Associations Between Plasma Antioxidant Capacity And Skeletal Muscle Antioxidant Gene Expression

Oxidative stress has been implicated in the etiology of nearly all chronic diseases, including type 2 diabetes, cardiovascular disease, and cancer. In order to maintain redox homeostasis, exogenous antioxidants can be consumed in the diet and endogenous antioxidant enzymes, such as superoxide dismutase (SOD), can be produced within the cells. Antioxidant capacity is often measured in plasma, skeletal muscle, and other cellular compartments within the body. The purpose of this study was to assess associations between plasma antioxidant capacity and skeletal muscle antioxidant gene expression. This study recruited 15 healthy females (BMI=30.97 + 7.87, age=56.5 + 13.4 years) for cross‐sectional analysis. The oxygen radical absorbance capacity assay (ORAC) was used to assess antioxidant capacity in the plasma. Gene expression of SOD1 and SOD2 was assessed in the skeletal muscle from the vastus lateralis using RT‐PCR. The primary finding from this study was a positive association between plasma antioxidant capacity and skeletal muscle SOD1 (r=0.855, p<0.001) and SOD2 (r=0.712, p=0.003) gene expression, suggesting that antioxidant capacity measured in the plasma may be reflective of the antioxidant status within the skeletal muscle. These findings are important given the invasiveness and cost of performing muscle biopsies. While future work needs to be performed to confirm and further validate these findings, these data suggest a more simplistic approach of assessing antioxidant capacity of the plasma may also be reflective of antioxidant status in other tissue compartments.