Muscle transplantation and regeneration in the dystrophic hamster. Part 2. Histochemical studies

Enzyme histochemical studies have been done on auto- and cross-transplanted normal and dystrophic anterior tibialis muscles of the hamster. The transplants ranged in age from a few hours to well over 300 days.Both degenerating and regenerating muscles are metabolically active. Glycogen and phosphorylase disappear very early from the transplants. Degenerating fibres show uniform dark staining with ATPase at pH 9.4. NADH-TR activity tends to be localised within the fibres and the reaction product is clumped.Regenerating myoblasts and myotubes stain uniformly dark for ATPase at pH 9.4. There is low NADH-TR and phosphorylase activity, the reaction product being frequently clumped. The pentose-phosphate shunt appears to be very active in the early regenerates as the myotubes stain intensely for RNA. Acid phosphatase activity is present in all transplants, being mostly localised in the connective tissue sheath round the muscle fibres.Muscles transplanted for 20 or more days have well-developed end-plates and are fully differentiated into fibre types. A clear-cut checkerboard pattern of light and dark fibres is observed in all transplants with ATPase reaction. Type 1 and 2 fibres can also be distinguished with phosphorylase and PAS. The regenerated fibres show little variation in staining with the NADH-TR reaction.No differences were observed between the regenerates from normal or dystrophic muscle in either the normal or dystrophic host.