title: Serum keratan sulfate transiently increases in the early stage of osteoarthritis during strenuous running of rats: protective effect of intraarticular hyaluronan injection.
abstract: BACKGROUND
  Osteoarthritis is influenced by genetic and environment factors, including mechanical stress; however, the relationship between running and the development of osteoarthritis remains a matter of controversy. We investigated whether osteoarthritic change could be obtained in a rat strenuous running model, whether serum keratan sulfate in rats could be detected by HPLC and was associated with onset or progression of osteoarthritis, and whether hyaluronan injection suppressed development of osteoarthritis and elevation of serum keratan sulfate.
  
  
  METHODS
  Wistar rats were forced to run 30 km in 6 weeks on a treadmill machine. Articular cartilage of the knees was evaluated macroscopically and immunohistologically. Serum keratan sulfate was examined every week by HPLC. The effect of weekly knee injection of hyaluronan was also investigated.
  
  
  RESULTS
  Cartilage surfaces stained with India ink became irregular, metachromasia by safranin-O staining appeared to be almost lost, and Mankin's score significantly worsened after 30 km of running. Serum keratan sulfate in rats was detected by HPLC and transiently increased (peaked at 3 to 4 weeks) along with depletion of keratan sulfate in cartilage tissue. Hyaluronan treatment suppressed morphological progression of osteoarthritis and elevation of serum keratan sulfate.
  
  
  CONCLUSIONS
  Rat strenuous running induced osteoarthritis. Serum keratan sulfate was associated with progression of osteoarthritis. Weekly intraarticular injection of hyaluronan controlled the development of osteoarthritis, and the effect was reflected by serum keratan sulfate.
authors.affiliation: Section of Orthopedic Surgery, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan. tang.orj@tmd.ac.jp
authors.forename: Tao
authors.initials: T
authors.lastname: Tang
authors.forename: Takeshi
authors.initials: T
authors.lastname: Muneta
authors.forename: Young-Jin
authors.initials: YJ
authors.lastname: Ju
authors.forename: Akimoto
authors.initials: A
authors.lastname: Nimura
authors.forename: Kyosuke
authors.initials: K
authors.lastname: Miyazaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Masuda
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Mochizuki
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sekiya
mesh_terms: D000818:Animals; D002358:Cartilage, Articular / Q000378:metabolism / Q000473:pathology; D002851:Chromatography, High Pressure Liquid; D018450:Disease Progression; D006614:Hindlimb; D006820:Hyaluronic Acid / Q000008:administration & dosage* / Q000494:pharmacology; D007150:Immunohistochemistry; D007270:Injections, Intra-Articular; D007632:Keratan Sulfate / Q000097:blood* / Q000378:metabolism; D009043:Motor Activity; D009994:Osmolar Concentration; D010003:Osteoarthritis / Q000097:blood / Q000473:pathology* / Q000503:physiopathology*; D010807:Physical Endurance; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D006820:Hyaluronic Acid; D007632:Keratan Sulfate