生長期大白鼠骨骼對機械負重的適應性 : 組織形態學研究

ADAPTATION OF BONE TO MECHANICAL LOADING IN THE GROWING RAT: HISTOMORPHOMETRIC STUDY

李大中(Ta-Chung Lee) ； 劉榮泰(Yun-Tai Lu) ； 王天美(Teen-Meei Wang)

《中華民國復健醫學會雜誌》 24卷2期 (1996/12) Pp. 120-131

摘要

以坐骨神經切除法固定六週大雄性大白鼠右後肢達成右後肢未負重，並做為觀察體，觀察其0,4,6,8,12及24週後的鬆質骨與皮質骨量的變化。動物於固定期間給予骨螢光劑雙重標識，且於近側脛骨幹?端和脛骨幹取20μm厚非脫鈣標本片做為靜態與動態組織型態計量。
固定引發未負重肢鬆質與皮質骨量的流失。未負重肢引起骨吸收的增加及骨生成的減少，導致負向鬆質骨平衡。此未負重的效應乃經由抑制造骨細胞的數目與活性，及加速骨髓腔的擴大。侵蝕與標誌表面的減少見於各不同固定期間。此等組織形態計量的變化，意謂鬆質骨量的增加，乃由於增加骨生成的活性與減少骨再塑的空間。雖然皮質骨量變化不大，但外骨膜生成活性的確增加。
本實驗的結果顯示大白鼠骨骼能快速的適應機械使用。而單肢固定模式適於用來研究廢用性骨骼對機械負載肢之結構適應性之機轉。

關鍵字

骨組織狀態計測法 ； 骨塑造 ； 骨重塑

並列摘要

Six-week-old male rats were subjected to right hindlimb immobilization or served as control for 0,4, 6, 8,12, or 24 weeks. There were double-labeled with bone markers prior to sacrifice. The right limb was immobi-lized by sciatic nerve denervation and considered unloaded. Static and dynamic histomorphometry were performed on 20- urn-thick Villanueva stained, undecalcified sections of the proximal tibial metaphysis and thetibial shaft.
In the unloaded limb, immobilization induced cancellous and cortical bone loss. Unloading caused a negative trabecular bone balance from a combination of elevated bone resorption and depressed bone formation. The bone loss was accompanied by poorer trabecular architecture(trabacular number decreased and trabecular separation increased).Unloading shut off nearly all periosteal bone formation and accelerated bone marrow expansion. The effects of unloading appeared to be mediated by recruiting fewer osteoblasts which showed inhibitedactivity, these histological changes lowered cortical bone mass by inhibiting diaphyseal cross sectional expansion and enlarging the bone marrow cavity.
These findings indicate that the rat skeleton can quickly adapt to mechanical usage. Therefore, the one-legged immobilization model can be useful in studies of the mechanism of structural adaptation to mechanicalusage.

並列關鍵字

histomorphometry ； modeling ； remodeling