目的:通过在同一新西兰兔体内建立两种腰椎间盘退变程度不同的模型,为今后运用磁共振T2 mapping成像定量动态观察椎间盘退变过程提供实验基础。方法每只新西兰兔(n=6)均选L4/5及L7/S1椎间盘为空白对照组,L5/6椎间盘为终板下椎骨缺血组,L6/7椎间盘为纤维环穿刺组。在X线透视导引下经皮穿刺新西兰兔(n=6)L6/7椎间盘纤维环,同时经皮穿刺兔L5/6椎间盘两侧终板下椎骨并注射平阳霉素。造模前、造模后第4、7、10及13周使用1.5 T 磁共振成像仪进行新西兰兔腰椎矢状位T2 WI扫描检查。用生物化学方法检测椎间盘组织蛋白多糖含量。结果纤维环穿刺组的腰椎间盘T2 WI信号在造模后第4周开始降低,而终板下椎骨缺血组的腰椎间盘T2 WI信号在造模后第13周才发生下降。造模术后第13周新西兰兔两个空白对照组(L4/5、L7/S1)椎间盘之间的腹、背侧纤维环及髓核组织的蛋白多糖含量无统计学差异(P>0.05)。造模术后第13周终板下骨缺血组的椎间盘腹、背侧纤维环及髓核组织的蛋白多糖低于两个空白对照组(L4/5和L7/S1)(P<0.01),明显高于纤维环穿刺组(P<0.01)。结论采用微创方法可在新西兰兔体内同时构建纤维环穿刺或终板下椎骨缺血诱导的腰椎间盘退变模型。与纤维环穿刺模型相比,终板下椎骨缺血模型的椎间盘呈缓慢的退变过程。
Objective To establish a model of intervertebral disc degeneration(IDD)in rabbit for T2 mapping research. Methods The annulus fibrosus at L6/7 was punctured under fluoroscopic guidance in 6 New Zealand rabbits.Pingyangmycin was also injected into the vertebral bodies adjacent to the vertebral endplates at L5/6.Sagittal T2-weighted MRI was acquired before,4,7,10 and 13 weeks after the procedure.The proteoglycans concentrations in the discs were measured by biochemical methods.Results The T2 signal intensities of the L6/7 intervertebral discs began to decrease at 4 weeks after annulus fibrosis puncture compared to that of L5/6 at 13 weeks after subendplate vertebral injection.The proteoglycans concentrations of the normal L4/5 and L7/S1 discs were not significantly different(P>0.05)whereas the proteoglycans concentrations of L5/6 were significantly lower(P<0.01)than that of L4/5 and L7/S1 and significantly higher than that of L6/7(P<0.01)at 13 weeks.Conclusion IDD models can be successfully established by puncturing the annulus fibrosus or by the slower process of inducing subendplate vertebral ischemia in the same rabbit.