Comparison of tissue reaction with chondroitinase ABC and chymopapain in rabbits as the basis of clinical application in chemonucleolysis.

Although chemonucleolysis with chymopapain is an approved treatment for lumbar intervertebral disk herniation, recent serious complications have raised doubt concerning its safety. It is therefore necessary to search for a safer and more selective agent than chymopapain for chemonucleolysis. Experimental chemonucleolysis with chondroitinase ABC was thus tested and compared with chymopapain. Acute tissue reactions to chondroitinase ABC were investigated and compared with chymopapain. The epidural space, yellow ligament, sciatic nerve, knee joint, and Achilles tendon were examined. Chymopapain damaged nervous and ligamentous tissues as well as cartilaginous tissue. Chondroitinase ABC did not damage nervous and ligamentous tissue. Chondroitinase ABC affected only cartilaginous tissue, and its action was chiefly limited to digestion of the matrix. Chondroitinase ABC has high enzymatic specificity for matrix in vivo. In addition, chondroitinase ABC is less toxic to noncartilaginous tissues than chymopapain. Chondroitinase ABC might be a more suitable and safer enzyme than chymopapain for chemonucleolysis.