The Relationship Between Atmospheric Particulates Exposure And Male Semen Quality

Air pollution has become one of the main factors threatening human health,which is closely related to the occurrence of respiratory system diseases,cardiovascular system diseases and reproductive system diseases.The World Health Organization(WHO)reported that about 80%urban residents live in areas where air quality does not meet WHO air quality standards.China,which is in the stage of rapid socio-economic development,is facing serious air pollution.As one of the areas with the fastest urbanization process and the strongest economic strength,the air pollution in the Yangtze River Delta,especially the particle pollution,deserves attention.Research shows that about 10%of couples in the world have fertility problems,while male infertility accounts for about 50%of the causes of infertility.In the past 70years,there has been a significant decline in the quality of men's semen,even in the normal fertile population.The factors that lead to semen quality decline include exposure to air pollutants,environmental endocrine disruptors and heavy metals.However,PM_2.5(aerodynamic diameter?2.5?m)and PM₁₀(aerodynamic diameter?10?m)are typical pollutants in the air,and the research on the impact of PM_2.5 and PM₁₀ on male reproductive health is also increasing.Population studies found that after exposure to air pollution,the semen quality of men decreased significantly,such as substantial decline in the number of normal sperm and decrease in sperm density and sperm viability.It was found in animal studies that PM_2.5 exposure can affect spermatogenesis and sperm maturation of mice,and then damage the fertility of male mice.These results provide strong evidence for the reduction of semen quality caused by atmospheric particulate matter.In order to evaluate the effect of atmospheric particulates on the quality of male spermatozoa,we systematically reviewed 17literatures published by December 2019.The systematic review found that the correlation results between atmospheric particles and semen quality in each study were inconsistent,in addition,there was no comparability among the studies.Standardized air pollution and semen quality assessment methods need to be used for research to reach more reliable conclusions.It takes about three months for sperm to mature from production.It has been confirmed that there are three key stages of sperm development:the epididymis storage stage is 0-9 days before semen quality inspection,the sperm vitality development stage is 10-14 days before semen quality inspection,and the spermatogenesis stage is 70-90days before semen quality inspection.The average exposure level of particulate matter90 days before semen examination can be used to study whether there is a relationship between atmospheric particulate matter and semen quality,but it can't explain which stage of spermatogenesis will be affected by atmospheric particulate matter.Therefore,the purpose of this study is to explore the effect of PM_2.5 and PM₁₀exposure on the semen quality of men in Huai'an City 90 days before semen detection and every 15 days through retrospective cohort study,and to clarify which stage of sperm development is most vulnerable to the impact of atmospheric particles,so as to provide theoretical basis and data support for the correlation assessment of atmospheric particles and men's semen quality.Part?:Particulate matter and male semen quality in men:a systematic reviewObjectiveParticulate matter pollution is associated with a range of adverse health outcomes,including reproductive toxicity,but its impact on semen quality in men is still unclear.In this part,the method of systematic review is proposed to systematically summarize and integrate the original research results,so as to provide more complete,reliable and authoritative evidence for clarifying the relationship between atmospheric particles and semen quality.MethodsWe conducted a systematic review(as of December 2019)to assess the impact of atmospheric particulates on sperm quality.We included 17 studies to assess the effects of particles with different aerodynamic diameters(e.g.,PM_2.5,PM₁₀)on sperm count,sperm density,total sperm activity,percentage of forward motile sperm,sperm morphology,and DNA fragmentation.We rated 17 studies using the NOS scale and summarized the exposure assessment methods.ResultsConsidering these factors and the number of studies that found important results(positive or negative),there is no conclusion that particulate matter exposure can reduce the total number or concentration of sperm,there is limited evidence of adverse effects on sperm viability,and there is more evidence of the impact on the decline of percentage of normal morphology sperm.There are few literatures focusing on DNA fragmentation,but there is a negative correlation trend.ConclusionIn summary,most studies have concluded that exposure to atmospheric particulates affects at least one aspect of semen quality.However,the results are inconsistent,and there is no comparability among the studies.Standardized air pollution and semen measures need to be used for research to reach more reliable conclusions.Part ?: The relationship between particulate matter exposure and male semen quality in Huai'an,ChinaObjective The purpose of this study was to analyze the relationship between PM exposure and semen quality in Huai'an area,and to explore the key time window of its exposure effect.Methods The study included 1955 men with 2073 semen samples between 2016 and 2017 with moderate to high exposure to air pollution in Huai'an,China.Three multivariable linear regression models were used to conduct dose-effect analyses for particulate matter exposure and semen quality and to estimate the influence during different exposure periods by every 15 days period before ejaculation in all participants group and normal semen quality participants group.Results The average age of the observations was 28.9 years old and the average abstinence period was 4.2days.The results showed high correlations between both PM2.5 and PM10 exposures throughout entire spermatogenesis and the declines of sperm count(? =-0.93,P <2×10-16 and ? =-1.00,P < 2×10-16),and sperm concentration(? =-1.00,P < 2×10-16 and ? =-1.06,P < 2×10-16),and PM10 exposure decreased sperm total motility(? =-0.60,P = 2.56×10-7),but not sperm progressive motility.Furthermore,PM2.5 exposure decreased sperm count and concentration during 15-75 lag days,and PM10 exposure showed significant association with sperm count and concentration during 0-75 lag days.PM2.5 and PM10 exposures during 45-59 lag days were both inversely associated with sperm total motility(all P value < 0.05).Conclusion In the whole process of spermatogenesis,especially in the early and middle stage,the exposure of environmental particles was negatively correlated with semen quality,sperm count and sperm concentration,especially sperm concentration.