Aging and matrix microdamage accumulation in human compact bone
Aging and matrix microdamage accumulation in human compact bone
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DOI：
10.1016/8756-3282(95)00370-3
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发表时间：
1995-12-01
期刊：
影响因子：
4.1
通讯作者：
Milgrom, C
中科院分区：
文献类型：
--
作者：
Schaffler, MB;Choi, K;Milgrom, C
骨基质中的骨基质微损伤，表现为微裂纹，在循环载荷下发生，体内载荷引起的微损伤已在人肋骨皮质中描述;然而，人类长骨皮质中微裂纹的存在和程度在很大程度上是未知的。采用组织形态计量学方法检测人类股骨密质骨标本中微裂纹的发生率和定位，我们发现股骨密质骨中存在的微损伤量随着年龄的增加而显著增加。最小二乘回归分析表明，在男性中，微裂纹密度（Cr，De，#/mm（2））随年龄呈指数增加（r（2）= 0.70）。在女性中，Cr.De.也随着年龄的增长而呈指数函数增加（r（2）= 0.79），其速率显著高于男性样本（p < 0.001），目前的研究表明，随着年龄的增长，骨微损伤的积累比内在过程对其修复的影响更快，材料性质的局部变化和组织感知和/或对微裂纹作出反应的能力的改变都可能在骨微损伤随老化的累积中起作用。骨中微损伤的这种累积将导致强度和刚度的降低，此外，对于理解衰老和骨脆性增加可能最重要的是，复合材料（如骨）中的基质微损伤将导致抗骨折能力的显著降低，讨论了随着年龄的增长，人类骨中基质微损伤的这种积累对衰老骨骼脆性增加的重要性，
Bone matrix microdamage in bone matrix, evidenced as microcracks, occurs consequent to cyclic loading, Microdamage caused by in vivo loading has been described in human rib cortex; however, the existence and extent of microcracks in human long bone cortices are largely unknown, Using histomorphometric methods to examine the incidence and localization of microcracks in human femoral compact bone specimens, we found that the amount of microdamage present in femoral compact bone increases dramatically with increasing age, Least squares regression analysis showed that in males, microcrack density (Cr,De,, #/mm(2)) increases exponentially with age (r(2) = 0.70). In females, Cr.De. also increases as an exponential function of increasing age (r(2) = 0.79), at a significantly higher rate than in male specimens (p < 0.001), The current studies indicate that with increasing age, bone microdamage accumulates more rapidly than intrinsic processes can effect its repair, A combination of cumulative loading history, focal changes in material properties and alteration in the ability of the tissue to perceive and/or react to microcracks may all play role in this accumulation of bone microdamage with aging, This accumulation of microdamage in bone will contribute to decreased strength and stiffness, In addition, and perhaps most significantly for understanding aging and increased bone fragility, matrix microdamage in composite materials like bone will result in a profoundly reduced resistance to fracture, The importance of this accumulation of matrix microdamage in human bone with increasing age in contributing to the increased fragility of the aging skeleton is discussed,