Fig. 3.

A: representative section from a GTN muscle of an 8-mo-old WT mouse stained with antibodies for slow (red) and fast (blue) myosin and laminin (green) to designate the outline of fibers. Total number of fibers (B) and average cross-sectional areas (CSAs; μm²; C) in cross sections of GTN muscles of WT and CuZnSOD-deficient (Sod1^−/−) mice of varying ages are shown. D: histograms show the distribution of CSAs for fibers in cross sections of GTN muscles of WT and CuZnSOD-deficient (Sod1^−/−) mice at 20 mo of age. B and C: values are means ± 1 SE. Significant difference from *WT value at the same age, **8-mo-old mice of the same genotype, and ***20-mo-old mice of the same genotype: P < 0.05.