建立剪切应力导致椎间盘退变模型

目的 建立剪切应力导致椎间盘退变的在体动物模型，探索剪切应力与椎间盘退变之间的关系。方法 20只成年日本大耳白兔随机平均分成2组。加载组通过手术在动物L4/5节段植入自行研制的剪切应力加载装置，并加载50 N的剪切力4周；对照组只植入加载装置但不加载剪切力。4周后处死所有动物并对所有相关节段的椎间盘做病理检查。结果 术后的影像学检查显示加载装置位于动物腰椎，手术过程和植入的加载装置对实验动物的日常活动与饮食均无影响。病理学检查发现加载组椎间盘的纤维环组织排列紊乱，正常髓核细胞明显减少。结论 新型装置的设计减少了对动物椎体的创伤，并且可以提供可靠的剪切应力；在体动物模型的建立揭示一定的剪切应力可导致动物椎间盘退变，对进一步研究载荷与椎间盘退变间的关系具有较大的意义。

Development of shear force-induced intervertebral disc degeneration model

Objective To develop a shear force-induced intervertebral disc degeneration (IDD) in vivo animal model, and investigate the relationship between shear stress and IDD. Methods A total of 20 Japanese white rabbits were randomly divided into two groups. In loading group (n=10), shear force of 50 N was applied on the disc of L4/5 for 4 weeks by a custom-made external shear force loading device. In control group (n=10), the animals underwent a sham operation with the external loading device situated, but their discs remained unloaded. After 4 weeks, all the intervertebral discs of L4/5 were executed for the pathologic examination. Results The postoperative radiographic examination showed a perfect position of the loading device, and the operation process and implanted loading device had no effect on daily activities and diet of the experiment animals. The pathological examination showed an irregular arrangement of annulus fibrosus and a significant decrease of normal nucleus pulposus cells in loading group. Conclusions The new custom made device greatly reduced the wounds on animal vertebra and provided a reliable shear force. The development of in vivo animal model indicates that IDD can be induced by shear force, which is of significance to further study the relationship between loading and IDD.