Ijiri K, Ma Y F, Jee W S, Akamine T, Liang X
Radiobiology Division, University of Utah, Salt Lake City 84112, USA.
Bone. 1995 Oct;17(4 Suppl):207S-212S. doi: 10.1016/8756-3282(95)00293-m.
No data exit for distal tibia (DT), a bone site with growth plate closure at 3 months of age and with very low trabecular bone turnover rate. The purpose of this study was to characterize the response of DT to aging and immobilization (IM) in 6 to 16.5 month-old female rats. One hundred and forty six 6 month-old Sprague-Dawley rats were divided into aging controls and right hindlimb immobilization (RHLI) groups. The right hindlimb was immobilized against the abdomen with elastic bandages. Rats were sacrificed serially from 6 to 16.5 months old at intervals of 2 to 8 weeks. The histomorphometric study was performed on areas of former epiphyseal and metaphyseal trabecular bone of DT. No changes on bone mass or architecture were found in aging controls throughout the study. There was a decrease in bone mass of the former epiphysis after 3.5 months of IM due to resorption exceeding formation. Then it reverted to the aging control level at 4 months post IM. At the former metaphyseal site, significant bone loss (-19%) was observed as early as two weeks after IM. The peak bone loss (-54%) was reached at 1.5 months after IM and plateaued thereafter. The bone loss was mainly due to the reduction of trabecular thickness although trabecular number decreased significantly after 3.5 months IM. These results suggest that both former epiphysis and metaphyseal trabecular bones in DT can quickly adapt by losing bone to immobilization.
胫骨远端（DT）没有相关数据，该骨部位在3月龄时生长板闭合，小梁骨转换率极低。本研究的目的是描述6至16.5月龄雌性大鼠DT对衰老和固定（IM）的反应。146只6月龄的Sprague-Dawley大鼠被分为衰老对照组和右后肢固定（RHLI）组。右后肢用弹性绷带固定于腹部。大鼠在6至16.5月龄期间，每隔2至8周分批处死。对DT的原骨骺和干骺端小梁骨区域进行组织形态计量学研究。在整个研究过程中，衰老对照组的骨量和骨结构没有变化。IM 3.5个月后，由于吸收超过形成，原骨骺的骨量减少。然后在IM后4个月恢复到衰老对照组水平。在原干骺端部位，IM后两周就观察到明显的骨质流失（-19%）。IM后1.5个月达到最大骨量流失（-54%），此后趋于平稳。骨量流失主要是由于小梁厚度的减少，尽管IM 3.5个月后小梁数量也显著减少。这些结果表明，DT的原骨骺和干骺端小梁骨都可以通过骨质流失快速适应固定。
