实验性无创兔颈椎间盘退变模型的建立

Establishment of rabbits experimental model for cervical intervertebral disc degeneration

目的 :观察长时间异常应力环境下兔颈椎间盘的组织形态、基质生化成分和生物力学性能变化 ,为防治颈椎病的研究提供动物模型和实验依据。方法 :选取 35只家兔 ,随机分为对照组 (2 0只 )、模型组 (15只 ) ,造模家兔颈椎处于低头屈曲 4 5°位异常应力环境下 5h/d。动物处死后 :①颈椎间盘光镜和电镜下观察组织形态学变化 ;②免疫组化和生化方法测定基质胶原和蛋白聚糖 (proteoglycan ,PG)含量和成分的变化 ;③功能节段生物力学性能测试。比较各组间可能存在的差异。结果 :①对照组颈椎间盘组织形态、基质胶原和PG含量和成分及生物力学性能无明显变化 ;②模型组颈椎间盘发生软骨细胞变性、坏死 ,髓核皱缩 ,纤维环胶原纤维变性、排列紊乱 ,软骨终板钙化、断裂 ,胶原纤维排列紊乱等组织形态学改变。髓核和软骨终板中PG总量、硫酸软骨素 (chondroitinsulphate,CS)含量和Ⅱ型胶原表达下降 ,纤维环中Ⅰ型胶原表达增加 ,椎间盘压缩、扭转生物力学性能下降 ,并随着异常应力作用时间的延长而表现更为显著。结论 :长时间处于异常应力环境下能使兔颈椎间盘组织形态、基质生化成分及生物力学性能均发生明显退行性改变 。

Objective:To establish a new cervical intervertebral disc degeneration animal model by characterizing the changes of cervical intervretebral disc histopathology,biochemistry and biomechanics associated with disc degeneration through keeping the rabbits cervical spine into forty-five-degree flexion for five hours once a day.Methods:Thirty-five Japanese white rabbits were randomly divided into control and model groups.Rabbits of the model group were kept at forty-five-degree flexion for five hours once a day.After sacrificed:① Observing the histopathological changes under light microscopy and transmission electronic microscopy;② Determining collagen type Ⅰ,Ⅱ and proteoglycan(PG)components content;③ The regular biomechanical test made on the function of spinal unit.Results:① Rabbits in the control group showed no histopathological,biochemical and biomechanical changes on cervical intervertebral disc;② In the model group,the pathological changes of the intervertebral disc including:Spit of the annulus fibrosis,dehydration of pulposus nucleus,derangement of the collagen of the annulus fibrosis,calcification,ossification and separation of the cartilage endplate;PG content in the pulposus nucleus and the cartilage endplate decreased significantly,while collagen type Ⅰ expression increased.Biomechanical test showed an significant decrease of resist-compression character of the intervertebral disc.The longer the flexion time,the more significant the results were.Conclusion:A new in vivo animal model was established by keeping the cervical spine into the abnormal stress condition.