Chronic environmental exposure to lead affects semen quality in a Mexican men population

Background: Male infertility is affected by several factors. Lead is one of the heavy metals more bioavailable than usually modifies the sperm quality in humans. Objective: The aim of this study was to establish the role of lead in semen quality in environmentally exposed men. Materials and Methods: Semen and blood samples were obtained from two groups: the exposed group (EG=20) and the non-exposed group (NEG=27). Two semen aliquots were used, one to evaluate spermatic quality and the other for lead determination. Blood (PbB) and semen lead (PbS) determination was performed by atomic absorption spectrophotometry. Results: The PbB concentration was significantly greater in the EG, 10.10±0.97 µgdL-1 than in the NEG, 6.42±0.38 µgdL-1 (p<0.01), as well as the PbS concentration, with 3.28±0.35 and 1.76±0.14µgdL-1 in the EG and NEG respectively (p=0.043). A significant correlation between PbS and PbB concentration in the EG was found (r=0.573, p=0.038). Overall, the spermatic quality was lower in the EG than in the NEG. Specifically, there were significant differences in the spermatic concentration [EG=43.98±6.26 and NEG=68.78±8.51X10(6) cellmL-1 (p<0.01)], motility [EG=49±7 and NEG=67±4% (p=0.029)], viability [EG=36.32±3.59 and NEG=72.12±1.91% (p<0.01)] and abnormal morphology [EG=67±18 and NEG=32±12% (p<0.01)]. In the immature germ cells (IGC) concentration differences were found only for A cells (EG=8.1±1.1x100 and NEG=3.2±1.9X100 spermatozoa) (p<0.01) and for Sab cells (EG=3.4±2.2x100 and NEG=1.1±1.0X100 spermatozoa) (p=0.041). Conclusion: These results suggest that chronic environmental exposure to low levels of lead adversely affect the spermatic quality.