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Differential effects between the loss of MMP-2 and MMP-9 on structural and tissue-level properties of bone

热2 Dr.LinZhen 添加于 2011-1-5 09:23 | 2272 次阅读 | 3 个评论

作者
Nyman JS, Lynch CC, Perrien DS, Thiolloy S, O'Quinn EC, Patil CA, Bi X, Pharr GM, Mahadevan-Jansen A, Mundy GR
摘要
Matrix metalloproteinases (MMPs) are capable of processing certain components of bone tissue including type 1 collagen, a determinant of the biomechanical properties of bone tissue, and they are expressed by osteoclasts and osteoblasts. Therefore, we posit that MMP activity can affect the ability of bone to resist fracture. To explore this possibility, we determined the architectural, compositional, and biomechanical properties of bones from wild-type (WT), Mmp2(-/-), and Mmp9(-/-) female mice at 16 weeks of age. MMP-2 and MMP-9 have similar substrates, but are primarily expressed by osteoblasts and osteoclasts, respectively. Analysis of the trabecular compartment of the tibia metaphysis by micro-computed tomography (microCT) revealed that these MMPs influence trabecular architecture, not volume. Interestingly, the loss of MMP-9 improved the connectivity density of the trabeculae, whereas the loss of MMP-2 reduced this parameter. Similar differential effects in architecture were observed in the L5 vertebra, but bone volume fraction was lower for both Mmp2(-/-) and Mmp9(-/-) mice than for WT. The mineralization density and mineral-to-collagen ratio, as determined by microCT and Raman microspectroscopy, were lower in the Mmp2-/- bones compared to WT controls. Whole bone strength, as determined by three point bending or compression testing, and tissue-level modulus and hardness, as determined by nanoindentation, were less for Mmp2-/- than for WT bones. In contrast, the Mmp9-/- femurs were less tough with lower post-yield deflection (more brittle) than that of the WT femurs. Taken together, MMPs play a complex role in maintaining bone integrity with the cell type that expresses the MMP likely being a contributing factor to how the enzyme affects bone quality. (c) 2010 American Society for Bone and Mineral Research.
详细资料
- 文献种类:期刊
- 期刊名称: Journal of Bone and Mineral Research : the Official Journal of the American Society for Bone and Mineral Research
- 期刊缩写: J Bone Miner Res
- 期卷页: 2010年
- 地址: Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN
- ISBN: 0884-0431
标签

MMP
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