Environmental car exhaust pollution damages human sperm chromatin and DNA

The adverse role of traffic pollutants on male fertility is well known. Aim of this study was to evaluate their effects on sperm chromatin/DNA integrity. Methods: To accomplish this, 36 men working at motorway tollgates and 32 unexposed healthy men (controls) were enrolled. All of them were interviewed about their lifestyle. Hormone, semen samples and environmental and biological markers of pollution were evaluated. Sperm chromatin and DNA integrity were evaluated by flow cytometry following propidium iodide staining and TUNEL assay, respectively. Results: LH, FSH and testosterone serum levels were within the normal range in tollgate workers. Sperm concentration, total sperm count, total and progressive motility, and normal forms were significantly lower in these men compared to controls. Motorway tollgate workers had a significantly higher percentage of spermatozoa with damaged chromatin and DNA fragmentation, a late sign of apoptosis, compared to controls. A significant direct correlation was found between spermatozoa with damaged chromatin or fragmented DNA and the length of occupational exposure, suggesting a timedependent relationship. Conclusion: This study showed that car exhaust exposure has a sperm genotoxic effect on human spermatozoa. This may be of relevant importance not only for the reproductive performance of the men exposed, but also for the offspring health