The role of total antioxidant capacity and malondialdehyde of seminal plasma in the association between air pollution and sperm quality

Accumulating evidence has suggested that men exposed to air pollution are associated with decreased sperm quality, and seminal plasma plays a pivotal role in maintaining sperm viability. However, the role of seminal plasma in air pollution related sperm quality decline remain unestablished. In current study, we recruited 524 participants from couples who underwent in vitro fertilization treatment due to female factors at a fertility clinic in China from March to August 2020. Conventional sperm parameters, total antioxidant capacity (T-AOC), malondialdehyde (MDA) and testosterone were measured using semen samples. The six main air pollutants (PM2.5, PM10, NO2, SO2, CO, O-3) during four key periods of sperm development (meiotic stage, spermiogenesis stage, epididymal stage and total sperm cycle period) were estimated using inverse distance weighting method. Multiple linear regression models were employed to investigate the exposure-outcome relationships. And we found that PM10 exposures were negatively related to sperm total motility and the exposures of PM2.5 and PM10 were inversely associated with sperm progressive motility during epididymal stage. Furthermore, PM2.5 and PM10 exposures were positively associated with seminal plasma MDA and PM10 was negatively related to seminal plasma T-AOC during epididymal stage. PM2.5, PM10 and CO exposures during total sperm cycle period might relate to increased seminal plasma testosterone. Mediation analysis indicated seminal plasma MDA and T-AOC partially mediated PM10 associated reduction of sperm motility during epididymal stage. Our study suggested MDA and T-AOC of seminal plasma played a role in air pollution associated decline of sperm motility.

Automated summary

Accumulating evidence suggests that exposure to air pollution is associated with decreased sperm quality in men, and seminal plasma plays a vital role in maintaining sperm viability. However, the role of seminal plasma in air pollution-induced decline in sperm quality remains unclear. In this study, 524 participants were recruited from couples undergoing in vitro fertilization treatment in China, and various sperm parameters and air pollutant exposures were measured. The results showed that PM10 exposure was negatively associated with sperm motility, and PM2.5 and PM10 exposures were inversely related to sperm progressive motility during the epididymal stage. Additionally, PM2.5 and PM10 exposures were positively associated with seminal plasma MDA and negatively associated with seminal plasma T-AOC during the epididymal stage. Moreover, PM2.5, PM10, and CO exposures during the total sperm cycle period may be related to increased seminal plasma testosterone. Mediation analysis indicated that seminal plasma MDA and T-AOC partially mediated the negative effect of PM10 on sperm motility during the epididymal stage. Overall, this study suggests that MDA and T-AOC in seminal plasma play a role in the air pollution-associated decline in sperm motility.