污染物的共同暴露，降低了生育能力正常男性的精液质量。PM 暴露作为空气污染物的最主要贡献者，降低了精子 DNA 甲基化水平。
