Evaluation of Systemic Protein Carbonylation and Glutathione-Dependent Enzymatic Antioxidant Defense Line in Diabetic Foot Syndrome

Objective

Diabetic foot syndrome is a debilitating complication of diabetes mellitus closely tied to chronic metabolic dysregulation. This study aimed to evaluate circulating oxidative protein damage and the status of the glutathione-dependent enzymatic antioxidant defense system in patients with diabetic foot syndrome compared to healthy controls. Materials and Methods: In this case-control study, 59 patients diagnosed with diabetic foot syndrome and 63 age-comparable healthy controls were evaluated. Circulating biochemical parameters—protein carbonyl content (PKD) as a marker of oxidative protein modification, and four antioxidant line parameters: glutathione reductase (GR), glutathione S-transferase (GST), total sulfhydryl/thiol groups (TSH), and glutathione peroxidase (GSHPx)—were assayed. Non-parametric Mann-Whitney U tests, rank-biserial effect sizes, Spearman correlations, receiver operating characteristic (ROC) curves, and principal component analysis (PCA) were conducted.