title: Intra-articular decorin influences the fibrosis genetic expression profile in a rabbit model of joint contracture.
abstract: OBJECTIVE
  The goal of this study was to determine whether intra-articular administration of the potentially anti-fibrotic agent decorin influences the expression of genes involved in the fibrotic cascade, and ultimately leads to less contracture, in an animal model.
  
  
  METHODS
  A total of 18 rabbits underwent an operation on their right knees to form contractures. Six limbs in group 1 received four intra-articular injections of decorin; six limbs in group 2 received four intra-articular injections of bovine serum albumin (BSA) over eight days; six limbs in group 3 received no injections. The contracted limbs of rabbits in group 1 were biomechanically and genetically compared with the contracted limbs of rabbits in groups 2 and 3, with the use of a calibrated joint measuring device and custom microarray, respectively.
  
  
  RESULTS
  There was no statistical difference in the flexion contracture angles between those limbs that received intra-articular decorin versus those that received intra-articular BSA (66° vs 69°; p = 0.41). Likewise, there was no statistical difference between those limbs that received intra-articular decorin versus those who had no injection (66° vs 72°; p = 0.27). When compared with BSA, decorin led to a statistically significant increase in the mRNA expression of 12 genes (p < 0.01). In addition, there was a statistical change in the mRNA expression of three genes, when compared with those without injection.
  
  
  CONCLUSIONS
  In this model, when administered intra-articularly at eight weeks, 2 mg of decorin had no significant effect on joint contractures. However, our genetic analysis revealed a significant alteration in several fibrotic genes. Cite this article: Bone Joint Res 2014;3:82-8.
authors.affiliation: Mayo Clinic, 200First Street, Rochester, Minnesota, 55905, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Abdel
authors.forename: M E
authors.initials: ME
authors.lastname: Morrey
authors.forename: J D
authors.initials: JD
authors.lastname: Barlow
authors.forename: D E
authors.initials: DE
authors.lastname: Grill
authors.forename: C P
authors.initials: CP
authors.lastname: Kolbert
authors.forename: K N
authors.initials: KN
authors.lastname: An
authors.forename: S P
authors.initials: SP
authors.lastname: Steinmann
authors.forename: B F
authors.initials: BF
authors.lastname: Morrey
authors.forename: J
authors.initials: J
authors.lastname: Sanchez-Sotelo
keywords: Arthrofibrosis; Decorin; Genetic expression; Joint contractures; Rabbit model