Establishment of a rabbit model of intervertebral disc degeneration using two methods / 中国组织工程研究

ABSTRACT

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 surgical y 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 ful-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.