Micromorphological aproaches to bone resorption and formation

在这项研究中，使用了小鼠。1）为减少骨体积，在3周龄时切断坐骨神经和股神经，观察神经切断后股骨的变化。神经切断后1 ~ 2周，股骨骨形成活跃，2 ~ 5周因骨吸收，松质骨减少。骨长至正常长度，但骨薄，松质骨不发达。2)为了增加骨体积，在4周龄时注射雌二醇。注射后3天股骨松质骨明显减少，随后松质骨密度增加，占骨髓腔的量增多。3)根据破骨细胞皱褶边缘的形态特征，将其分为两类。4)成骨细胞投射出细长的平行排列的细胞突起，提示这些突起参与了骨基质中平行排列的胶原纤维的形成。5)成骨细胞中骨纤维在骨基质中的取向异常、不规则。6)骨巨细胞瘤骨吸收陷窝较深，但与正常骨吸收陷窝相似，提示骨吸收陷窝由活化的破骨细胞形成。

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.