TREATMENT OF INTERVERTEBRAL DISC WITH CHONDROITINASE-ABC RESULTS IN REVERSIBLE DEGENERATION IN RAT TAIL MODEL

摘要

Injury models of intervertebral disc provide a strong tool for studying the etiology of degenerative disc disease. Enzymatic degradation of the IVD with injection of chondroitinase ABC (ChABC) has been used in models of disc injury in rats, rabbits and goats [1-3], as well as used to induce repair of herniated discs in rabbits via chemonucleolysis [4, 7]. In a recent study, we investigated the dose effect of ChABC dosage on inducing disc degeneration [5]. Consistent with previous studies, our results found that a low dosage of ChABC (0.1 U/ml) resulted in decreased mechanical properties and glycosaminoglycan (GAG) content by 4 weeks post injections. Interestingly, when the dosage was increased to 10 U/ml, results indicated no measurable difference in GAG content or compressive mechanical properties after 4 weeks compared to sham saline injection or intact controls. These findings suggested that rat IVD was either unaffected by the enzymatic injection, or that it was capable of mounting a repair process after degradation with ChABC. In this study, we examined the temporal response of rat caudal IVD to injection with ChABC at the high dose of 10 U/ml. Animals were examined at 1 week and 4 weeks post injection. We hypothesize that the injection of ChABC at a high dosage (10 U/ml) will result in significant GAG loss and mechanical weakening at 1 week post injection, and such degradation will be fully recovered by 4 weeks post injection.