Key Laboratory of Environment and Health, Ministry of Education & Ministry of Environmental Protection, And State Key Laboratory of Environmental Health (incubating), School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China; Department of Occupational and Environmental Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, PR China.
Department of Epidemiology, School of Public Health, Southern Medical University, Guangzhou, PR China.
Environ Res. 2023 Jan 1;216(Pt 4):114737. doi: 10.1016/j.envres.2022.114737. Epub 2022 Nov 11.
In animal and human studies, exposure to trihalomethanes (THMs) has been associated with reduced semen quality. However, the underlying mechanisms remain poorly understood.
To investigate the associations of blood THM concentrations with sperm mitochondrial DNA copy number (mtDNAcn) and telomere length (TL) among healthy men.
We recruited 958 men who volunteered as potential sperm donors. A single blood sample was collected from each participant at recruitment and measured for chloroform (TCM), bromodichloromethane (BDCM), dibromochloromethane (DBCM), and bromoform (TBM) concentrations. Within a 90-day follow-up, the last semen sample provided by each participant was quantified for sperm mtDNAcn and TL. We used multivariable linear regression models to assess the associations between blood THM concentrations and sperm mtDNAcn and TL. We also performed stratified analyses according to the time intervals between baseline blood THM determinations and semen collection (i.e., 0-9, 10-14, 15-69, or >69 days) to explore potential windows of susceptibility.
After adjusting for potential confounders, we found inverse associations between quartiles (or categories) of blood TBM, brominated THM (Br-THM, the sum of BDCM, DBCM, and TBM), and total THM (TTHM, the sum of all four THMs) concentrations and sperm mtDNAcn (all P for trend≤0.03). Besides, we found inverse associations between quartiles of blood TCM, Br-THM, chlorinated THM (Cl-THM, the sum of TCM, BDCM, and DBCM), and TTHM concentrations and sperm TL (all P for trend<0.10). Stratified analyses showed stronger associations between Br-THM concentrations and sperm mtDNAcn determined 15-69 days since baseline exposure determinations, and between blood TCM and TTHM concentrations and sperm TL determined >69 days since baseline exposure determinations.
Exposure to THMs may be associated with sperm mitochondrial and telomeric dysfunction.
在动物和人体研究中，三卤甲烷（THMs）暴露与精液质量下降有关。然而，其潜在机制仍知之甚少。
探讨健康男性血液中 THM 浓度与精子线粒体 DNA 拷贝数（mtDNAcn）和端粒长度（TL）的关系。
我们招募了 958 名自愿作为潜在精子供体的男性。每位参与者在招募时采集一份血样，检测氯仿（TCM）、溴二氯甲烷（BDCM）、二溴氯甲烷（DBCM）和溴仿（TBM）浓度。在 90 天的随访中，每位参与者提供的最后一份精液样本用于定量分析精子 mtDNAcn 和 TL。我们使用多变量线性回归模型来评估血液 THM 浓度与精子 mtDNAcn 和 TL 之间的关系。我们还根据基线血液 THM 测定与精液采集之间的时间间隔（即 0-9、10-14、15-69 或>69 天）进行分层分析，以探索潜在的易感窗口。
在调整了潜在混杂因素后，我们发现血液 TBM、溴化 THM（Br-THM，BDCM、DBCM 和 TBM 的总和）和总 THM（TTHM，所有四种 THMs 的总和）浓度的四分位数（或类别）与精子 mtDNAcn 呈负相关（所有趋势 P 值≤0.03）。此外，我们发现血液 TCM、Br-THM、氯化 THM（Cl-THM，TCM、BDCM 和 DBCM 的总和）和 TTHM 浓度的四分位数与精子 TL 呈负相关（所有趋势 P 值<0.10）。分层分析显示，Br-THM 浓度与暴露基线后 15-69 天测定的精子 mtDNAcn 之间的相关性更强，而血液 TCM 和 TTHM 浓度与暴露基线后>69 天测定的精子 TL 之间的相关性更强。
THM 暴露可能与精子线粒体和端粒功能障碍有关。
