EXPERIMENTAL CHEMONUCLEOLYSIS WITH CHONDROITINASE ABC IN MONKEYS

Study Design. Experimental chemonucleolysis with chondroitinase ABC as compared with chymopapain was investigated in monkeys. The effects of these two enzymes were analyzed morphologically and biochemically. Ob jectives. The results of the present study facilitate the clinical app lication of chondroitinase ABC. Summary of Background Data. Many exper imental studies on chemonucleolysis with chondroitinase ABC have been reported mostly in rabbits. Further examination in animals that are mo re similar to humans is necessary for its clinical application. Method s. Ten mature rhesus monkeys were used. Lumbar intervertebral discs fr om six monkeys were injected with either chondroitinase ABC, chymopapa in, or physiologic saline. The animals were killed not more than 6 wee ks after injection, and their discs were examined morphologically and biochemically. The remaining four monkeys were used for a longer follo w-up study to determine the changes in chondroitinase ABC-injected dis cs. Results. Degenerative changes of discs were more severe with the i njection of chymopapain, although the content of hyaluronic acid, chon droitin sulfate, and dermatan sulfate decreased more with the injectio n of chondroitinase ABC. In a longer follow-up study, chondroitinase A BC-injected discs recovered somewhat morphologically and biochemically . Conclusions. The results confirm that selective degradation is achie ved with chondroitinase ABC in vivo in monkeys and that chondroitinase ABC is less toxic to discs than chymopapain is. From these considerat ions, chondroitinase AB is believed to have a high potential for clini cal application.