Oxidative Stress Biomarkers Evaluation

To evaluate the oxidative stress, the serum contents of SOD, glutathione peroxidase (GSH-Px) and MDA. SOD activity was assessed with the xanthine oxidase method and the absorbance value was measured at 550 nm with a SOD kit (Jiancheng Bioengineering, Nanjing, China). MDA content was assessed with thiobarbituric acid reactive substances assay (Jiancheng Bioengineering, Nanjing, China) and the absorbance value was measured at a wavelength of 532 nm. GSH-Px activity was estimated by the analysis of glutathione in the enzymatic reaction. GSH-Px catalyzed the reduction of GSH in the presence of hydrogen peroxide. One unit of enzyme activity represents a decrease in GSH concentration of 1 μm/ml of serum (Yang et al., 2015 (link)).