Experimental chemonucleolysis with chondroitinase ABC.

Chemonucleolysis has recently become an established treatment for intervertebral disc protrusion. However, the exact mechanism of chemonucleolysis is still unknown. If mechanisms of chemonucleolysis include diminution of intradiscal pressure followed by subsequent regeneration of the nucleus pulposus, then a more selective enzyme for glycosaminoglycan, chondroitinase ABC, might be used for chemonucleolysis instead of chymopapain. Thus experimental chemonucleolysis with chondroitinase ABC compared with chymopapain was investigated. In rabbits, chondroitinase ABC is as effective for chemonucleolysis as chymopapain, but the chemonucleolysis process with chondroitinase ABC was milder than with chymopapain. At an early chemonucleolysis phase, chondroitinase ABC action was chiefly limited to digestion of the matrix, and a large number of cells in the nucleus pulposus remained. During long-term observations of chemonucleolysis with chondroitinase ABC, nuclear structure was restored to a nearly normal state. Although limited, this study indicates that chondroitinase ABC might be more suitable than chymopapain for chemonucleolysis.