Department of Equine Sciences, Faculty of Veterinary Medicine, Utrecht University, the Netherlands; Regenerative Medicine Utrecht, Utrecht University, Utrecht, the Netherlands.
Research Unit of Medical Imaging, Physics and Technology, Faculty of Medicine, University of Oulu, Oulu, Finland.
Bone. 2019 Oct;127:664-673. doi: 10.1016/j.bone.2019.07.001. Epub 2019 Jul 3.
Since Galileo's days the effect of size on the anatomical characteristics of the structural elements of the body has been a subject of interest. However, the effects of scaling at tissue level have received little interest and virtually no data exist on the subject with respect to the osteochondral unit in the joint, despite this being one of the most lesion-prone and clinically relevant parts of the musculoskeletal system. Imaging techniques, including Fourier transform infrared imaging, polarized light microscopy and micro computed tomography, were combined to study the response to increasing body mass of the osteochondral unit. We analyzed the effect of scaling on structural characteristics of articular cartilage, subchondral plate and the supporting trabecular bone, across a wide range of mammals at microscopic level. We demonstrated that, while total cartilage thickness scales to body mass in a negative allometric fashion, thickness of different cartilage layers did not. Cartilage tissue layers were found to adapt to increasing loads principally in the deep zone with the superficial layers becoming relatively thinner. Subchondral plate thickness was found to have no correlation to body mass, nor did bone volume fraction. The underlying trabecular bone was found to have thicker trabeculae (r=0.75, p<0.001), as expected since this structure carries most loads and plays a role in force mitigation. The results of this study suggest that the osteochondral tissue structure has remained remarkably preserved across mammalian species during evolution, and that in particular, the trabecular bone carries the adaptation to the increasing body mass.
自伽利略时代以来，大小对身体结构元素的解剖学特征的影响一直是人们关注的话题。然而，在组织水平上的缩放效果几乎没有引起人们的兴趣，实际上在关节的骨软骨单位方面，几乎没有关于这个主题的数据，尽管这是肌肉骨骼系统中最容易出现病变和最具临床相关性的部分之一。成像技术，包括傅里叶变换红外成像、偏光显微镜和微计算机断层扫描，被结合起来研究骨软骨单位对体重增加的反应。我们在微观水平上分析了在广泛的哺乳动物中，缩放对关节软骨、软骨下板和支撑性小梁骨的结构特征的影响。我们证明，虽然总软骨厚度以负异速生长的方式与体重成比例，但不同软骨层的厚度却不成比例。发现软骨组织层主要在深层区域适应增加的负荷，而浅层区域变得相对较薄。软骨下板厚度与体重无关，骨体积分数也无关。发现底层小梁骨的小梁较厚（r=0.75，p<0.001），这是意料之中的，因为这种结构承受着大部分负荷，并在减轻力方面发挥作用。这项研究的结果表明，在进化过程中，骨软骨组织结构在哺乳动物物种中保持着惊人的保存，特别是小梁骨承载着对体重增加的适应。
