Simske S J, Luttges M W, Wachtel H
Dept. of Electrical Engineering, University of Colorado, Boulder 80309-0425.
Biomed Sci Instrum. 1990;26:87-94.
The microgravity, or weightlessness, of space causes measurable bone deterioration in humans and rats. The use of tail-suspension to simulate weightlessness in rats is well-documented. Our studies have focused on mice, as their smaller size suggests more efficient space-based experimentation. Using mice ranging from 1.3-12 months in age, the results of a 2-wk suspension were ascertained through measurement of bone mass and mechanical (3-pt bending) characteristics. Significant differences between tail-suspended (S) and control (C) mice were noted for mice less than 6 months old. Such significance was not observed for the older mice. In addition, for the 1.3 month and 1.7 month old mice, a group of mice were sacrificed (designated PC, or pre-control) with ages matching those of the S mice prior to suspension. These were assayed to determine if the effects of tail-suspension are predominantly on growth-suppression or on bone atrophy. Our results show that tail-suspension effects are best explained by growth-suppression, as both the C and S groups showed growth when compared to the PC groups. 4-wk tail-suspensions of 10 month old mice were implemented to determine if increased suspension time would produce deterioration in older mice. An indication of longer periods of suspension being effective was found, but significant differences like those obtained for younger mice were not seen in the numbers of mice used.
太空的微重力或失重状态会导致人类和大鼠出现可测量的骨质流失。利用尾部悬吊来模拟大鼠失重状态的做法已有充分记载。我们的研究聚焦于小鼠，因为其体型较小意味着太空实验效率更高。使用年龄在1.3至12个月之间的小鼠，通过测量骨量和力学（三点弯曲）特性来确定为期2周悬吊的结果。对于小于6个月龄的小鼠，尾部悬吊（S）组和对照组（C）之间存在显著差异。而对于年龄较大的小鼠，未观察到这种显著性差异。此外，对于1.3个月龄和1.7个月龄的小鼠，在悬吊前处死了一组年龄与S组小鼠匹配的小鼠（称为PC，即预对照组）。对这些小鼠进行检测，以确定尾部悬吊的影响主要是生长抑制还是骨质萎缩。我们的结果表明，尾部悬吊的影响最好用生长抑制来解释，因为与PC组相比，C组和S组均显示出了生长。对10个月龄小鼠进行了为期4周的尾部悬吊，以确定延长悬吊时间是否会使老年小鼠出现骨质退化。结果发现有迹象表明较长时间的悬吊是有效的，但在所使用的小鼠数量上未观察到与年轻小鼠类似的显著差异。
