两种方法建立兔腰椎间盘退变模型

Establishment of a rabbit model of intervertebral disc degeneration using two methods

背景:国内外学者对椎间盘退变动物模型的建立做了大量工作,通过改变椎间盘力学特性、纤维环损伤、酶化学法等多种建模方式模拟椎间盘退变的病理表现。目的:通过髓核抽吸法和纤维环薄层切除法建立椎间盘退变模型,比较两种方法的造模效果。方法:取6月龄新西兰大白兔20只,通过手术暴露L3-4、L4-5及L5-6椎间盘,随机使用髓核抽吸法和纤维环薄层切除法对L3-4、L4-5椎间盘进行干预:(1)髓核抽吸组——利用16 G针头在椎间盘纤维环穿刺并负压抽吸10 s;(2)纤维环薄层切除组——在显微镜下辅助下,在兔椎间盘纤维环上切除1 mm×2 mm范围的约1/2层纤维环组织(避免切透全层)。于造模第1,3,5,9,13周进行核磁共振、X射线检查及椎间盘Masson染色病理学观察。结果与结论:(1)X射线检查:纤维环薄层切除组椎间隙高度自术后第1周起便发生不同程度降低;髓核抽吸组椎间隙在术后1周及3周轻微降低,自第5周起发生较明显降低;纤维环薄层切除组术后第3,5,9周椎间隙高度指数百分比高于髓核抽吸组(P<0.05);(2)核磁共振检查:两种方法均诱导相应椎间盘发生退变,各组随时间推移椎间盘退变程度逐渐加重,并于9周后均达到4级退变;髓核抽吸组术后1,3,5周的椎间盘退变程度重于纤维环薄层切除组(P<0.05);(3)病理学观察:随时间推移,两组椎间盘髓核及纤维环退变程度逐渐加重;(4)结果表明:髓核抽吸法和纤维环薄层切除法均能诱导椎间盘退变,纤维环薄层切除法在5周内造成的椎间盘退变程度较髓核抽吸法轻,纤维环薄层切除法在纤维环上所造成的标示部位可作为纤维环修补研究的靶点。

BACKGROUND： Scholars around the world have attributed to establish the animal models of intervertebral disc degeneration（IVD） to imitate the IVD pathological manifestations by changing mechanical properties of the intervertebral disc, annulus fibrosus injury, and enzymatic method. OBJECTIVE： To establish the IVD model by nucleus aspiration and partial annulus incision, and to compare the modeling effects of the two methods.METHODS： Twenty 6-month-old New Zealand white rabbits were selected, in which the IVD models were then induced by nucleus aspiration（group A） or partial annulus resection（group B） of surgically exposed L3-4, L4-5： group A, subjected to annulus puncture with a 16-gauge needle and 10-second negative pressure sunction; group B, about 1/2 part of the annulus（1 mm×2 mm） was cut under microscope, careful not to make a full-thickness incision. MRI, X-ray examinations and Masson staining were performed at 1, 3, 5, 9, and 13 weeks after modeling. RESULTS AND CONCLUSION： X-ray examination： in the group B, the intervetebral space height began to decline in varying degrees at the 1st week postoperatively; in the group A, the intervetebral space height was decreased slightly at postoperative 1 and 3 weeks, and this reduction became obvious since the 5th week. The percentage of intervetebral space height in the group B was significantly higher than that in the group A at 3, 5 and 9 weeks postoperatively（P〈0.05）. MRI examination： the IVD could be induced by these two methods, and became severer with time, which was classified as grade 4 according to the modified Thompson grading criteria at the 9th week. The IVD degree in the group A was significantly severer than that in the group B at postoperative 1, 3 and 5 weeks（P〈0.05）. Masson staining showed that the IVD degree became severe with time in both two groups（P〈0.05）. Both two methods can induce the IVD. Besides, the IVD degree caused by the partial annulus incision is slighter than that of the nucleus aspiration within 5 weeks, and the incision site is a potential target of annulus repair.