Effect of PM10 on Human Spermatozoa: An In Vitro Study

This study was aimed at evaluating the in vitro effects of particulate matter (ranging from 2.5-10 m in an aerodynamic diameter, PM10) from an urban area on the motility of human spermatozoa. Samples of swim up selected human spermatozoa from three healthy men with normal semen parameters, according to WHO guidelines, were incubated for 4 hours with 10, 50 and 75 μg/ml of PM10. Kinetic parameters were evaluated with Computer-Assisted Sperm Analysis (CASA) and the presence of apoptosis and necrosis was assessed by AnnexinV/Propidium iodide assay. Data was statistically elaborated. Incubation of sperm with 10 g/ml PM10 for 4 hours did not affect sperm motility. On the contrary, a decrease in progressive motility was evident at 50 g/ml and 75 g/ml PM10. Among the kinetic parameters assessed with CASA system, the linearity variable was significantly lower in sperm treated with 50 g/ml and 75 g/ml PM10 vs controls (P<0.0001) and the amplitude of the lateral head displacement variable was significantly higher in sperm treated with 50 g/ml vs controls (P=0.0211). A substantial increase in necrosis, in up to 30% of sperm, was evident only in samples treated with 75 g/ml PM10. In conclusion, this preliminary study could indicate that PM10 is not potentially harmful to spermatozoa in vitro, except above a very high threshold (50-75 μg/ml) that is difficult to reach in vivo and that motility and viability are only partially affected.