Investigation of the short-term effect of chemonucleolysis with chondroitinase ABC

Chondroitinase ABC (C-ABC) is expected to be a novel agent for chemonucleol ysis. The effect of C-ABC was investigated by magnetic resonance (MR) and r adiograph. C-ABC was administered into the lumbar intervertebral disks on t he clinically normal beagles (n=5), in a dose of 50 mul (12.5 units as C-AB C). MR scans were performed pre-dose, and 1, 3, 7, 14 and 28 days after adm inistration of C-ABC, and the signal intensity (SI) of the nucleus pulposus was measured. Radiographs were taken pre-dose, and 1, 2, 3, 4, 5, 6, 7, 14 and 28 days post-dose, to evaluate narrowing of the disk space in terms of height index (HI). In addition, the quantity of the chondroitin sulfate (C S) and the hyaluronic acid (HA) in the nucleus pulposus were measured by hi gh performance liquid chromatography on day 28 after dosing. SI and HI cont inuously decreased, following the injection to 37.1% and 78.9% of the pre-d ose values, respectively. Statistically significant differences (p <0.01) w ere observed between the C-ABC group and the control group in the respects on day 1 post-dose. CS and HA contents of the nucleus pulposus were noted t o be significantly decreased on day 28 (p <0.01) in the treated,group. This agent proved to degenerate proteoglycans in the nucleus pulposus, thus pro gressively reducing the interdiskal pressure from day 1 post-dose onwards. It is concluded that C-ABC is expected to afford its efficacy from early in the course of chemonucleolysis.