Diagnostic sensitivity and specificity of indicators of glutathione antioxidant system in spermatozoa of infertile men with different forms of pathospermia

Background. One of the most important antioxidant defence mechanism in spermatozoa is the gluthatione system which includes glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST) and reduced glutathione (GSH). It is promising to use ROC analysis, which allows to assessing the diagnostic sensitivity and specificity of indicators. Materials and methods. Infertile men were divided into 3 groups: patients with oligozoospermia (n = 30), asthenozoospermia (n = 34), and oligoasthenozoospermia (n = 22). To assess the diagnostic sensitivity and specificity of indicators, the values of the biomarkers were tested using the receiver operating characteristic (ROC) curve, and the area under it (AUC), the standard error (SE) and the 95% confidence interval (CI 95%) were calculated. Results. The ROC analysis showed that GP activity was characterized by excellent diagnostic significance for diagnosing both oligozoospermia and asthenozoospermia (the sensitivity was 100%, and specificity – 100%). The GR activity has moderate diagnostic significance, since the AUC is 0.654 (95% CI from 0.503 to 0.785, P = 0.0645) for oligozoospermic, the AUC is 0.612 (95% CI from 0.454 to 0.7555, P = 0.1979) for asthenozoospermic men. The analysis of the ROC curve revealed a good diagnostic value of GsT activity in sperm samples for the diagnosis of pathospermia (sensitivity of 75% and specificity of 80%). Simultaneously, it was shown that GSH content could not serve as valuable biomarkers for distinguishing patients with pathospermia from healthy controls, with an AUC of 0.615, corresponding to moderate diagnostic significance for oligozoospermia. Conclusion. The results of this study show that the cut-off points for the biomar­kers glutathione peroxidase and glutathione-S-transferase can be used to distinguish between patients with pathospermia and normozoospermia, and the parameters themselves can serve as valuable diagnostic biomarkers to distinguish patients with pathospermia from healthy controls, regardless of the causes of pathospermia. The value of these indicators below the cut-off point indicates the probable presence of pathology. Indicators of GR activity and GSH content have a low diagnostic value, which makes them unsuitable for use as laboratory tests for the diagnosis of male infertility.