Figure 4.

The effect of exercise on histopathology in normal and gsg^−/− animals. (a) Representative sections of normal and gsg^−/− quadriceps taken from age-matched animals that did (exercised, Right) and did not (non-exercised, Left) undergo the swimming protocol. Normal muscle showed no evidence of exercise-induced degeneration. gsg^−/− muscles also showed no increase in histopathology as a result of exercise. (b) Quantitation of histopathology in age-matched exercised and nonexercised gsg^−/− muscles. Histologic sections from femoral quadriceps (quad.), gastrocnemius (gastroc.), and triceps bracheii (triceps) were scored (blinded) for the presence of adipose tissue, degeneration, and fibrosis on a scale of 0–3. The mean ± SEM is shown. There was no significant difference in histopathology between exercised and nonexercised gsg^−/− animals (P values of 0.80, 0.24, and 0.23, respectively).