Micromorphological approaches to bone resorption and formation

主要通过扫描电子显微镜（SEM）检查小鼠顶骨、股骨和胫骨。通过我们的 EDTA-KOH 方法将成骨细胞、骨细胞和破骨细胞暴露于 SEM 以溶解骨基质。通过 NaOCl 浸渍法或水射流暴露骨基质或类骨质的表面。通过背散射法检查了一些顶骨。注射雌激素或切断下肢神经后，还对股骨和胫骨进行了检查。结果表明或暗示以下内容。 1）骨细胞和成骨细胞是功能不同的细胞，与常见的成骨前体细胞分化。骨细胞出现在成骨细胞层中。 2）成骨细胞在成骨细胞层下表面和类骨质表面之间的狭窄空间中拉长许多平行的、长而薄的细胞质突起，形成平行的狭窄间隙，用于胶原纤维的产生。因此，产生的胶原纤维与骨基质平行。 3)骨细胞通过骨细胞的细胞质突起的牵引而埋入骨基质中，并形成网状结构以检测骨的应力负荷，并通过附着于成骨细胞突起的细胞质突起将压力信息告知成骨细胞。 4) 骨细胞将正在形成的骨板的厚度告知局部成骨细胞。 5) 破骨细胞表现出2种不同功能活动的皱褶边界。破骨细胞在两种功能阶段溶解骨基质。 6) 骨形成和骨吸收在功能上是耦合的。 7) 骨表面的背散射图像显示了骨基质的胶原纤维钙化的各个阶段。

The mouse parietal bone, femur and tibia were examined mainly by scanning electron microscopy (SEM). Osteoblasts, osteocytes, and osteoclasts were exposed for SEM by our EDTA-KOH method to dissolve the bone matrix. The surfaces of the bone matrix or osteoid were exposed by a NaOCl maceration method or water jet. Some of parietal bones were examined by a back scattered method. Femurs and tibias were also examined after estrogen injections or cutting nerves for lower extremities. The results indicate or suggest the followings. 1) Osteocytes and osteoblasts are functionally different cells and differentiated from common osteogenic precursor cells. Osteocytes appears in the layr of osteoblasts. 2) Osteoblasts elongate many, parallel, long and thin cytoplasmic processes in the narrow spaces between the undersurface of the osteoblastic layr and the surface of the osteoid to form parallel narrow gaps for collagen fiber production. Thus, the collagen fibers are produced running parallel for the bone matrix. 3) Osteocytes are buried into the bone matrix by pulling by cytoplasmic processes of osteocytes and form meshwork to detect the stress loading to the bone and inform this information of stress to osteoblasts through the cytoplasmic processes attaching to the osteoblast processes. 4) Osteocytes inform the thickness of the forming bone lamella to the local osteoblasts. 5) Osteoclasts show 2 kinds of ruffled borders of different functional activities. Osteoclasts dissolve the bone matrix in 2 kinds of functional phases. 6) Bone formation and resorption are functionally coupled. 7) Back scattered images of the bone surfaces demonstrate the various stages of calcification of collagen fibers for the bone matrix.