実験的骨格筋萎縮の研究
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概要
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In the present study, 105 healthy female albino rabbits weighing 1070 g to 3500g were used. They were divided into two groups; one with sectioned sciatic nerve and one immobilized by a plaster cast (which consisted of 3 groups-plantar flexion position, 90°C, flexion and dorsal positions at ankle joint) . Manifestation modality of muscular atrophy on tibialis anterior was tested histologically and observed under a scanning electron microscopy (SEM) at regular intervals for five weeks. The following results were obtained: 1) The tibialis anterior of rabbits was divisible into three different color groups by Sudan Black B staining; white muscle fiber, red muscle fiber and an intermediate muscle fiber. Distribution in each muscle fiber was 46.5 % white, 28.4 % red and 25.1 % intermediate. Large amounts of white muscle fiber were found in the outermost muscle layer, while red was found in the deeper layer. Under scanning electron microscopic observation, the number of muscle fibers in each intraperimysium was 12 to 43. The diameter of muscle fibers was 8 to 70 dim, and the cross-section was polygonal (quadranqular, pentagonal and hexagonal) . 2) From the beginning, muscle weight decreased in the sectioned nerve group. Muscle weight initially increased and then decreased in the plaster cast immobilized group. 3) Great muscle fiber change was noted in the outermost layers of both groups. Changes such as atrophy developed earlier and to a greater extent in the sectioned nerve group than in the cast immobilized group. 4) In the cast immobilized group, muscle fiber of tibilias anterior developed a tendency to become round and expand earlier in the extension and intermediate positions than in the flexion position. 5) The above phenomena were remarkably revealed in white muscle fiber. Accordingly, atrophy often appeared in the outermost muscle layer, which include great amounts of white muscle fiber. 6) As for SEM, the sectioned group more cleared showed muscle fiber coarseness, connective tissue growth in intermuscle bundles and vascuolar degeneration than did the group immobilized by plaster casts. Those changes were more marked in the extension and intermediate positions than in the flexion. It was remarkable that such a large diameter of muscle should be of the white kind. 7) Prophylactic measures against muscle atrophy were considered on the basis of these results.
- 昭和大学・昭和医学会の論文