Blood reflects tissue oxidative stress depending on biomarker and tissue studied.

This study investigated whether selected oxidative stress markers measured in blood adequately reflect redox status in skeletal muscle, heart, and liver. Several markers were determined after implementing two treatments known to affect redox status, namely exercise and allopurinol administration. Xanthine oxidase, thiobarbituric acid-reactive substances (TBARS), protein carbonyls (PC), reduced glutathione (GSH), oxidized glutathione (GSSG), catalase, and total antioxidant capacity were determined in blood, skeletal muscle, heart, and liver. Correlation between blood and tissues in each marker was performed through the Spearman rank correlation coefficient. GSSG in erythrocytes was correlated with all tissues, ranging in the five experimental groups as follows: skeletal muscle r(s)=0.656-0.874, heart r(s)=0.742-0.981, liver r(s)=0.646-0.855. Xanthine oxidase and TBARS measured in blood satisfactorily described the redox status of the heart (0.753-0.964 and 0.705-1.000, respectively) and liver (0.755-0.902 and 0.656-1.000, respectively). Skeletal muscle and heart redox status can be adequately described by PC (0.652-1.000 and 0.656-0.964, respectively), GSH (0.693-1.000 and 0.656-1.000, respectively), and catalase (0.745-1.000 and 0.656-1.000, respectively) measured in blood. In conclusion, this study suggests that a combination of markers measured in blood provides a reliable indication about the redox status in skeletal muscle, heart, and liver.