Comparisons between needle puncture and chondroitinase ABC to induce intervertebral disc degeneration in rabbits.

PURPOSE: This study aimed to compare the effect of needle puncture and chondroitinase ABC (ChABC) injection on inducing intervertebral disc (IVD) degeneration (IVDD) in rabbits. METHODS: Sixteen New Zealand white rabbits were used in this study. Briefly, the rabbits were divided into four groups. In the annulus fibrosis (AF) needle puncture group, a 16-G needle was used to puncture the L5-6 and L6-7 IVDs, while in the sham group, these IVDs were not punctured. In the ChABC group, 30 µL 0.5 Unit/mL ChABC was injected into L5-6 and L6-7 IVDs using a 26-G needle, while in the vehicle group, these IVDs were injected with 30 µL phosphate-buffered saline (PBS). X-ray and MRI scans were performed at the 4th, 12th and 16th weeks postoperatively. Histological, immunohistochemical and biochemical analyses were performed at the 16th week postoperatively. RESULTS: Both needle puncture and ChABC successfully established IVDD in rabbits at 4th, 12th and 16th weeks, confirmed by X-ray and MRI scan. The progression of IVDD went in a time-dependent manner. The IVDD in the ChABC group was less severe than in the needle puncture group throughout the study. Aggrecan and type II collagen significantly decreased, while tumor necrosis factor-α and superoxide dismutase 2 increased in the needle puncture and ChABC groups, compared with the sham and PBS groups. CONCLUSIONS: Both AF needle puncture and ChABC injection can successfully induce IVDD in rabbits. Compared with ChABC injection, AF needle puncture can induce more severe IVDD.

Restoration of disc height loss by recombinant human osteogenic protein-1 injection into intervertebral discs undergoing degeneration induced by an intradiscal injection of chondroitinase ABC.

STUDY DESIGN: In vivo study of the effect of an injection of recombinant human osteogenic protein-1 into degenerated discs induced by chondroitinase ABC. OBJECTIVE: To investigate the efficacy of an injection of recombinant human osteogenic protein-1 to induce the recovery of disc height, and biochemical and histologic repair, in discs degenerated through enzymatic digestion by chondroitinase ABC. SUMMARY OF THE BACKGROUND DATA: Chondroitinase ABC is currently proposed as a chemonucleolysis agent; however, postchemonucleolysis degeneration is currently unavoidable. Recombinant human OP-1 has been shown to promote extracellular matrix repair in vitro and in vivo. METHODS: Fifty-four adolescent New Zealand white rabbits were used. Four weeks after an initial injection of chondroitinase ABC (10 mU/disc), 5% lactose (10 microL/disc) or recombinant human osteogenic protein-1 (100 microg in 10 microL lactose/disc) was injected. Disc heights were monitored radiographically at 2-week intervals, and rabbits were killed at 6, 8, 12, and 16 weeks after the initial chondroitinase ABC injections. The intervertebral discs were subjected to histologic and biochemical analyses. RESULTS: Significant disc space narrowing was observed in both groups 2 weeks after the injection of chondroitinase ABC. In the chondroitinase ABC/lactose group, this narrowing progressed after the vehicle injection and was sustained for up to 16 weeks. In the chondroitinase ABC/recombinant human osteogenic protein-1 group, the disc height index showed a significant increase at 6 weeks (lactose vs. recombinant human osteogenic protein-1; P < 0.01); this recovery was sustained for up to 16 weeks. The proteoglycan content was higher in the chondroitinase ABC/recombinant human osteogenic protein-1 group than in the chondroitinase ABC/lactose group. However, histologic changes, after the recombinant human osteogenic protein-1 injection, were not observed. CONCLUSIONS: A single injection of recombinant human osteogenic protein-1 into a rabbit disc dramatically reversed the decrease in disc height induced by chondroitinase ABC chemonucleolysis. The recovery was significant and sustained over the next 12 weeks. The therapeutic effects of both chondroitinase ABC chemonucleolysis and recombinant human osteogenic protein-1 injections should be further explored in higher animals before it is applied to humans.

[Posterior vitreous detachment induced by intravitreal injection of the combination of chondroitinase ABC and matrix metalloproteinase-3].

OBJECTIVE: To investigate the occurrence of enzymatic induction of posterior vitreous detachment (PVD) by the combination of Chondroitinase ABC (CA) and matrix metalloproteinase-3 (MMP-3), so as to seek a noninvasive and effective pharmacologic approach to facilitate and eventually replace the present mechanical vitreous surgery. METHODS: Twenty-four pigmented rabbits were randomly assigned to two groups of twelve each, the experimental group was treated with CA (0.2 U) and MMP-3 (10 ng) combination, the control group was received equivalent dose of balanced salt solution (BSS). Clinical examinations and electroretinography were performed before and after injection. Over a different period of time, the rabbits were euthanized and killed and their eyes were examined histologically. RESULTS: The foci of partial synchisis and clinically named PVD were recognized for the first time three days after injection. Complete liquefaction was found in every eye of experimental group, and in which, 5/8 eyes developed clinically detected PVD one week after injection Histologic section showed PVD with various extent in 3/7, 7/7, 7/7 eyes of experimental group 30 minutes, 60 minutes and one week after injection respectively, and complete PVD in 0/7, 1/7, 5/7 eyes of experimental group at the same periodic intervals as above. By contrast, no vitreous liquefaction was found and only one eye showed confined partial PVD in the control group. Clinic, electrophysiologic and histologic evaluation in all rabbits revealed no evidence of ocular toxicity. CONCLUSIONS: Vitreous 1iquefaction and PVD can be produced shortly after intravitreal injection using a combination of CA and MMP-3, and the two enzymes were cooperative. Synchisis and weakening of vitreoretinal adherence were almost simultaneously. The dose of 0.2 U CA and 10 ng MMP-3 combination proved to be safe and ideal selection to induce PVD.