局所麻酔剤 (塩酸ブピバカイン) 注入による骨格筋線維の変性, 崩壊と再生過程における組織化学的研究

抄録

The present study was attempted to elucidate histochemical characteristics of destruction and regeneration of skeletal muscle fibers with injection of a local anesthetic drug.
After single injection of 0.3 ml of 0.5% bupivacaine hydrochloride (BH) into the rat masseter, soleus and gastrocunemius muscles, the animals were killed at 1, 3, 5, 7, 14, 21 and 28 days. Fresh frozen sections fixed with isopentane into liquid nitrogen were made at 10 μm in -20°C cryostat for myosin ATPase, SDH, AchE and laminin. The others were fixed with 2% glutaraldehyde and embedded in EPON 812 for electronmicroscopy. The skeletal muscle fibers were classified into 4 types (I, II A, II B and II C) according to Brooke and Kaiser's procedure with myosin ATPase with acid and alkaline pre-incubation.
At 1 and 3 days following BH injection, affected muscle fibers showed plasma membrane degeneration, but remaining basal lamina and AchE activity in synaptic junction were detected to be without degeneration. After 5 days, satellite cells grew in numbers at the basal lamina of muscle fibers, and from 7 to 14 days, extensive regeneration of muscle fibers appeared. Immunohistochemically detectable laminin staining clearly existed in the basal lamina in those degenerated and regenerated muscle fibers. Degenerated muscle fibers of the 7 days specimens generally showed 11 C type fibers and strong SDH activity. In 14 to 28 days after BH injection, type II C fibers transformed into either type I, II A or II B fibers.