兔纤维环损伤椎间盘退变模型观察神经长入的实验研究

In vivo study of innervation of degenerative intervertebral discs in rabbit anular-injury model

目的:用2种不同方法损伤纤维环诱发椎间盘退变,观察椎间盘退变及神经纤维长入退变间盘的病理过程。方法:分别用11号刀片(刀片损伤组)和16号针刺(针刺组)5 mm深度损伤纤维环,致髓核突出椎间盘退变;在不同时间点采用X线、MRI和组织学方法进行椎间盘退变的评价,免疫组化方法PGP 9.5和GAP 43特异性神经抗体染色观察退变椎间盘神经纤维长入的过程。结果:与正常对照组相比,刀片损伤组和针刺组术后2周,受损椎间盘高度和T2信号强度开始逐渐下降(P<0.01),与此同时其组织结构也发生退变,其中刀片损伤组椎间盘退变过程和程度较针刺组快。术后12周纤维环损伤处髓核突出瘢痕组织形成。免疫组化:正常椎间盘仅在纤维环最外层有神经纤维分布且与纤维环相平行;刀片损伤组瘢痕组织表面及深部散在分布神经纤维,深度>1 mm;针刺组仅在瘢痕组织外层及浅部区域有神经纤维分布,且刀片损伤组较针刺组有更广泛的神经长入。结论:5 mm深度11号刀片损伤、16号针刺兔纤维环退变模型在损伤后发生一种进展的逐渐退变过程,而且刀片损伤纤维环退变快,神经纤维分布广而深。这种进展的病理过程可能与源性腰痛密切相关。

Objective： To observe degenerative intervertebral disc and to examine innervation of degenerative discs in the rabbit anular-injury model. Methods： Two different magnitudes of anular injury at 5 mm depth were performed by 11 blade or 16 gauge needle at the L3-L4 or L5- L6 discs in New Zealand white rabbits （n=48,2.5-3.0 kg）. Disc degeneration was evaluated by radiographic,MRI and histological examination at different time points after surgery. To identify nerve ingrowth into disc, two general markers PGP 9. 5 and GAP 43, for nerve fibers were examined by immunohistochemistry. Results： Significant decreases in disc height and signal intensity in magnetic resonance imaging were observed in 11 blade group and 16 G puncture group （P〈0.01）. 16G puncture group induced slower and more progressive disc degeneration companed with the stab group and control group. At the 12-week time point ,nucleus pulposus tissues were extruded and scar tissues formed outside the disc. In stab discs,nerve ingrowth was scattered on the surface of injury site and in the deeper part of the scar tissues,more than 1 mm from the surface. However,in punctured discs,PGP 9.5 and GAP 43-immunoreative fibers were only observed in the outmost part of the scar tissues and superficial area. More nerve fibers were observed in stab group. Conclusion： Innervation may act as a source of discogenic pain which is associated with intervertebral disc degeneration caused by disc anular injury.