脊髓损伤继发骨质疏松大鼠后肢骨质量变化

目的：探讨脊髓损伤对大鼠后肢骨质量的影响，揭示SCI继发骨质疏松特点。方法：60只SD大鼠按体重随机分为6组．对20只采用脊髓横断法在第10胸椎处横断脊髓制作完全性SCI模型，分为SCI6周和12周组；20只在同水平处切断棘突、椎板制作似手术对照组（sham），分为Sham6周和12周组；另20只分为正常6周和12周对照组。分别在脊髓损伤后6周和12周时取材，进行股骨生物力学性能和胫骨上端骨形态计量学测试。结果：脊髓损伤6周时，大鼠胫骨E端骨小梁厚度、骨小梁面积百分比明显降低（P〈0.01、P〈0．05），单位面积破骨细胞数明显增加（P〈0．05）：股骨中段最大载荷明显降低（P＜0．05）。脊髓损伤12周时，除上述改变外，胫骨上端骨体积百分比也明显降低（P〈0．05）：股骨最大载荷进一步降低（P＜0．001），结构刚度也明显下降（P〈0．05）。其他指标无明显改变（P〉0．05）。结论：脊髓损伤6周时，大鼠后肢骨已出现损害，12周时，其损害进一步加重。

The influence of spinal cord injury on hinder limb bone histomorphometric and biomechanical characterization in SD rats

Objective:To determine the change of hinder limb bone histomorphometric and biomechanical characterization in rats with spinal cord injury(SCI). Method:Sixty SD rats were randomly divided into control group(40 cases) and experiment group(20 cases). The rats of experiment group were transected at the tenth thoracic vertebra to make models of SCI, and control group included normal control group and sham operation group in which the rats were undergone a sham procedure. At SCI 6th and 12th weeks, the hinder limb bone histomorphometric and biomechanical characterization were tested respectively with analysis techniques of histomorphometric data and femur three point bending test. Result: Compared with the control group, the trabecular thickness and trabecular area of proximal tibia in experiment group decreased(P<0.05), and osteoclast number/space of proximal tibal increased in SCI 6-weeks group(P<0.05). The maximal load of femur shaft reduced in SCI 6-weeks(P<0.05). In SCI 12-weeks group, BV/TV of proximal tibia reduced except for above changes(P<0.05). The maximal load of femur shaft further decreased(P<0.001), the structural rigidity of femur shaft reduced too(P<0.05). Conclusion:The hinder limb bone histomorphometric and biomechanical characterization are deteriorated significantly in rats with SCI at SCI 6-weeks. The damage is more serious at SCI 12-weeks.