Oxidative/Antioxidant Balance in Male Infertility: A Comparison of Total Antioxidant Status (TAS), Total Oxidant Status (TOS), Protein Carbonyl Levels, and Total Sulfhydryl Levels

INTRODUCTION: Oxidative imbalance is recognized as a key factor in male infertility. This study aimed to compare systemic redox markers, including total oxidant status (TOS), total antioxidant status (TAS), protein carbonyl levels (PCL), and total sulfhydryl (T-SH) levels, between infertile men and healthy controls.
METHODS: This controlled clinical research involved 40 infertile male subjects and 43 age-matched healthy volunteers with no history of systemic illness. Serum samples obtained from peripheral venous blood were analysed for TAS and TOS using Erel's automated colorimetric methods, T-SH using the modified Ellman method, and PCL by ELISA. Because distributions deviated from normality, groups were compared with the Mann–Whitney U test and results are reported as median (Q1–Q3), with p<0.05 accepted as significant.
RESULTS: Serum TOS and PCL were significantly higher in the infertile group than in controls (TOS: median 2.235 [2.185–2.265] vs 1.080 [1.050–1.110]; PCL: 4.255 [4.220–4.320] vs 2.060 [2.040–2.110]), whereas T-SH was significantly lower (6.260 [6.228–6.322] vs 12.280 [12.250–12.400]). TAS also differed significantly between the groups (5.080 [5.035–5.120] vs 10.250 [10.168–10.310]). All four comparisons were significant (Mann–Whitney U, p<0.001 for each; rank-biserial r=1.00), indicating an increased systemic oxidative burden and reduced antioxidant defence capacity in male infertility.
DISCUSSION AND CONCLUSION: Male infertility was associated with increased systemic oxidative stress and diminished antioxidant capacity. Although concurrent assessment of TOS, TAS, PCL and T-SH may add information on the systemic redox landscape in subfertile men, the clinical utility of these markers remains to be established. Larger, prospective, multicentre studies incorporating semen parameters are required before routine clinical use can be recommended.

Keywords: Male infertility, oxidative stress, total oxidant status, total antioxidant status, protein carbonyl, thiols, antioxidant defense, biomarkers, reactive oxygen species