Heavy metals, biomarkers of oxidative stress and changes in sperm function: A case-control study

Heavy metal-induced oxidative stress has been implicated in abnormal sperm functions and male infertility. Serum and seminal levels of heavy metals and biomarkers of oxidative stress were compared in fertile and infertile men. A total of 130 men aged 20–60 yr comprising 30 azoospermic, 50 oligozoospermic, and 50 normozoospermic men were studied. Semen analysis was done by world health organization guidelines, biomarkers of oxidative stress (total antioxidant capacity (TAC), total plasma peroxidase (TPP), oxidative stress index (OSI), vitamin C (vit C and nitric oxide (NO)) and fructose by colorimetry and serum and seminal heavy metals (zinc (Zn), selenium (Se), cadmium (Cd) and lead (Pb)) by atomic absorption spectrophotometry. Azoospermic and oligozoospermic men had higher serum and seminal peroxides (TPP, p= 0.00), higher serum heavy metals (Zn, Se, Pb, and Cd (p= 0.01)) and lower sperm concentration, %motility, serum and seminal antioxidants (vit C, TAC, NO, GSH (p= 0.01)) compared to normozoospermic men. Higher seminal peroxides (TPP, p= 0.001), heavy metals (Pb and Cd (p= 0.03)) and lower sperm concentration, %motility, and seminal antioxidants (TAC and NO (p= 0.00)) were also observed in azoospermic men compared to oligozoospermic men. Negative correlations were observed between seminal fructose and seminal vit C (r= -0.535, p= 0.015), GSH (r= -0.734, p= 0.000), NO (r= -0.714, p= 0.000), Zn (r= -0.774, p= 0.000) and Se (r= -0.719, p=
0.000) only in azoospermic men. Elevated heavy metal levels, increased lipid peroxidation and antioxidant depletion is associated with abnormal sperm functions in men studied.