Hassenkam Tue, Jørgensen Henrik L, Lauritzen Jes Bruun
Nano-Science Center, University of Copenhagen, Copenhagen, Denmark.
Anat Rec A Discov Mol Cell Evol Biol. 2006 Oct;288(10):1087-94. doi: 10.1002/ar.a.20376.
Understanding bone remodeling is essential for understanding bone as a whole. Bone remodeling takes place through a stepwise cellular process, with osteoclasts carving small cavities, also known as resorption pits, into the surface of trabecular bone, followed by osteoblasts, which refill the pits with new soft bone collagen matrix tissue (osteoid). The detailed structure of the surface in the frontier of a resorption pit before, during, and after the osteoid is being laid down is not well known. We present detailed atomic force microscope (AFM) images from the edge, the front end, and the bottom of a resorption pit in a human trabecular bone sample that showed signs of incomplete remodeling. The images reveal a scalloped surface left behind by the osteoclasts and the surface morphology of preexisting bone tissue and new bone tissue. In addition, we display the bone formation front in the pit showing the anchor points between the new bone and the existing bone. We also found evidence of microcracking in the front end of the pit, suggesting that microcracking was the initiator of this particular resorption pit. We anticipate that AFM may initiate a more detailed understanding of the influence of the remodeling process on the structure of bone, as well as a better understanding of the surface on which new bone tissue can be anchored.
了解骨重塑对于全面理解骨骼至关重要。骨重塑通过一个逐步的细胞过程进行，破骨细胞在小梁骨表面开凿小腔隙，即所谓的吸收陷窝，随后成骨细胞用新的软骨胶原基质组织（类骨质）填充这些陷窝。在类骨质沉积之前、期间和之后，吸收陷窝前沿表面的详细结构尚不清楚。我们展示了来自人小梁骨样本中一个吸收陷窝边缘、前端和底部的详细原子力显微镜（AFM）图像，该样本显示出不完全重塑的迹象。这些图像揭示了破骨细胞留下的扇贝状表面以及原有骨组织和新骨组织的表面形态。此外，我们展示了陷窝内的骨形成前沿，显示了新骨与现有骨之间的锚定点。我们还在陷窝前端发现了微裂纹的证据，表明微裂纹是这个特定吸收陷窝的起始因素。我们预计，原子力显微镜可能会引发对重塑过程对骨结构影响的更详细理解，以及对新骨组织能够锚定的表面的更好理解。
