title: Serum Mast Cell Tryptase as a Marker of Posttraumatic Joint Contracture in a Rabbit Model.
abstract: OBJECTIVE
  Mast cells have been identified as key mediators of posttraumatic joint contracture, and stabilizing medications (ketotifen) have been shown to decrease contracture severity. Serum mast cell tryptase (SMCT) levels are used clinically to monitor mast cell-mediated conditions. The goals of this study were to determine if SMCT levels are elevated in the setting of joint contracture, if they can be decreased in association with ketotifen therapy, and if they correlate with contracture severity.
  
  
  METHODS
  This study used a previously developed rabbit model in which 39 animals were divided into 4 groups: operatively created joint contracture (ORC, n = 13), operatively created contracture treated with ketotifen at 2 doses (KF0.5, n = 9; KF1.0, n = 9), and healthy rabbits (NC, n = 8). Range of motion measures were performed at 8 weeks after the surgery. Serum samples were collected on postoperative days 1, 3, 5, 7, 21, 35, and 49. SMCT levels were measured using a rabbit-specific enzyme-linked immunosorbent assay.
  
  
  RESULTS
  Levels of SMCT were highest in the operatively created joint contracture group and were significantly greater compared with both ketotifen groups (P < 0.001). Levels were highest at postoperative day 1 with a trend to decrease over time. A positive correlation between SMCT levels and contracture severity was observed in all operative groups (P < 0.05).
  
  
  CONCLUSIONS
  Levels of SMCT are elevated in the setting of joint contracture, decreased in association with ketotifen therapy, and positively correlated with contracture severity. This is the first study to establish a relationship between SMCT and joint injury. Measurement of SMCT may be valuable in identifying those at risk of posttraumatic joint contracture.
authors.affiliation: *Department of Surgery, University of Calgary, Calgary, Canada; †Department of Medicine, University of Alberta, Edmonton, Canada; ‡Department of Orthopaedic Surgery, Shanghai Jiao Tong University, Shanghai, China; and §Department of Orthopaedic Surgery, The General Hospital of People's Liberation Army Beijing, Beijing, China.
authors.forename: Michaela
authors.initials: M
authors.lastname: Kopka
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Monument
authors.forename: A Dean
authors.initials: AD
authors.lastname: Befus
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: David A
authors.initials: DA
authors.lastname: Hart
authors.forename: Paul T
authors.initials: PT
authors.lastname: Salo
authors.forename: Prism S
authors.initials: PS
authors.lastname: Schneider
authors.forename: Cun-Yi
authors.initials: CY
authors.lastname: Fan
authors.forename: Xiangdang
authors.initials: X
authors.lastname: Liang
authors.forename: Alexandra
authors.initials: A
authors.lastname: Garven
authors.forename: Kevin A
authors.initials: KA
authors.lastname: Hildebrand
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000097:blood; D003286:Contracture / Q000097:blood* / Q000175:diagnosis*; D007718:Knee Injuries / Q000097:blood* / Q000175:diagnosis*; D011817:Rabbits; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D053802:Tryptases / Q000097:blood*
chemical_list: D015415:Biomarkers; D053802:Tryptases