RECOVERY FROM DISUSE OSTEOPENIA COINCIDENT TO RESTORATION OF MUSCLE STRENGTH IN MDX MICE
RECOVERY FROM DISUSE OSTEOPENIA COINCIDENT TO RESTORATION OF MUSCLE STRENGTH IN MDX MICE
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DOI：
10.1016/8756-3282(93)90084-n
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发表时间：
1993-07-01
期刊：
影响因子：
4.1
通讯作者：
JOHNSON, RB
中科院分区：
文献类型：
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作者：
ANDERSON, JE;LENTZ, DL;JOHNSON, RB
这项研究的目的是比较MDX小鼠(表现为X连锁肌肉营养不良和随后的肌肉再生)和年龄匹配的对照组小鼠在肌肉无力和恢复后胫骨的结构和强度。然后，可以确定肌肉无力和恢复正常肌肉力量后恢复所造成的废用性萎缩的程度。与年龄匹配的对照组相比，4周龄的mdx小鼠胫骨与虚弱的胫前肌相邻的胫骨的X射线密度(p<；0.001)和皮质厚度(p<；0.001)显著降低，孔隙率(p<；0.001)增加，提示有废用性骨量减少的发展。与年龄匹配的对照胫骨相比，折断MDX胫骨所需的力量显著减少(p<；0.05)。此外，夏佩的纤维密度降低(P<；0.001)，表明胫骨前肌与骨的附着性减弱。在12周时，在肌肉再生期间，MDX胫骨皮质厚度(p<；0.001)和孔隙率(p<；0.01)仍然显著低于年龄匹配的对照组，但钙含量和夏培氏纤维密度和X线片密度显著高于年龄匹配的对照组(p<；0.001)，这表明随着附着的肌肉力量的恢复，骨矿化和肌肉附着强度已增加到高于正常水平。到18周时，MDX胫骨横截面积、皮质厚度和孔隙率仍显著低于正常(p<；0.001)。尽管在18周时，夏佩的纤维密度高于年龄匹配的对照组(P<；0.001)，但12周龄的MDX动物的胫骨钙含量(P<；0.005)和夏佩的纤维密度(P<；0.001)显著低于对照组。在18周龄时，MDX组的胫骨在骨折前的变形显著低于对照组，这表明胫骨是脆性的。因此，在MDX肌肉附着到骨质疏松的骨的部位，伴随着肌肉力量恢复的重塑是不典型的，并且产生比功能所需更大的附着力量。这些观察表明，关于废用性骨量减少、DMD和其他神经肌肉疾病患者的骨量和肌肉-骨附着的数据是必要的。
The objective of this study was to compare the tibial structure and the strength of the tibia during muscle weakness and after recovery in mdx mice (which demonstrate X-linked muscular dystrophy and subsequent muscle regeneration) and age-matched control mice. The extent of disuse atrophy produced by muscle weakness and recovery following restoration of normal muscle strength could then be determined. The tibiae adjacent to weakened tibialis anterior muscles of 4-week-old mdx mice had significantly reduced radiographic density (p < 0.05) and cortical thickness (p < 0.001), and increased porosity (p < 0.001) compared to age-matched controls, suggesting development of disuse osteopenia. Significantly less force was required to break mdx tibiae than age-matched control tibiae (p < 0.05). In addition, Sharpey's fiber density was reduced (p < 0.001), suggesting a weakened attachment of the tibialis anterior muscle to bone. At 12 weeks, during the period of muscle regeneration, mdx tibial cortical thickness (p < 0.001) and porosity (p < 0.01) remained significantly lower, but percent calcium and Sharpey's fiber and radiographic densities were significantly greater (p < 0.001) than in age-matched controls, suggesting that bone mineralization and muscle attachment strength had increased to above normal levels in parallel with recovery of strength by the attached muscle. By 18 weeks, mdx tibial cross-sectional area, cortical thickness, and porosity remained significantly less (p < 0.001) than normal. Although Sharpey's fiber density was greater than in age-matched controls (p < 0.001) by 18 weeks, mdx tibial percent calcium (p < 0.005) and Sharpey's fiber density (p < 0.001) were significantly reduced from levels in 12-week-old mdx animals. There was significantly less deformation of the tibia prior to fracture in mdx than control tibiae at 18 weeks of age, suggesting tibial brittleness. Thus, at the site of attachment of mdx muscle to osteopenic bone, the remodelling which accompanies recovery of muscle strength is atypical, and produces an attachment of greater strength than function appears to require. These observations suggest that data are needed regarding bone mass and muscle-bone attachments in humans with disuse osteopenia, DMD, and other neuromuscular diseases.