MYOSIN HEAVY-CHAIN COMPOSITION OF SINGLE FIBERS AND THEIR ORIGINS AND DISTRIBUTION IN DEVELOPING FASCICLES OF SHEEP TIBIALIS CRANIALIS MUSCLES
MYOSIN HEAVY-CHAIN COMPOSITION OF SINGLE FIBERS AND THEIR ORIGINS AND DISTRIBUTION IN DEVELOPING FASCICLES OF SHEEP TIBIALIS CRANIALIS MUSCLES
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DOI：
10.1007/bf01737997
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发表时间：
1992-10-01
影响因子：
2.7
通讯作者：
HARRIS, AJ
中科院分区：
文献类型：
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作者：
MAIER, A;MCEWAN, JC;HARRIS, AJ
用抗肌球蛋白重链(MHC)同工酶的单抗对绵羊胫骨颅肌发育过程中肌球蛋白重链(MHC)同工酶的组成进行了免疫组织化学研究。用常规显微镜和计算机图像分析技术从胚胎第76天到出生后第20天和成年动物收集数据。E76时，23%的年轻肌纤维染色为慢抽动MHC。这些纤维的数量远远超过了初级和次级肌管的数量。到E100时，较小的纤维包裹着最初种群中的每一根纤维形成玫瑰花环，这些纤维对慢抽动MHC呈阴性反应。在玫瑰花丛之间的空隙中出现了第二批小纤维。细小纤维，无论是否属于玫瑰花环，最初并不表达慢抽动的MHC，而是主要表达新生儿肌球蛋白。然后，这些细小的纤维分成三个独立的组。在第一组中，大多数纤维瞬时表达成人快速肌球蛋白(在E110-E120达到最大值)，但在成人中表达慢速肌球蛋白。这种向慢MHC表型的转变始于E110，在出生后20天接近完成，约占成年慢抽动纤维种群的60%。成体FAST MHC在另两组均有表达，占成体纤维总数的14%和17%。我们得出结论，在这块巨大的肌肉中，肌肉纤维的形成至少涉及三代肌管。次级肌管是在初级肌管的框架上产生的，两个种群都分化成年轻的肌纤维，我们在E76观察到这些年轻的肌纤维形成了玫瑰花环。第三级肌管以玫瑰花环的外层纤维为支架，出现在花环之间的空隙和束束的边缘。
The myosin heavy chain (MHC) composition of single muscle fibres in developing sheep tibialis cranialis muscles was examined immunohistochemically with monoclonal antibodies to MHC isozymes. Data were collected with conventional microscopy and computerized image analysis from embryonic day (E) 76 to postnatal day (PN) 20, and from adult animals. At E76, 23% of the young myofibres stained for slow-twitch MHC. The number of these fibres considerably exceeded the number of primary and secondary myotubes. By E100, smaller fibres, negative for slow-twitch MHC, encircled each fibre from the initial population to form rosettes. A second population of small fibres appeared in the unoccupied spaces between rosettes. Small fibres, whether belonging to rosettes or not, did not initially express slow-twitch MHC, expressing mainly neonatal myosin instead. These small fibres then diverged into three separate groups. In the first group most fibres transiently expressed adult fast myosin (maximal at E110-E120), but in the adult expressed slow myosin. This transformation to the slow MHC phenotype commenced at E110, was nearing completion by 20 postnatal days, and was responsible for approximately 60% of the adult slow twitch fibre population. In the other two groups expression of adult fast MHC was maintained, and in the adult they accounted for 14% ala MHC) and 17% (IIb MHC) of the total fibre numbers. We conclude that muscle fibre formation in this large muscle involves at least three generations of myotube. Secondary myotubes are generated on a framework of primary myotubes and both populations differentiate into the young myofibres which we observed at E76 to form rosettes. Tertiary myotubes, in tum, appear in the spaces between rosettes and along the borders of fascicles, using the outer fibres of rosettes as scaffolds.