Bending properties, porosity, and ash fraction of black bear (Ursus americanus) cortical bone are not compromised with aging despite annual periods of disuse
Bending properties, porosity, and ash fraction of black bear (Ursus americanus) cortical bone are not compromised with aging despite annual periods of disuse
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DOI：
10.1016/j.jbiomech.2004.01.010
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发表时间：
2004-10-01
影响因子：
2.4
通讯作者：
Donahue, SW
中科院分区：
文献类型：
--
作者：
Harvey, KB;Donahue, SW
在包括人类在内的许多物种中，停用会导致骨骼重塑的失衡，从而导致骨吸收增加和骨形成减少，从而导致骨孔率增加。然而，黑熊(Ursus Americanus)可能不会像其他动物那样，在长期不使用(即冬眠)期间出现废用性骨量减少，因为它们在冬眠期间保持成骨细胞骨形成，即使在冬眠期间骨吸收增加。黑熊还可能有一种机制，可以在它们的再活动期间迅速而完全地恢复丢失的骨骼(通过冬眠期间增加的吸收)。我们的研究结果表明，尽管黑熊每年都会停用，但皮质骨的弯曲强度(211328兆帕)、弯曲模数(16.029.5兆帕)、断裂能(0.0118-0.0205 J mm(-2))、孔隙率(2.3-7.1%)和灰分(0.638-0.672)不会随着年龄的增长而受损。事实上，皮质骨的极限强度(p=0.01)、弹性系数(p=0.04)和灰分(p=0.03)显示随着年龄的增长(2-14岁)显著增加。雌性熊在冬眠期间生育和哺乳；然而，我们发现雄性和雌性之间没有显著的骨骼特性差异(p>；0.16)。其他动物需要比固定时间长2-3倍的再动员时间才能恢复在废弃过程中丢失的骨骼。我们的发现支持这样一种观点，即每年冬眠5-7个月的黑熊已经进化出一种生物学机制来减轻废弃对骨骼多孔性和机械行为的不利影响。(C)2004爱思唯尔有限公司。保留所有权利。
In many species, including humans, disuse causes an imbalance in bone remodeling that leads to increased bone porosity as a result of increased bone resorption and decreased bone formation. However, black bears (Ursus americanus) may not develop disuse osteopenia, to the extent that other animals do, during long periods of disuse (i.e. hibernation) because they maintain osteoblastic bone formation during hibernation, even though bone resorption is increased during hibernation. Black bears may also have a mechanism to rapidly and completely recover the bone lost (by increased resorption during hibernation) during their remobilization period. Our findings suggest that cortical bone bending strength (211-328 MPa), bending modulus (16.0-29.5 MPa), fracture energy (0.0118-0.0205 J mm(-2)), porosity (2.3-7.1%), and ash fraction (0.638-0.672) are not compromised with age in black bears, despite annual periods of disuse. In fact, the ultimate strength (p = 0.01), modulus (p = 0.04), and ash fraction (p = 0.03) of cortical bone were shown to significantly increase with age (2-14 yrs). Female bears give birth and nurse during hibernation; however, we found no significant (p > 0.16) differences between male and female bone properties. Other animals require remobilization periods 2-3 times longer than the immobilization period to recover the bone lost during disuse. Our findings support the idea that black bears, which hibernate 5-7 months annually, have evolved a biological mechanism to mitigate the adverse effects of disuse on bone porosity and mechanical behavior. (C) 2004 Elsevier Ltd. All rights reserved.