椎旁肌肉损伤对腰椎椎体骨质量的影响

Effect of lumbar dorsal muscle injuries on lumbar vertebral bone quality of rat

目的探讨肌肉破坏对局部腰椎椎体骨质量的影响。方法将30只20周龄、雌性SD大鼠，随机分为3组：对照组（伪手术组、双侧背部侧正中切口，CNT）、双侧竖脊肌组（切除双侧腰椎旁竖脊肌，RESM）以及去势组（切除双侧卵巢，OVX）。术后第3个月取材腰椎椎体（L4-6）依次进行骨密度、显微CT、椎体压缩实验等检测。结果在术后第3个月RESM组骨密度明显地低于对照组CNT[（0.211±0.028） g/cm^2比（0.253±0.021） g/cm^2，P〈0.01]，然而，OVX和RESM两组之间骨密度差异不明显[（0.197±0.015） g/cm^2比（0.211±0.028） g/cm^2，P〉0.05]。在显微CT三维重建及椎体显微形态计量学分析中，相比于对照组CNT，实验组OVX、RESM的骨小梁都更为稀疏，骨小梁数目和骨小梁之间相互连接较少，特别是OVX骨小梁网络的疏松趋势更为明显。在椎体压缩实验中，实验组OVX和RESM较之CNT组的最大载荷、能量吸收、最大应力以及弹性模量均显著的减低（P〈0.01）。RESM上述4个生物力学参数均显著高于OVX（P〈0.05）。结论椎旁肌肉的完整性和活力对于维持邻近椎体骨质量具有重要意义，切除双侧竖脊肌可致局部椎体骨质量明显减低，椎旁肌肉萎缩或损伤可能会引起椎体骨质疏松。

ObjectiveTo explored the effects of lumbar dorsal muscle damage on local lumbar vertebral bone quality.MethodsThirty SD female rats, at age of 20 weeks, were randomly divided into three groups： control group, or say pseudo surgery group, an incision in the back were performed as CNT; bilateral erector spinal muscle group in which group bilateral lumbar erector spinal muscle were removed as RESM; castration group in which bilateral ovaries were resected as OVX.After three months, bone mineral density, microscopic CT and vertebral compression test were taken in lumbar vertebral （L4-6） in turn.ResultsAfter three months bone mineral density in RESM group was obviously lower than the control group [（0.211±0.028） g/cm^2 vs（0.253±0.021） g/cm^2, P〈0.01], however, there was no significant difference between OVX and RESM[（0.197±0.015） g/cm^2 vs（0.211±0.028） g/cm^2, P〉0.05]. In microscopic CT three-dimensional reconstruction and bone histomorphometry analysis, compared with control group CNT , in the experimental groups OVX and RESM, bone trabecula of vertebral bodies were more sparse, the overall number and interconnection of trabecula were less.Especially in the OVX, osteoporotic trend of trabecular network trend is more obvious.In vertebral compression test, the maximum load, energy absorption, the maximum stress and elastic modulus in both OVX and RESM were significantly reduced （P〈0.01）. In the RESM the above four biomechanical parameters were significantly higher than those of OVX （P〈0.05）.ConclusionIntegrity and vigor of paravertebral muscles would be of great significance to maintain adjacent vertebral bone quality.Resection of lumbar dorsal muscles could lead to a significant decrease of local vertebral bone quality.Damage and atrophy of lumbar dorsal muscle could cause osteoporosis of vertebral bodies.