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 pivot role in maintaining sperm viability. However, the role of seminal plasma in air pollution related sperm quality decline remain underestimated. 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 in semen samples. The six main air pollutants (PM, PM, NO, SO, CO, O) 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-response associations. And we found that PM exposures were negatively related with sperm total motility and the exposures of PM and PM were inversely associated with sperm progressive motility during epididymal stage. Furthermore, PM and PM exposures were positively associated with seminal plasma MDA and PM was negatively related to seminal plasma T-AOC during epididymal stage. PM, PM and CO exposures during total sperm cycle period might relate to increased seminal plasma testosterone. Mediation analysis indicated seminal plasma MDA and T-AOC partly mediated PM 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 sperm motility decline.