Vico L, Alexandre C
Laboratoire de Biologie du Tissu Osseux, Gip Exercise, Faculté de Médecine Jacques Lisfranc, Saint-Etienne, France.
J Bone Miner Res. 1992 Dec;7 Suppl 2:S445-7. doi: 10.1002/jbmr.5650071415.
Our knowledge of the adaptation of human bone microgravity remains poor despite long-term Russian spaceflights and the recent use of accurate techniques for bone mass measurements. The extent of bone deficits in the adaptation of the whole skeleton is not clear. At the tissue level, bone resorption and formation activities have been studied only in bones from rats after spaceflights lasting a few days to 3 weeks. In these animals, architectural features consistent with osteoporosis have been found in the proximal tibia. In pregnant animals the osteoclast population is increased at other skeletal sites. In areas of weight-bearing bones that are not protected by muscular insertions, bone resorption is not markedly altered after 7 days of spaceflight and bone formation is reduced. In areas of weight-bearing bones with muscular insertions and in non-weight-bearing bones, similar changes in bone cell activity are delayed. The severity of the response seems to vary with the location of the bone in the skeleton and its initial level of bone turnover. After 12.5 days the acute bone changes are less and no additional changes are observed after 21 days in space. We conclude that generalized bone deficits do not appear to be a consequence of microgravity but occur in localized areas according to the level of modeling and remodeling and of the support function of each bone at 1 g.
尽管俄罗斯进行了长期太空飞行，且近期采用了精确的骨量测量技术，但我们对人体骨骼在微重力环境下的适应性了解仍然有限。整个骨骼在适应过程中骨量缺失的程度尚不清楚。在组织层面，仅对太空飞行持续数天至3周的大鼠骨骼进行了骨吸收和形成活动的研究。在这些动物中，胫骨近端发现了与骨质疏松症一致的结构特征。在怀孕动物中，其他骨骼部位的破骨细胞数量增加。在未受肌肉附着保护的负重骨区域，太空飞行7天后骨吸收没有明显改变，但骨形成减少。在有肌肉附着的负重骨区域和非负重骨中，骨细胞活动的类似变化出现延迟。反应的严重程度似乎因骨骼中骨骼的位置及其初始骨转换水平而异。12.5天后急性骨变化较小，太空飞行21天后未观察到其他变化。我们得出结论，全身性骨量缺失似乎不是微重力的结果，而是根据每块骨骼在1g重力下的建模和重塑水平以及支撑功能，在局部区域发生。
