终板蛋白多糖的变化对颈椎间盘力学性能的影响(英文)

Effect of proteoglycan changes in cartilage endplate on biomechanical behavior of cervical intervertebral disc

背景:蛋白多糖是软骨终板的主要组成部分,是维持椎间盘力学性能的生化基础。目的:通过测定退行性变颈椎间盘压缩性能及观测软骨终板基质蛋白多糖的变化,为退行性变的椎间盘显现异常力学特性作一分子机制上的探讨。设计:随机对照实验研究。地点和对象:实验在浙江中医学院生物力学室完成。对象为清洁级日本大耳白家兔24只,由浙江中医学院实验动物中心提供。干预: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5h/(次·d)。于造模后1,2,3月测量力学观察指标和糖胺多糖,分析颈椎间盘退变时基质各成分的系统变化及其对椎间盘力学性能的影响。主要观测指标:椎间盘生物力学性能,椎间盘终板糖胺多糖总量,硫酸软骨素和硫酸角质素比值和透明质酸含量。结果:模型组终板抗压强度、断裂时的最大形变、终板基质蛋白多糖总含量、硫酸软骨素/硫酸角质素比值、透明质酸含量都低于对照组(t=1.78～6.23,P<0.05),并随造模进程的深入而减小。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;颈椎间盘基质蛋白多糖含量和成分改变是颈椎间盘生物力学性能减退的主要原因之一。

BACKGROUND:Proteoglycan is the main component of cartilage endplate,which is the biochemical basis in maintaining the biomechanical behavior of cervical intervertebral disc. OBJECTIVE:To discuss the molecular mechanism for abnormal biomechanics behavior in the cervical intervertebral disc with retrogressive changes by assaying the compressive capability of cervical intervertebral disc with retrogressive changes and observing the changes of proteoglycan in cartilage endplate. DESIGN:A randomized controlled study was conducted. SETTING and PARTICIPANTS:The study was completed in the Department of Biomechanics,Zhejiang College of Traditional Chinese Medicine.The subjects were 24 Japanese clean white rabbits obtained from Center for Experimental Animals,Zhejiang College of Traditional Chinese Medicine. INTERVENTIONS:Twenty four Japanese white rabbits were randomly divided into control and model group.The model rabbits were kept at 45°flexion for 5 hours once daily.At 1,2,and 3 months after model establishment,the mechanics index and GAG content were measured to analyze the systemic changes of stromal components of cervical intervertebral disc with retrogressive changes and the effect on the biomechanics capacities of cervical intervertebral disc. MAIN OUTCOME MEASURES:C5-6 disc was chosen to determine the biomechanical characters,the GAG content,ratio of chondroitin sulphate(CS) to keratin sulphate(KS) and hyaluronic acid(HA) content. RESULTS:There were significant decreases of antipress intension and largest shape change,GAG content,CS/KS ratio,and HA content in model group compared with that of control group(t=1.78-6.23,P< 0.05),which decreased over time. CONCLUSION:The specific mechanic changes of intervertebral disc can be induced by long time abnormal stress.The changes of proteoglycan content may be the major reason of intervertebral disc degeneration.