The influence of immobilization on osteocyte morphology
The influence of immobilization on osteocyte morphology
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固定对骨细胞形态的影响
作者：
Burkhard Krempien;C. Manegold;Eberhard Ritz;Jürgen Bommer
对脊髓切断、石膏铸造和坐骨神经剥离固定大鼠进行骨细胞的鉴别计数和电镜观察。在碱性紫红染色的胫骨和股骨（100微米）未钙化基底切片中，骨细胞分化为小（代谢无活性）骨细胞、增大（代谢激活）骨细胞和空腔隙。在甲状旁腺功能正常的大鼠（固定3周）中，甲状旁腺切除术后激活细胞的数量明显增加，而小骨细胞的数量减少。在脊髓切断的动物中，空腔隙的数量也增加。对固定10天的大鼠未钙化胫骨的电镜研究显示，骨膜细胞性骨溶解伴腔壁破坏、胶原纤维断裂和矿物晶体丢失。骨细胞胞浆缝增宽，线粒体增大，胞浆内可见含有无定形物质的空泡。胞浆深度内陷和细胞突增加是典型的表现。研究结果表明，固定可以激活骨细胞代谢。因此，骨细胞在骨质疏松症的发病中起重要作用。甲状旁腺切除术可抑制骨膜细胞性骨溶解。因此，骨细胞对内源性甲状旁腺激素的反应必须在固定条件下改变。
Differential counts and electron microscopical studies of osteocytes were performed on rats immobilized by spinal cord severing, plaster cast and ischiatic nerive dissection. In undecalcified ground sections of tibia and femur (100 micron) stained wtth basic fuchsin, osteocytes were differentiated into small (metabolically inactive) osteocy es enlarged (metabolically activated) osteocytes and empty lacunae. In rats (immobilizedfor' three weeks) with functioning parathyroid glands, but not after parathyroidectomy, the number of activated cells is markedly increased, whereas the number of small osteocytes is reduced. In animals with spinal cord severing the number of empty lacunae is also increased. Electron microscopical studies of undecalcified tibiae taken from rats immobilized for ten days showed a periosteocytic osteolysis with destruction of the lacunar wall, fragmentation of collagen fibres and loss of mineral crystals. The cytoplasmic seams of osteocytes were broadened, mitochondria were enlarged, and the cytoplasma showed vacuoles containing amorphous material which could be found in the pericellular space. Deep invaginations of the cytoplasma and an increase of the cell processes were typical findings. The results of the investigation point to an activation of osteocyte metabolism by immobilization. The osteocytes thus play an important part at the onset of immobilization osteoporosis. Periosteocytic osteolysis can be inhibited by parathyroidectomy. Therefore, the response of osteocytes to endogenous parathyroid hormone must be altered under conditions of immobilization.