Extreme stretch growth of integrated axons
Extreme stretch growth of integrated axons
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DOI：
10.1523/jneurosci.1974-04.2004
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发表时间：
2004-09-08
影响因子：
5.3
通讯作者：
Smith, DH
中科院分区：
文献类型：
--
作者：
Pfister, BJ;Iwata, A;Smith, DH
大型动物在发育过程中可以经历巨大的生长，这表明神经和白色物质束中的轴突也会迅速扩张。因为整合的轴突没有生长锥延伸，所以已经假设机械力可以刺激轴突伸长以匹配动物的生长。然而，这种独特的形式的快速和持续增长的综合轴突从未被证明。在这里，我们使用了微步进电机系统，以评估在几天到几周的培养中，拉伸率的上升对整合轴突束的影响。我们发现轴突束可以以8 mm/d的速率拉伸生长，并达到10 cm的长度而不断开。尽管动态和长期的伸长，拉伸轴突增加了35%的口径，而细胞骨架成分和细胞器的形态和密度保持不变。这些数据提供了第一个证据表明，机械刺激可以诱导极端的“拉伸生长”的综合轴突束，远远超过任何以前观察到的限制轴突生长。
Large animals can undergo enormous growth during development, suggesting that axons in nerves and white matter tracts rapidly expand as well. Because integrated axons have no growth cones to extend from, it has been postulated that mechanical forces may stimulate axon elongation matching the growth of the animal. However, this distinct form of rapid and sustained growth of integrated axons has never been demonstrated. Here, we used a microstepper motor system to evaluate the effects of escalating rates of stretch on integrated axon tracts over days to weeks in culture. We found that axon tracts could be stretch grown at rates of 8 mm/d and reach lengths of 10 cm without disconnection. Despite dynamic and long-term elongation, stretched axons increased in caliber by 35%, while the morphology and density of cytoskeletal constituents and organelles were maintained. These data provide the first evidence that mechanical stimuli can induce extreme "stretch growth" of integrated axon tracts, far exceeding any previously observed limits of axon growth.