32 wk old C3H/HeJ mice actively respond to mechanical loading
32 wk old C3H/HeJ mice actively respond to mechanical loading
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DOI：
10.1016/j.bone.2007.12.222
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发表时间：
2008-04-01
期刊：
影响因子：
4.1
通讯作者：
Gross, Ted S.
中科院分区：
文献类型：
--
作者：
Poliachik, Sandra L.;Threet, DeWayne;Gross, Ted S.
许多研究表明，与C57 BL/6 J（C57）小鼠相比，C3 H/HeJ（C3 H）小鼠对机械负荷有轻度反应。根据16周C3 H小鼠高基线骨膜成骨细胞活性的数据，我们推测，简单地让C3 H小鼠老化，直到基底骨膜骨形成相当于16周C57小鼠，将恢复C3 H小鼠的机械反应性。我们通过使32周龄的C3 H小鼠和16周龄的C57小鼠的右胫骨经受低强度的静息插入负荷（峰值应变：1235 μ m），然后使32周龄的C3 H小鼠的右胫骨经受低（1085 μ m）或中等（1875 μ m）强度的循环负荷来检验这一假设。通过动态组织形态计量学评价成骨细胞对皮质内和骨膜表面负荷的反应。在32周龄时，C3 H小鼠对低强度静息插入负荷的反应与未负荷对侧骨相比，骨膜矿化表面、矿物质沉积率和骨形成显著升高。令人惊讶的是，在C3 H小鼠中通过低幅度的休息插入负荷诱导的骨膜骨形成超过了在16周C57小鼠中诱导的骨膜骨形成。在32周龄时，C3 H小鼠也表现出对增加的循环负荷幅度的反应升高。我们的结论是，高水平的基础成骨细胞的功能在16周C3 H小鼠似乎压倒了组织的能力，否则合成代谢的机械负荷刺激。然而，当基底表面成骨细胞活性相当于16周C57小鼠，C3 H小鼠表现出明确的能力，无论是休息插入或循环负荷。(c)2008年爱思唯尔公司All rights reserved.
Numerous studies indicate that C3H/HeJ (C3H) mice are mildly responsive to mechanical loading compared to C57BL/6J (C57) mice. Guided by data indicating high baseline periosteal osteoblast activity in 16 wk C3H mice, we speculated that simply allowing the C3H mice to age until basal periosteal bone formation was equivalent to that of 16 wk C57 mice would restore mechanoresponsiveness in C3H mice. We tested this hypothesis by subjecting the right tibiae of 32 wk old C3H mice and 16 wk old C57 mice to low magnitude rest-inserted loading (peak strain: 1235 lie) and then exposing the right tibiae of 32 wk C3H mice to low (1085 mu e) or moderate (1875 mu epsilon) magnitude cyclic loading. The osteoblastic response to loading on the endocortical and periosteal surfaces was evaluated via dynamic histomorphometry. At 32 wk of age, C3H mice responded to low magnitude rest-inserted loading with significantly elevated periosteal mineralizing surface, mineral apposition rate and bone formation compared to unloaded contralateral bones. Surprisingly, the periosteal bone formation induced by low magnitude rest-inserted loading in C3H mice exceeded that induced in 16 wk C57 mice. At 32 wk of age, C3H mice also demonstrated an elevated response to increased magnitudes of cyclic loading. We conclude that a high level of basal osteoblast function in 16 wk C3H mice appears to overwhelm the ability of the tissue to respond to an otherwise anabolic mechanical loading stimulus. However, when basal surface osteoblast activity is equivalent to that of 16 wk C57 mice, C3H mice demonstrate a clear ability to respond to either rest-inserted or cyclic loading. (c) 2008 Elsevier Inc. All rights reserved.