SUPPRESSION OF THE OSTEOGENIC RESPONSE IN THE AGING SKELETON
SUPPRESSION OF THE OSTEOGENIC RESPONSE IN THE AGING SKELETON
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DOI：
10.1007/bf00301627
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发表时间：
1992-04-01
影响因子：
4.2
通讯作者：
MCLEOD, KJ
中科院分区：
文献类型：
--
作者：
RUBIN, CT;BAIN, SD;MCLEOD, KJ
在年轻的成人骨骼中，物理刺激被证明是有效的成骨能力，评估其在老化骨骼中刺激新骨形成的能力。使用外部可加载的、功能隔离的火鸡尺骨制剂，对1岁(n=5)和3岁(n=3)火鸡的尺骨进行每天300个循环的加载方案，产生高但生理水平的正常应变(3,000微应变)。加载8周后，对实验和完整对照尺骨进行面积特性和组织形态计量学检查。与完整的对侧对照尺骨相比，1岁动物的骨横截面积增加了30.2%(+/-7.8%)，而老年骨骼的面积特性基本保持不变(-3.3+/-7.5%)。1岁实验动物尺骨的新骨形成以骨膜骨结合激活(4.0+/-0.4-mU/天)为特征。相比之下，在3岁的雄性中，只有1只动物的骨膜骨形成被激活，而且这种激活程度显著减弱(不到0.8微米/天)。皮质内骨重建的组织形态计量学评估显示，在这两个年龄组中，对照尺骨和实验尺骨之间没有显著差异。然而，在3岁的男性中，骨单位平均壁厚和骨形成西格玛显著增加(P<；0.05)。总而言之，这些数据表明，在年轻的成年人骨骼中明显是成骨的物理信号在老年骨组织中很难被识别。目前尚不清楚这是否意味着骨细胞群体感知这些物理信号的能力恶化，还是它们的反应能力失败。
The ability of physical stimuli demonstrated as potently osteogenic in the young adult skeleton were evaluated for their capacity to stimulate new bone formation in the aging skeleton. Using the externally loadable, functionally isolated turkey ulna preparation, the ulnae of 1-year-old (n = 5), and 3-year-old (n = 3) turkeys were subjected to 300 cycles per day of a load regimen generating a high but physiologic level of normal strain (3,000 microstrain). Following 8 weeks of loading, areal properties and histomorphometry were performed on both the experimental and intact control ulnae. Bone cross-sectional areas in the 1-year-old animal increased by 30.2% (+/- 7.8%) as compared with the intact contralateral control ulnae, whereas the areal properties of the older skeleton remained essentially unchanged (- 3.3 +/- 7.5%). Renewed bone formation in the experimental ulnae of the 1-year-old animals was characterized by the activation of periosteal bone apposition (4.0 +/- 0.4-mu-m/day). In comparison, periosteal bone formation in the 3-year-old males was activated in only 1 animal, and this at a significantly attenuated level (less than 0.8-mu-m/day). The histomorphometric evaluation of intracortical bone remodeling revealed no significant differences between the control and experimental ulnae in either age group. However, osteon mean wall thickness and bone formation sigma were significantly increased in the 3-year-old males (P < 0.05). In conclusion, these data suggest that a physical signal that is clearly osteogenic in the young adult skeleton is hardly acknowledged in older bone tissue. Whether this represents a deterioration of the bone cell population's ability to perceive these physical signals or a failure of their capacity to respond is not yet clear.