三种方法建立兔椎间盘退变模型的比较研究

A COMPARATIVE STUDY ON ESTABLISHING RABBIT INTERVERTEBRAL DISC DEGENERATION MODELS BY THREE METHODS

目的选择可靠的椎间盘退变动物模型,能为研究椎间盘退变性疾病的发病机制和治疗提供重要的实验载体。通过3种不同损伤方式诱导建立兔椎间盘退变模型,并采用生物化学和影像学方法比较其退变过程及特点。方法取健康6月龄新西兰大白兔25只,体重2.0～2.5kg,随机分为5组,每组5只,每只均选取L3、4、L4、5、L5、6共3个节段椎间盘进行实验。其中A、B组为纤维环穿刺组,分别采用18G和22G针头穿刺;C组为髓核抽吸组;D组为终板破坏组;E组为假手术对照组。分别于术后2、4、8、16和32周每组各取1只动物行CR和MRI检查,测量椎间盘相对高度,评估并记录各椎间盘退变分级的分值;然后处死实验动物获取椎间盘髓核组织,测定其中的水含量和硫酸化糖胺多糖(sulfated-glycosaminoglycan,s-GAG)含量。结果影像学检查显示除E组外,A～D组手术节段的椎间隙随时间延长逐渐狭窄,上下软骨终板出现不同程度钙化,椎体前缘骨赘形成,椎间盘髓核信号强度呈现逐渐降低趋势。与E组相比,A～D组椎间隙相对高度和椎间盘分级分值分别在4周内不同时间点开始差异有统计学意义(P<0.05);C、D组出现明显变化时间早于A、B组。A～D组髓核组织的水含量和s-GAG含量随时间延长也呈逐渐下降的变化趋势;与E组相比,A～D组两者含量分别在8周内不同时间点开始差异有统计学意义(P<0.05);C、D组出现明显下降趋势的时间早于A、B组。结论3种手术损伤方式均成功建立了兔椎间盘退变模型。终板破坏法和髓核抽吸法较纤维环穿刺法所诱发的退变过程出现更早,进展较快且退变程度更重。

Objective The reliable animal model of intervertebral disc degeneration,can provide important experimental carrier to research pathogenesis and treatment of intervertebral disc degeneration.To establish three kinds of injury induced rabbit intervertebral disc degeneration models and to compare the characteristics among them by using biochemical and radiological methods.Methods Twenty-five healthy New Zealand white rabbits（weighing 2.0-2.5 kg）were randomly divided into 5 groups（n=5）.The L3,4,L4,5 and L5,6 discs in each rabbit were used for study.Groups A and B were for annulus puncture with an 18-gauge needle and a 22-gauge needle,respectively;group C was for nucleus aspiration;group D was for endplate injury and group E was used as a control.The lumbar spinal plain radiographs and magnetic resonance images（MRI） were evaluated,the raltive height of intervertebral disc was measured and the grades of disc degeneration were recorded 2,4,8, 16,and 32 weeks after operation.The water and the sulfated-glycosaminoglycan（s-GAG）contents of the nucleus were measured after sacrifice（randomly choose one rabbit from each group at each time point）.Results In groups A,B,C and D,the height of intervertebral space in plain radiograph gradually decreased after operation.The anterior bony excrescences of vertebral body and varying degrees of calcification of endplate were also observed.The signal intensity of disc in T2-weighted magnetic resonance imaging decreased with time too.Compared with group E,the significant changes of height of intervertebral discs and grades of disc degeneration in MRI occurred at different time points within 4 weeks in groups A-D（P0.05）.The significant change in groups C and D occured earlier than in groups A and B.The water and s-GAG contents of discs decreased gradually in groups A-D after operation,while the significant change occurred at varying time points within 8 weeks compared with group E （P0.05）.The apparent downward trend in groups C and D occured earlier than in groups A and B.Conclusion All three methods are successful in inducing intervertebral disc degeneration.The degenerative process induced by endplate injury and nucleus aspiration is faster and more severe than that induced by annulus puncture.