Micromorphological aproaches to bone resorption and formation

在这项研究中，使用了小鼠。用扫描电镜检查骨骼。1)为减小骨体积，于3周龄切除坐骨神经和股神经，神经切除后观察股骨。神经切断后1 ~ 2周，股骨骨形成激活，2 ~ 5周，海绵骨因骨吸收而减少。骨长正常，骨薄，骨质疏松，呈海绵状。2)为增加骨体积，4周龄时注射雌二醇。注射后3 d，股骨内海绵骨明显减少，随后海绵骨密度和数量增加，占据骨髓间隙。3)根据破骨细胞皱褶边缘的形态特征，将破骨细胞分为两类。4)成骨细胞投射出细长的细胞过程，它们平行运行，这表明胶原纤维的形成过程在骨基质中平行运行。5)骨成骨基质纤维取向异常、不规则。6)骨巨细胞瘤骨吸收腔隙较深，但与正常腔隙相似，提示骨吸收腔隙是由活化的破骨细胞形成的。

In this study, mice were used. Bones were exzamined by scanning electron microscory.1) To decrease the bone volume, the sciatic never and femoral nerve were cut at 3 weeks of age and the femur was observed after nerve cutting. The femur showed activation of bone formation 1 to 2 weeks after nerve cutting and a decrease of spongy bone due to bone resorption in 2 to 5 weeks. The bone grew to normallength but thin bone with pooly developed spongy bone. 2) To increase the bone volume, estradiole was injected at 4 weeks of age. The femur showed a marked decrease of spongy bone with in 3 days after injecion and then spongy bone inreased in density and amount to occupy the marrow spaces. 3) Osteoclasts were classified into two types according to the morphological features of ruffled borders. 4) Osteoblasts projected thin and long cell processes, which run in parallel orientation, suggesting that the processes involved in formation of collagen fibers running parallel in the bone marix. 5) Bones formed in osteosaroma showed adnormal and irregular orientation of fibers in bone matrix. 6) Bone esorption lacunae at giant cell tumor in bone were deep but similar to normal, suggesting that the lacunae were formed by activated osteoclasts.