title: Quantitative MR T2 measurement of articular cartilage to assess the treatment effect of intra-articular hyaluronic acid injection on experimental osteoarthritis induced by ACLX.
abstract: OBJECTIVE
  The purpose of this study was to investigate whether the effect of treatment with hyaluronic acid (HA) on cartilage in osteoarthritis (OA) can be determined by measuring the magnetic resonance (MR) T2 value of cartilage in an anterior cruciate ligament transection (ACLX) animal model.
  
  
  METHODS
  Eighteen male Sprague Dawley rats were separated randomly into three groups (n=6 for each group). Group 1 was given ACLX and intra-articular (IA) normal saline (NS) injection (ACLX+NS), group 2 was given ACLX and IA HA injection (ACLX+HA), and group 3 was the sham control. The ACLX+NS and ACLX+HA groups received ACLX on the right knee at 8 weeks of age and were then treated with IA NS or HA injection once a week, respectively, for 4 weeks starting at 13 weeks of age. In the sham-control group, the right knee joint was opened surgically but ACLX was not performed at 8 weeks of age. MR T2 measurements were obtained on all rats at 8, 12, and 21 weeks of age, and histological Mankin scoring was performed at 21 weeks of age.
  
  
  RESULTS
  Five weeks after the 4-week treatment, the MR T2 value of the ACLX right knee cartilage was significantly lower in ACLX+HA (29.58+/-1.12ms) than in ACLX+NS (32.04+/-1.39ms) (P<0.05). Five weeks after the 4-week treatment, the Mankin score of the ACLX right knee was significantly lower in ACLX+HA (3.3+/-0.81) than in ACLX+NS (7.3+/-1.03) (P<0.001). The T2 value was significantly and positively correlated with the Mankin score in the ACLX+NS (rho=0.77, P<0.05) and ACLX+HA (rho=0.69, P<0.05) groups.
  
  
  CONCLUSIONS
  This study demonstrates the feasibility of quantitative MR T2 measurement in the early assessment of HA treatment efficiency in a cartilage degeneration model.
authors.affiliation: Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan. gsh5@seed.net.tw
authors.forename: G-S
authors.initials: GS
authors.lastname: Huang
authors.forename: H-S
authors.initials: HS
authors.lastname: Lee
authors.forename: M-C
authors.initials: MC
authors.lastname: Chou
authors.forename: Y-Y I
authors.initials: YY
authors.lastname: Shih
authors.forename: P-H
authors.initials: PH
authors.lastname: Tsai
authors.forename: M-H
authors.initials: MH
authors.lastname: Lin
authors.forename: C-Y
authors.initials: CY
authors.lastname: Lin
authors.forename: C-H
authors.initials: CH
authors.lastname: Lee
authors.forename: H-W
authors.initials: HW
authors.lastname: Chung
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D016118:Anterior Cruciate Ligament / Q000601:surgery; D000070598:Anterior Cruciate Ligament Injuries; D001169:Arthritis, Experimental / Q000473:pathology; D002358:Cartilage, Articular / Q000187:drug effects / Q000473:pathology*; D004195:Disease Models, Animal; D006820:Hyaluronic Acid / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D007270:Injections, Intra-Articular; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D020370:Osteoarthritis, Knee / Q000188:drug therapy* / Q000473:pathology; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D000276:Adjuvants, Immunologic; D006820:Hyaluronic Acid