Histological study on the development of skeletal muscle fibers
- VernacularTitle:骨格筋線維の発達に関する組織学的研究
- Author:
K. Kikuchi
- Publication Type:Journal Article
- From:Japanese Journal of Physical Fitness and Sports Medicine
1967;16(2):38-44
- CountryJapan
- Language:Japanese
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Abstract:
The purpose of this study is to inquire histologically when red muscle fibers and white muscle fibers are differenciated and how they develope, considering from sex difference.
Wistar-strain rats of the same venter were used in this experiment. The animals of both sexes were killed at the interval of five days, from birth to 25 days. Two groups of male and female rats of 70 days old after birth were used as control groups.
M. tibialis ant. was removed and then fixed in 10% formalin for approximately two weeks. As staining, alchohol solution of Sudan black B was used.
The results are as follows :
1) Sex difference in rats' body weight was started to appear about 15 days after birth.
2) Differentiation of red muscle fibers and white muscle fibers in M. tibialis ant. was recognized about 15 days after birth in male and female rats.
3) The entire area of cross section of M. tibialis ant. is increasing during the development of rats' body as a whole. No apparent tendency on sex difference was found till 25 days after birth. On 70 days after birth the entire area of cross section in male has about 1.5 times the size of female.
4) No increase of number in M. tibialis ant. was recognized during the development of rats' body as a whole and no sex difference in number of muscle fibers.
5) The area of cross section per fiber and the average diameter of fibers are increasing during the growth of rats' body. No sex difference of those in red and white muscle fibers was found till 25 days after birth but, on 70 days after birth, it became clear. The rate of hypertrophy of white muscle fibers is greater than that of red muscle fibers.
6) Ratio of the entire area of muscle fibers to the intercelluler space in M. tibi-alis ant. is increasing during the development of rats' body.
7) No difference of area of cross section per fiber in peripheral and innermost regions was found till about 15 days after birth. On 70 days after birth the red muscle fibers in peripheral have 1.4 times the size of those in innermost, and the white muscle fibers 1.3 times.
