Influence of maturity on nucleus–endplate integration in the ovine lumbar spine
Influence of maturity on nucleus–endplate integration in the ovine lumbar spine
复制标题
成熟度对绵羊腰椎核-终板整合的影响
作者：
K. Wade;P. Robertson;N. Broom
目的：最近对绵羊脊柱模型的研究表明，椎间盘核包含一个高度卷曲的纤维网络，具有端板到端板的连接，这种连接是通过独特的节点附着点实现的。本研究的目的是探讨这种节点锚定系统如何受到成熟的影响。方法从新生、3个月、12个月和完全成熟的绵羊中分离出运动节段，采用新颖的环形环切断程序去除环的应变限制影响，然后进行机械破坏试验或显微结构和超微结构检查。在相对较薄的切面内分析节点的形态及其线密度，为四个年龄组之间的比较提供依据。结果环切断后的力学测试表明，所有样品中剩余的核材料，无论成熟度如何，都具有在端板之间传递大量载荷的能力。来自所有年龄组的环切断样本在拉伸但未破裂状态下的成像显示，在核区域存在轴向排列的纤维化，与终板到终板的连通性一致。所有年龄组均观察到终板插入淋巴结。超微结构检查显示新生椎间盘淋巴结的纤维结构与成熟椎间盘淋巴结相似。然而，在出生到3个月之间，它们的线性密度迅速增加，此后保持不变。结论先前在成熟的羊椎间盘中发现的淋巴结附着点也存在于新生、3和12个月大的动物中，在出生到3个月之间，它们的线性密度最初迅速增加，之后保持不变。所有年龄段的附着点的大小和形态相似。我们的研究表明，羊椎间盘终板中淋巴结密度的增加是对椎间盘从出生到成熟所处的负荷环境的适应性反应的一部分。
PurposeRecent investigations using an ovine spine model have established that the disc nucleus contains a highly convoluted fibre network with endplate-to-endplate connectivity, this connectivity being achieved via distinctive nodal attachment points. The purpose of this study was to investigate how this nodal anchoring system might be influenced by maturation.MethodsLumbar motion segments were dissected from newborn, 3, 12 months and fully mature ovine animals, subjected to a novel annular ring-severing procedure to remove the strain-limiting influence of the annulus, then either mechanically tested to destruction or examined microstructurally and ultrastructurally. The morphology of the nodes and their linear density within the relatively thin section planes were analysed to provide a basis for comparison between the four age groups.ResultsMechanical testing following ring severing revealed that the remaining nuclear material in all samples, irrespective of maturity, had the ability to transmit a substantial load from endplate to endplate. Imaging of the ring-severed samples from all age groups in their stretched, but unruptured state revealed the presence of axially aligned fibrosity in the nucleus region consistent with endplate-to-endplate connectivity. Endplate insertion nodes were observed in all age groups. Ultrastructural examination revealed that the fibrillar architecture of these nodes in the newborn discs was similar to that observed in the nodes of mature discs. However, there was a rapid increase in their linear density between birth and 3 months, after which this remained constant.ConclusionsThe nodal attachment points identified previously in mature ovine discs are also present in newborn, and 3- and 12-month-old animals with an initial rapid increase in their linear density between birth and 3 months, after which it remained constant. The size and morphology of the attachment points were similar for all ages. Our study suggests that the increase in nodal density in the ovine disc endplate is part of an adaptive response to the loading environment that the disc is exposed to from birth to maturity.