2002 Fiscal Year Final Research Report Summary
An origin and role of myogenic cell except a satellite cell appearing at hyperttophied skeletal muscle tissue.
| Project/Area Number |
13680015
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
体育学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
YAMADA Shigeo Graduate School of Arts and Sciences, Associate Professor, 大学院・総合文化研究科, 助教授 (50092367)
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| Project Period (FY) |
2001 – 2002
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| Keywords | Muscle hypertrophy / hepatocvte / albumin / 筋崩壊 |
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| Research Abstract |
It is well known that a skeletal muscle is enlarged by exercise, but is not clear about the hypertrophy mechanism of skeletal muscle now. Skeletal muscle hypertrophy happens by enlargement and an increase of a muscular cell number forming muscular tissue basically. It is known that an increase of a muscular cell is guided by growth factor. The new muscular fiber was formed by proliferation of myogenic cell and it made dear that the myogenic cell were satellite cells. However, although number of a satellite cell decreased with aging either and existence of a myogenic cell except a satellite cell was suggested by an enlargement effect being recognized by a resistance training of an older man. So the possibility about an origin and role of a myogenic cell except a satellite cell was examined .Mechanism of the muscular fiber hypertrophy which was hardly observed till now, studied in Chapter 1. As a result of this experiment, hypertrophy of the muscular fiber, increase of muscular fiber len
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gth, increase of a nucleus in muscular fiber were observed dearly. Furthermore, the capacity of cytoplasm per a nucleus of control group and exercise group was almost a constant ratio. After the skeletal muscle fiber was formed in development stage the muscle fiber has never divided. Accordingly, as for the cause that a nucleus increased with hypertrophied muscular fiber, a satellite cell or the result that other myogenic fused to old muscular fiber. The new formation and myogenic cell origin of muscular tissue were examined in Chapter 2. Collapse of muscular fiber make progress with exercise dearly, and it made ft dear by vital staining method that the new formation of muscular tissue began. A myogenic cell origin by observing a positive cell of myogenin which was a transcription factor peculiar to a muscular cell was examined As a result of observation, positive myogenin cells were observed in blood vessel arid its circumference side and suggested possibility carried to muscular tissue through blood. In addition, the albumin positive cells which specifically appeared and secreted with a liver cell, were observed with muscular tissue identically. It was suggested that a liver stem cell functioned with a myogenic cell by these experiments. Swimming exercise as an exercise model was used in Chapter 3.
This model is more realistic than a tenotomy model. The influence that exfoliation of a liver cell and a liver stem cell from a fiver gave to liver weight was examined As a result these experiments, weight of a liver deteriorated obviously, and, as for the sole muscle that was antigravity muscles, the weight increased with swimming exercise. From a result as the above, a liver supplies a myogenic cells to muscular tissue in muscle hypertrophy and regeneration with exercise, and it supplies has an important role on the muscular tissue architecture that adapted itself to exercise. Less
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