Determination of superoxide dismutase and glutathione peroxidase activities in blood of healthy pediatric subjects

Background: Given the growing requirement of antioxidant enzymes measurements in laboratory and the increasing role of SOD/GPx ratio in the balance of reactive oxygen species (ROS), the aim of our study was to contribute to define reference values of enzyme activities in Italian healthy children, by determining SOD in erythrocytes and GPx in whole blood. Methods: SOD (E.C.1.15.1.1) and GPx (E.C.1.11.1.9) activities were spectrophotometrically assayed in erythrocytes with commercial kits. SOD activity was expressed as the amount of protein causing a 50% inhibition of formazan dye (505 run), employing xanthine and xanthine oxidase to generate superoxide radicals. Units of GPx activity were calculated following NADPH oxidation at 340 nm using cumene hydroperoxide as the substrate. Results: Superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were assayed in blood of 45 healthy pediatric subjects (26 males and 19 females between 0 and 14 years of age). We found no significant differences in blood antioxidant enzymes both in all population and when we distributed the subjects for age classes and sex. Conclusion: the definition of pediatric values of antioxidant enzyme activities in blood of healthy children may be useful in monitoring SOD and GPx in physiologic and pathologic conditions, also for future therapeutic trials. (C) 2002 Elsevier Science B.V. All rights reserved.