Environmental exposure to zinc and copper influences sperm quality in fertile males

The presented study was designed to investigate the associations between environmental exposure to zinc and copper and levels of the parameters of oxidative stress and antioxidant defence system and selected cytokines in the seminal plasma of fertile males.

The study population consisted of 65 fertile male volunteers from the southern region of Poland. Based on the medians of the levels of copper and zinc in seminal plasma, the study subjects were divided into 4 subgroups: groups with low and high environmental exposure to copper (Cu-L and Cu-H), groups with low and high environmental exposure to zinc (Zn-L and Zn-H).

Semen volume, pH, count, motility and morphology of sperm cells in the Cu-L and Cu-H groups did not differ significantly. In the Cu-H group, TOS was increased significantly by 243% when compared to the Cu-L group. Similarly, median of IL-10 level in the Cu-H group was increased by 144% compared to the Cu-L group. Spearman correlation showed positive correlations between the levels of copper and TOS and IL-10. Negative correlations between copper and G-CSF and GM-CSF were also shown. In the Zn-L group, the percentage of progressively motile sperm cells after 1 hour was significantly higher by 17%, compared to the Zn-L group. In the Zn-H group, levels of G-CSF and MCP-1 were significantly higher by 70% and 145%, respectively, compared to the Zn-L group. The level of IL-10 was significantly lower in the Zn-H group by 60%, compared to the Zn-L group. Spearman correlation indicated that there is a positive correlation between the level of zinc and thiol groups, G-CSF and GM-CSF. Negative correlations between zinc and TOS and IL-10 were also shown.

Zinc enhances motility in fertile men. This beneficial effect of zinc may be due to zinc-induced reduction in the plasma oxidative stress intensity and modulations of the immune response. This study confirms the antagonistic relationship between zinc and copper.