Objectives: Radical oxidative  species  (ROS)  have an important effect on  sperm quality and quantity. Oxidative stress (OS) occurs when production of potentially destructive reactive oxygen species (ROS) exceeds the body’s own natural antioxidant defenses, resulting in  cellular damage.  OS is  a  common pathology seen in  approximately  half of  all  infertile men. Increased ROS  generation and reduced antioxidant capacity is negatively correlated with sperm concentration and motility in infertile men. For the first time, we  used a more stable and reliable sensitive carbonyl protein (CP) detection method to determine ROS in seminal plasma than measuring ROS directly to clarify the effect of OS on spermatozoa in terms of protein dysfunction. This is the first report to measure CP in seminal plasma as an indicator of OS. Furthermore, for the first time we  correlated the results of CP measurement with light microscopy in combination with ultrastructural analysis by  electron microscopy.

Material and Methods: 20  patients with idiopathic oligoasthenoteratozoospermia (iOAT) and 10  fertile controls were enrolled in this study. CP values were measured by enzyme-linked immuno sorbent assay (ELISA) to detect the level of OS. Transmission electron microscope (TEM) was used to detect axonemal anomalies.

Results: Compared to fertile controls, statistically highly significant higher degrees of abnormal sperm parameters (P < 0.001) could be  found in iOAT patients. CP values were highly significantly elevated in iOAT patients than in normal controls (P < 0.001). A statistically highly significant difference in different axonemal anomalies were found between iOAT patients and normal controls (P < 0.001). CP values have been found to  be   positively correlated  with  different axonemal anomalies (absence of  axoneme (r2 = 0.841), missing  of  central singlet tubules  (r2 = 0.702) and  missing of  outer  doublet tubules (r2 = 0.869). A statistically negative correlation were found between  different axonemal anomalies (absent axoneme (r2 =  0.780), missing of  central singlet tubules (r2 = 0.611), and missing of  outer doublet tubules (r2 = 0.738) and forward progressive sperm motility.

Conclusion: High levels of CP can be  measured in  iOAT patients, indicating that OS could underlie the aetipopathogenesis of the syndrome. OS negatively affects flagellar axonemal structure with subsequent impairment of  forward progressive sperm motility. This  can put an attention for  antioxidants as  a therapy for  iOAT syndrome and further research to find how to decrease ROS production.