Proteoglycans in the nucleus pulposus after chondroitinase ABC treatment

Abstract Recently, chondroitinase ABC has attracted attention as a possible replacement enzyme for chymopapain. In this study, experimental chemonucleolysis of the canine intervertebral disc with chondroitinase ABC and chymopapain was studied during a 52-week period using roentgenograms, MRI, and biochemical techniques. Lateral roentgenograms and MRI (T2-weighted images) were used to examine changes in disc space and water content, respectively. High-performance liquid chromatography was performed to measure changes in quantity, molecular weight, and acidity of proteoglycans and chain length of glycosaminoglycans. Disc space narrowing and reduction in disc water content after chondroitinase ABC treatment were less than after chymopapain. Similarly to chymopapain, chondroitinase ABC degraded proteoglycans in the nucleus pulposus, and decreased their quantity. However, large differences in the quantity, molecular weight, and acidity of the re-synthesized proteoglycans, and in the chain length of the re-synthesized glycosaminoglycans, were observed between the two enzymes. This suggests that the proteoglycans and glycosaminoglycans re-synthesized after degradation of the original nucleus pulposus proteoglycans by chondroitinase ABC differ from those of proteoglycan core proteins produced by chymopapain. The difference in disc space narrowing and the changes in disc water content between the two enzymes might result from differences in the characteristics of the re-synthesized proteoglycans.