兔颈椎终板胶原结构变化对运动节段力学性能的影响

The effect of the changes of collagen texture of rabbit's cervical cartilagous endplate on biomechanical properties of the cervical segmental motion

目的 通过测定兔退变颈椎运动节段力学参数的改变,观测其软骨终板胶原的超微结构变化,为退变的椎间盘显现异常力学特性作材料结构上的探讨。方法 将24只家兔随机分为对照组和模型组,模型组家兔保持45°低屈曲位5 h/d,取C5,6、C6,7进行生物力学测定,同时电镜观察终板胶原组织结构改变,总结分析终板材料的结构变化对运动节段力学性能的影响。结果 模型组终板抗扭强度、抗压强度、断裂时的最大形变都低于对照组,胶原排列从有序、致密、规整到紊乱、松散、溶解,并随造模进程的深入而加剧。结论 长时间的应力不均状态,造成椎间盘终板材料力学特性改变;终板胶原结构改变是颈椎间盘生物力学性能减退的原因之一。

Objective To probe the material texture base for abnormal biomechanical properties on the cervical segmental motion by measuring biomechanical parameters and observing the changes of collagen texture, under ultramicroscope Methods 24 rabbits were divided randomly into the model gruop and the control. The model rabbits were kept lower flexion at 45° for 5 h/d, the parts of C5,6、C6,7 were selected to determine the biomechanical properties of motion and observe the collagen texture. The relations between the changes of biomechanical properties of segmental motion and the changes of collagen texture were summarized. Results The significant decrease of anti-twisting, anti-compressive strength and largest deformation in end-plate were showed in the model group;the shape of collagen texture was changed from systematical, compact, regular to disorder, inattentive,dissolved and turning wores along with the developing of model-making. Conclusion The material mechanical changes of cartilaginous endplate can be induced by abnormal stress in a long period of time; the changes of collagen texture might be the one of the pathogeneses of intervertebrar disc degeneration.