Regeneration potency of mouse limbs
Regeneration potency of mouse limbs
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DOI：
10.1111/j.1440-169x.2007.00909.x
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发表时间：
2007-02-01
影响因子：
2.5
通讯作者：
Ide, Hiroyuki
中科院分区：
文献类型：
--
作者：
Masaki, Hideki;Ide, Hiroyuki
与两栖动物相比，哺乳动物的肢体再生能力较低。效力低下的一种解释是哺乳动物缺乏再生截肢的细胞。两栖动物可以用去分化细胞形成胚基，但哺乳动物很少有这样的细胞。在本文中，我们报告了肢体形成，特别是截肢中的骨/软骨形成，因为骨/软骨形成是肢体模式再生的基本步骤。新生小鼠截肢后，在截肢部位观察到断肢骨肥大，随后细胞增殖和软骨形成。然而，没有形成新的骨/软骨元素。因此，我们将小鼠胚胎的肢芽移植到新生小鼠的截肢中。当将转基因绿色荧光蛋白（GFP）小鼠的完整肢芽移植到指关节水平截肢后的肢体残端时，移植的肢芽生长并分化为骨、软骨和软组织，并形成由骨和软骨构成的分段图案。当使用晚期肢芽时，骨骼模式更加复杂。为了检查移植的肢芽是否自主发育肢体或与残肢组织相互作用形成肢体，在移植前将肢芽解离成单细胞并重新聚集。重新聚集的肢芽细胞形成了类似的手指状骨/软骨结构。重新聚集的移植物还形成分段软骨。当骨髓间充质细胞的重新聚集体被移植到残肢中时，这些细胞形成软骨，肢芽细胞也是如此。最后，为了检查没有外源供应细胞的残肢组织中新骨形成的效力，我们移植了含有 BMP-7 的明胶凝胶。 BMP 诱导了几种新骨成分的形成，随后软骨形成。结果表明，残肢的环境组织至少部分允许软骨和骨骼的形成，并且未来通过内源或外源提供感受态细胞将有可能形成肢体。
Mammalians have a low potency for limb regeneration compared to that of amphibians. One explanation for the low potency is the deficiency of cells for regenerating amputated limbs in mammals. Amphibians can form a blastema with dedifferentiated cells, but mammals have few such cells. In this paper, we report limb formation, especially bone/cartilage formation in amputated limbs, because bone/cartilage formation is a basic step in limb pattern regeneration. After the amputation of limbs of a neonatal mouse, hypertrophy of the stump bone was observed at the amputation site, which was preceded by cell proliferation and cartilage formation. However, no new elements of bone/cartilage were formed. Thus, we grafted limb buds of mouse embryo into amputated limbs of neonatal mice. When the intact limb bud of a transgenic green fluorescent protein (GFP) mouse was grafted to the limb stump after amputation at the digit joint level, the grafted limb bud grew and differentiated into bone, cartilage and soft tissues, and it formed a segmented pattern that was constituted by bone and cartilage. The skeletal pattern was more complicated when limb buds at advanced stages were used. To examine if the grafted limb bud autonomously develops a limb or interacts with stump tissue to form a limb, the limb bud was dissociated into single cells and reaggregated before grafting. The reaggregated limb bud cells formed similar digit-like bone/cartilage structures. The reaggregated grafts also formed segmented cartilage. When the reaggregates of bone marrow mesenchymal cells were grafted into the stump, these cells formed cartilage, as do limb bud cells. Finally, to examine the potency of new bone formation in the stump tissue without exogenously supplied cells, we grafted gelatin gel containing BMP-7. BMP induced formation of several new bone elements, which was preceded by cartilage formation. The results suggest that the environmental tissues of the stump allow the formation of cartilage and bone at least partially, and that limb formation will be possible by supplying competent cells endogenously or exogenously in the future.