Screening of Oxidative Stress Biomarkers and Inflammatory Cytokines in the Pathogenesis of Diabetic Neuropathy

Abstract

Diabetic neuropathy is a neurological syndrome characterized by severe pain and significant mortality caused primarily by somatosensory nerve system damage. In DN patients, the structural and functional damages of neurons are caused by variety of factors. Among these factors, the production of free radicals serves as significant contributors to DN. In addition, hyperglycemia causes chronic inflammation and metabolic changes in neuronal tissues by producing variety of proinflammatory cytokines which serve a significant role in the pathophysiology of DN. Hence, the present study aimed to determine the levels of oxidative stress indicators like SOD, CAT, GR and GPX, as well as proinflammatory cytokines like IL-2, IL-4 and IL-6 in patients with DN in comparison to healthy subjects. The results demonstrated that the mean glucose levels in DN patients range from 142.6±7.2 to 168.1±8.2 mg/dl. The Hb levels exhibited negative correlation in both the DN patients and healthy controls with age. In DN patients, enzymatic antioxidants including SOD, CAT, GR and GPX exhibited significantly decreased activity than the healthy individuals and they exhibited strong negative correlations such as r = -0.943, r = -0.819, r = -0.969 and r = -0.973 respectively. The mean TAS levels in DN patients range from 0.93±0.1 to 0.37±0.02 mM FE with increasing age. Additionally, proinflammatory cytokines such as IL-2, IL-4 and IL-6 levels in DN patients were observed in the ranges of 2.48±1.2 to 3.97±1.5, 41.15±3.7 to 56.43±4.3, 7.61±2.1 to 10.24±1.8 pg/ml respectively with increasing age. The present study concluded that patients with high inflammatory marker levels had elevated oxidative stress, demonstrating that oxidative stress and inflammation are important pathophysiological factors in DN.