Sakai A, Nakamura T, Tsurukami H, Okazaki R, Nishida S, Tanaka Y, Norimura T, Suzuki K
Department of Orthopedic Surgery, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
Bone. 1996 May;18(5):479-86. doi: 10.1016/8756-3282(96)00042-7.
Trabecular bone turnover and bone marrow capacity for the development of bone cells in the tibia were assessed after sciatic neurectomy (NX) in mice. The right hindlimbs of 6-week-old DDY mice were neurectomized and left hindlimbs were sham-operated and served as NX controls. Histomorphometrical analyses of the trabecular bone of the proximal tibia demonstrated the initial decrease in bone formation rate for the first 14 days and the subsequent increase in osteoclast surface for the next 14 days. The number of adherent stromal cells per tibia obtained for the NX limbs was reduced on days 7 and 10 postsurgically, and then recovered on day 12. However, the alkaline phosphatase activity of the cells was persistently depressed. The formation of osteoclast-like multinucleated cells in the marrow cultures obtained from NX limbs at days 10, 12, and 14 showed a significant increase in the medium containing parathyroid hormone (PTH). The number of colonies cultured for colony forming units-fibroblastic (CFU-f) that developed from the marrow cells did not differ in the NX and the contralateral limbs at any time during the period. On the other hand, the number of colonies cultured of colony forming units for granulocytes and macrophages (CFU-GM) was markedly increased for both the NX and the contralateral tibiae at days 12 and 14. This study clearly demonstrates that there are two stages in the development of osteopenia after NX. During the first 14 days, trabecular bone formation and number of marrow stromal cells are reduced. In the second 14 day period, the trabecular osteoclast number is increased and osteoclast formation from the bone marrow cells is enhanced in the presence of PTH. However, neither the CFU-f nor the CFU-GM assay could identify the changes in osteogenic or osteoclastogenic potential of the bone marrow. These in vitro assays provide limited information on the shifts in bone marrow cell lineages and the local environment producing osteopenia in the immobilized limb in vivo.
在小鼠坐骨神经切断术（NX）后，评估胫骨小梁骨转换和骨髓中骨细胞发育的能力。将6周龄DDY小鼠的右后肢进行神经切断，左后肢进行假手术并作为NX对照。对近端胫骨小梁骨的组织形态计量学分析表明，最初14天骨形成率下降，随后14天破骨细胞表面增加。手术后第7天和第10天，NX肢体每胫骨的黏附基质细胞数量减少，然后在第12天恢复。然而，细胞的碱性磷酸酶活性持续降低。在含有甲状旁腺激素（PTH）的培养基中，从NX肢体在第10、12和14天获得的骨髓培养物中破骨细胞样多核细胞的形成显著增加。在此期间的任何时候，从骨髓细胞发育而来的集落形成单位-成纤维细胞（CFU-f）培养的集落数量在NX和对侧肢体中没有差异。另一方面，在第12天和第14天，NX和对侧胫骨的粒细胞和巨噬细胞集落形成单位（CFU-GM）培养的集落数量均显著增加。本研究清楚地表明，NX后骨质减少的发展有两个阶段。在最初的14天内，小梁骨形成和骨髓基质细胞数量减少。在第二个14天期间，小梁破骨细胞数量增加，并且在PTH存在下骨髓细胞的破骨细胞形成增强。然而，CFU-f和CFU-GM测定均无法识别骨髓成骨或破骨潜能的变化。这些体外测定提供了关于体内固定肢体中骨髓细胞谱系变化和产生骨质减少的局部环境的有限信息。
