The plasticity of denervated and reinnervated laryngeal muscle: focus on single-fiber myosin heavy-chain isoform expression.
The plasticity of denervated and reinnervated laryngeal muscle: focus on single-fiber myosin heavy-chain isoform expression.
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DOI：
10.1001/archotol.130.9.1070
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发表时间：
2004-09
期刊：
影响因子：
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通讯作者：
Y. Z. Wu;M. Baker;J. Marie;R. Crumley;V. Caiozzo
中科院分区：
文献类型：
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作者：
Y. Z. Wu;M. Baker;J. Marie;R. Crumley;V. Caiozzo
目前还没有研究探讨去神经支配对喉肌肌球蛋白重链（MyHC）亚型单纤维分布的影响。快速IIB型MyHC亚型代表环杓后肌（PCA）和甲杓肌（TA）中肌球蛋白池的最大比例。然而，快速IIB型MyHC亚型在单纤维水平上分布不同。因此，我们假设去神经支配将导致在单纤维水平上MyHC亚型表达的明显不同的模式。为了验证这一假设，我们将动物分为以下3组：（1）对照组;（2）去神经组;或（3）神经再支配组。在去神经或再神经支配后7、14、30、90和180天处死动物。随后，在大约7200个单纤维中测定了MyHC亚型的分布。从这项研究中出现了4个关键发现：（1）在整个肌肉和单纤维水平上，PCA肌肉的MyHC亚型分布比TA肌肉更具延展性。(2)在PCA和TA肌肉中，去神经支配产生了一些类似的变化，导致共表达快速IIX型和IIB型MyHC亚型的纤维池大量增加。(3)TA肌肉的神经再生产生了显着的改变，在单纤维分布的MyHC亚型，而对整个肌肉的MyHC亚型组合物的影响不大。(4)由于与失神经支配相关的MyHC亚型表达的转变主要限于快速IIB型到快速IIX型，我们假设肌肉功能仅会轻微降低（由最大缩短速度和力-速度关系定义）。
No studies have examined the effects of denervation on the single-fiber distribution of myosin heavy-chain (MyHC) isoforms in laryngeal muscle. The fast type IIB MyHC isoform represents the largest proportion of the myosin pool in the posterior cricoarytenoid (PCA) and the thyroarytenoid (TA) muscles. However, the fast type IIB MyHC isoform is distributed differently at the single-fiber level. Hence, we hypothesized that denervation would result in markedly different patterns of MyHC isoform expression at the single-fiber level. To test this hypothesis, we assigned animals to the following 3 groups: (1) control group; (2) denervation group; or (3) reinnervation group. Animals were killed 7, 14, 30, 90, and 180 days after denervation or reinnervation. Subsequently, the distribution of MyHC isoforms were electrophoretically determined in approximately 7200 single fibers. There were 4 key findings to emerge from this study: (1) The MyHC isoform profile of the PCA muscle, at both the whole-muscle and single-fiber level, is more malleable than that of the TA muscle. (2) In the PCA and TA muscles, denervation produced some similar changes, resulting in a large increase in the pool of fibers coexpressing fast type IIX and IIB MyHC isoforms. (3) Reinnervation of the TA muscle produced significant alterations in the single-fiber distribution of MyHC isoforms while having little effect on the whole-muscle MyHC isoform composition. (4) Since the transitions in MyHC isoform expression associated with denervation were limited primarily to fast type IIB to fast type IIX, we postulate that only minor reductions in muscle function would result (as defined by maximum shortening velocity and the force-velocity relationship).