Wronski T J, Morey-Holton E R
Aviat Space Environ Med. 1987 Jan;58(1):63-8.
The skeletal response to simulated weightlessness was studied in rats subjected to two different methods of suspension. Skeletal unloading of the hind limbs for a two week period was achieved by use of either a back harness or tail traction. In comparison to pair-fed control rats, back-suspended rats failed to gain weight whereas tail-suspended rats exhibited normal weight gain. Quantitative bone histomorphometry revealed marked skeletal abnormalities in the proximal tibial metaphysis of back-suspended rats. Loss of trabecular bone mass in these animals was due to a combination of depressed longitudinal bone growth, decreased bone formation, and increased bone resorption. In contrast, the proximal tibia of tail-suspended rats was relatively normal by these histologic criteria. However, a significant reduction in trabecular bone volume occurred during 2 weeks of tail suspension, possibly due to a transient inhibition of bone formation during the early stages of skeletal unloading. Lack of weight gain in back-suspended rats may be indicative of a pronounced stress response during which corticosteroids adversely affected the skeleton. Maintenance of normal weight gain by tail-suspended rats provides evidence for the less traumatic nature of this method of suspension. Our findings indicate that tail suspension may be a more appropriate model for evaluating the effects of simulated weightlessness on skeletal homeostasis.
在通过两种不同悬吊方法处理的大鼠中研究了骨骼对模拟失重的反应。使用背部吊带或尾部牵引实现后肢骨骼卸载两周。与成对喂养的对照大鼠相比，背部悬吊的大鼠体重未增加，而尾部悬吊的大鼠体重正常增加。定量骨组织形态计量学显示，背部悬吊大鼠胫骨近端干骺端存在明显的骨骼异常。这些动物小梁骨量的减少是由于纵向骨生长受抑、骨形成减少和骨吸收增加共同作用的结果。相比之下，根据这些组织学标准，尾部悬吊大鼠的胫骨近端相对正常。然而，在尾部悬吊2周期间，小梁骨体积显著减少，这可能是由于骨骼卸载早期骨形成受到短暂抑制所致。背部悬吊大鼠体重不增加可能表明存在明显的应激反应，在此期间皮质类固醇对骨骼产生了不利影响。尾部悬吊大鼠维持正常体重增加证明了这种悬吊方法创伤性较小。我们的研究结果表明，尾部悬吊可能是评估模拟失重对骨骼稳态影响的更合适模型。
