Skeletal Muscle Antioxidant Antioxidant Capacity Correlates With Both Oxidative And Glycolytic Profile In Trained Women Athletes

Abstract

Muscle antioxidant enzymes may be upregulated in parallel with increased exercise training status and capacity for reactive oxygen species (ROS) formation. PURPOSE: To examine associations between antioxidant protein expression and different physiological markers of endurance exercise in trained women athletes. METHODS: Seventeen competitive women soccer players (age; 23±4 yrs; height; 166±5 cm, weight; 60.2±7.5 kg; VO2max; 50.5±5.1 ml·min-1·kg-1) participated. Participants had a muscle biopsy taken from m. vastus lateralis, which was analyzed for protein expression of superoxide dismutase 1 and 2 (SOD1 and 2), several metabolic enzymes and muscle fiber type profile. Participants also performed a VO2max test, a repeated sprint test (RST), as well as the Yo-Yo Intermittent Endurance, level 1 (YYIE1) and Recovery test, level 1 (YYIR1). Inter-individual relationships between selected variables were analysed using Pearson’s product–moment correlation coefficients. RESULTS: VO2max and SOD2 correlated (P<0.05) with VO2max explaining 24% of the variance in SOD2 protein expression. Myosin Heavy Chain I (MHCI) and IIa (MHCIIa) explained 26 and 25%, respectively, of the variance in SOD2 protein. Oxidative enzymes such as citrate synthase, isocitrate dehydrogenase and cytocrome c oxidase correlated (P<0.05) with SOD2 explaining 24, 31 and 17% of the variance, respectively. Finally, SOD2 protein expression correlated (P<0.05) to monocarboxylate transporter 4 (MCT4; r=0.67) and phosphofructokinase (PFK; r=0.62). No statistical relationship was observed between SOD2 protein and neither Na+-K+ATPase subunits, Na+/H+ exchanger, Acetyl-CoA carboxylase, PECAM-1, nor YYIE1, YYIR1 and RST performance. SOD1 protein expression displayed an inverse correlation with MHCIIa (r=0.61; P<0.05), but did not correlate with any other variable assessed in muscle or physical capacity. CONCLUSIONS: Skeletal muscle antioxidant capacity associates with markers of endurance exercise such as maximal aerobic power, type I and IIa muscle fibers, and mitochondrial function. However, strong relationships were additionally observed between antioxidant profile and lactate production as well as transport capacity, supporting a link between lactate and ROS generation.