Evaluation of the NOX5 protein expression and oxidative stress in sperm from asthenozoospermic men compared to normozoospermic men

Purpose NADPH oxidase 5 (NOX5), the main isoform of NOX in spermatozoa, has been recognized as the main active generators of reactive oxygen species (ROS), including superoxide anion (O-2(-center dot)) and hydrogen peroxide (H2O2). ROS have been shown to play important roles in many physiological and pathological conditions in spermatozoa. The present study aims to investigate the alterations of NOX5 protein expression and oxidative stress (OS) status in asthenozoospermic men compared to normozoospermic men. Methods Semen samples were collected from 25 asthenozoospermic men and 28 normozoospermic men. In this study, NOX5 protein expression was evaluated by Western blotting. An OS status was evaluated by measuring of ROS (O-2(-center dot) and H2O2), DNA damage and plasma membrane integrity in spermatozoa. Results The protein expression of NOX5 (p < 0.0001) was remarkably higher in asthenozoospermic men in comparison to normozoospermic men. In addition, the percentages of intracellular O-2(-center dot) (p < 0.0001), H2O2 (p < 0.0001) in viable spermatozoa, apoptotic sperm cells with altered plasma membrane (p < 0.001) and DNA damage (p = 0.001) were significantly increased in asthenozoospermic men compared to normozoospermic men. Conclusions The present study provides evidence that the overexpression of NOX5 protein may induce excessive ROS production and oxidative stress damages to DNA and plasma membrane integrity in asthenozoospermic men.