title: Serial changes in the rate of proteoglycan synthesis after chemonucleolysis of rabbit intervertebral discs.
abstract: METHODS
  Serial changes in the rate of proteoglycan synthesis in rabbit discs after chemonucleolytic treatment with chymopapain and chondroitinase ABC were measured using an in vitro method.
  
  
  OBJECTIVE
  To determine the retained ability of the intervertebral disc to synthesize proteoglycans after chemonucleolytic treatment.
  
  
  BACKGROUND
  Most previous studies describe radiologic and histologic changes that occur after chemonucleolytic treatment. However, in humans it is not clear whether reconstitution of the disc space with normal nucleus proteoglycans can occur with time.
  
  
  METHODS
  Twenty-five rabbits were treated with chymopapain (10 units/0.1 mL/disc) and chondroitinase ABC (5 units/0.1 mL/disc) by intradisc injection. Five rabbits were killed at each interval, 1, 2, 4, 8 and 12 weeks after injection. Radiologic changes in the disc height were noted, and the rate of proteoglycan synthesis was determined biochemically.
  
  
  RESULTS
  After injection, no significant recovery of disc height was seen in either enzyme group after the initial disc narrowing. The average rate of proteoglycan synthesis in control rabbit intervertebral discs, those which had not been surgically treated, was 27.1 (x 10(-6) mmols sulphate/hour/dry weight). Twelve weeks after injection, the values were 21.6 in the saline group, 8.9 in the chondroitinase ABC group, and 8.2 in the chymopapain group.
  
  
  CONCLUSIONS
  Doses within the therapeutic range can damage disc cells, at least in the rabbit, so that proteoglycan synthesis declined to 30% of control rates, and no significant recovery of disc height was observed.
authors.affiliation: Department of Orthopaedic Surgery, School of Medicine, Nagoya University, Japan. sumida@ortho.med.nagoya-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Sumida
authors.forename: K
authors.initials: K
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Aoki
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuyama
authors.forename: H
authors.initials: H
authors.lastname: Iwata
mesh_terms: D000818:Animals; D019765:Chondroitin ABC Lyase / Q000627:therapeutic use*; D002917:Chymopapain / Q000627:therapeutic use*; D007278:Injections, Spinal; D007403:Intervertebral Disc / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism*; D007404:Intervertebral Disc Chemolysis; D008297:Male; D011509:Proteoglycans / Q000096:biosynthesis*; D011817:Rabbits; D011859:Radiography
chemical_list: D011509:Proteoglycans; D002917:Chymopapain; D019765:Chondroitin ABC Lyase