不对称力学负荷对大鼠椎体骨微结构的影响

Scoliosis model in an asymmetric force bipedal rat and bone micro-architecture adaptations of ver?鄄tebrae

中文关键词:  脊柱侧凸  双足大鼠  不对称力  骨微结构

英文关键词:Scoliosis  Bipedal rat  Asymmetric load  Bone micro-architecture

中文摘要:

  【摘要】 目的：探讨不对称力学负荷对大鼠椎体骨小梁微结构形态学参数的影响。方法：40只SD大鼠随机分为双足鼠组和拴系-双足鼠组。通过截去双前肢和尾巴建立双足大鼠模型；拴系-双足鼠组在其基础上，利用丝线拴系左侧肩胛下角与同侧骨盆髂骨翼，完成造模。术后第8周末将拴系缝线剪断。观察12周，每间隔4周摄脊柱全长正位X线片，观察各组大鼠侧凸发生情况；术后12周处死大鼠，测量顶椎旋转度，获取顶椎（拴系-双足鼠组）或L1椎体（双足鼠组）行显微CT扫描，观察椎体骨微结构变化情况。结果：双足鼠组中无脊柱侧凸发生，拴系-双足鼠组大鼠均发生侧凸，顶椎均位于T12或L1，其术后Cobb角为0°，术后4周时为23.5°±4.2°（16°～31°），术后8周时为40.6°±9.4°（28°～63°），三个观察点之间的结果比较均有显著性差异（P<0.05）。术后12周时Cobb角为37.8°±9.9°（26°～50°），与术后8周比较无显著性差异（P>0.05）。顶椎旋转度为6.0°±2.2°（63.5°～9.0°）。双足鼠组两侧各个参数之间均无显著性差异（P>0.05）。拴系-双足鼠组大鼠顶椎的凹侧体积骨密度（volumet?鄄ric bone mineral density，vBMD）、骨体积分数（bone volume fraction，bone volume/total volume，BV/TV）、骨小梁厚度（trabecular thichness，Tb.Th）数值明显高于凸侧，骨小梁间隔（trabecular separation，Th.Sp）数值显著低于凸侧，而骨小梁数量（trabecular number，Tb.N）无显著性差异（P>0.05）。拴系-双足鼠组的凸侧BMD及凹侧vB?鄄MD、BV/TV、Tb.Th数值显著高于双足鼠组，凹侧Tb.Sp也显著小于双足鼠组。结论：4周龄双足SD大鼠通过8周的拴系即可形成Cobb角>10°的稳定的结构性侧凸畸形。脊柱侧凸时，骨骼的重建能力提高了凹侧骨骼强度，从而在某种程度上阻止了侧凸畸形的进展。

英文摘要:

  【Abstract】 Objectives: To investigate the effects of the asymmetrical loading on the rat vertebral bone structure of morphological parameters of trabecula bone. Methods: 40 SD rats were divided into 2 groups: bipedal rat group and tether-bipedal rat group. Bipedal rat model was made by amputation of the forelimbs and tail. The left inferior angle of scapula to the ipsilateral bony pelvis was sutured in tether-bipedal rat group after amputation of the forelimbs and tail. After 8 weeks, the tethering suture was released. Spinal deformity was documented by serial X-ray examinations at an interval of 4 weeks. After sacrifice, the rotation angle of apical vertebra was measured and Micro CT was used to analyze the bone micro-architecture. Results: All rats in tether-bipedal rat group developed scoliosis and no scoliosis was detected in bipedal rat group. The average initial Cobb angle was 0° immediately after the operation and progressed to an average of 23.5°±4.2°(16°-31°) after 4 weeks, 40.6°±9.4°(28°－63°) after 8 weeks, 37.8°±9.9°(26°－50°) after 12 weeks. The average rotation angle of apical vertebra was 6.0°±2.2°(3.5°-9.0°). There was no difference in vBMD, BV/TV, Tb.Th, Tb.N or Tb.Sp between both sides of vertebra in bipedal rat group. The vBMD, BV/TV and Tb.Th on the concave side significantly increased, and Tb.Sp significantly decreased compared with that on the convex side in tether-bipedal rat group. The vBMD, BV/TV and Tb.Th on the concave side and vBMD on the convex side in tether-bipedal rat group significantly increased compared with those of the bipedal rat group. Conclusions: Suturing the left inferior angle of scapula to the ipslateral bony pelvis in bipedal rats can establish the scoliosis model successfully. Bone micro-architecture on the concave side of apical vertebra is remodeling, which can help to prevent the progress of scoliosis.