Figure 4. Histochemical analysis of muscle.

Representative results showing frozen sections of the soleus muscle from 8-month-old non-transgenic (A, E, I), CAG₀ ^-24 (B, F), CAG₂₃-11 (C, G, K) and CAG₂₀₀-32 (D, H, J, L) animals. (A–D) Staining for succinate dehydrogenase (SDH). Note that normal fibers show very little reaction, whereas “ragged blue” fibers (arrows) are detected in lines CAG₂₀₀-32 (D) and CAG₂₀₀-62 (data not shown). (E–J) Staining for NADH-tetrazolium reductases. Note the altered fiber type grouping, moth-eaten patterns, and focal lack of intermyofibrillar network enzyme activity (H, J, arrows) in CAG₂₀₀ mice compared to clear fiber type distinctions (E–G) and uniform lattices (I) in control animals. (K, L) Staining for ATPase activity at pH 4.3. Type I fibers are black and type II fibers are cream. Type I predominance is seen in CAG₂₀₀ mice (L). A–H, 160×; I–J, 400×; K–L, 250×.