Fig. 1.

Examples of data derived from different approaches to study reactive oxygen species (ROS) generation in muscle or muscle fibers. A: reduction in glutathione content of muscles from wild-type mice in vivo following a 15-min period of isometric contractile activity. *Significant difference vs. quiescent. [Redrawn from Vasilaki et al. (90).] B: increase in interstitial superoxide monitored by microdialysis in the gastrocnemius muscle of mice during a 15-min period of isometric contractile activity. *Significant difference vs. polyethylene glycol (PEG)-superoxide dismutase (SOD). [Redrawn from Close et al. (11).] C: increase in intracellular 2′,7′-dichlorofluorescein (DCF) fluorescence from fibers isolated from the flexor digitorum brevis (FDB) muscle of mice and subjected to 15 min of isometric contractile activity in vitro. *Significant difference vs. baseline. [Redrawn from Palomero et al. (66).] D: increase in hydrogen peroxide content (indicated by increased HyPer fluorescence) in fibers isolated from the FDB muscle of mice and subjected to 10 min of isometric contractile activity in vitro. *Significant difference vs. baseline. [Redrawn from Pearson et al. (69).]