title: All-trans retinoic Acid reduces joint adhesion formation: an experimental study in rats.
abstract: BACKGROUND
  Intra-articular adhesion is a common complication in post-surgical knees. The formation of post-surgical joint adhesion could lead to serious conditions. All-trans retinoic acid (ATRA) is a physiological metabolite of vitamin A that has a wide range of biological activities. The aim of the study was to verify the effects of (ATRA) in preventing adhesions in the post-operative rat knee.
  
  
  METHODS
  Eighty healthy adult male Wistar rats underwent femoral condyle-exposing surgery. After surgery, cotton pads soaked with the vehicle or various concentrations of ATRA (0.1%, 0.05%, 0.025%) were applied to the surgery site for 5 min. The post-surgical knee joints were fixed with micro-Kirschner wires in a flexed position for 4 weeks. The rats were killed 4 weeks after surgery. The effect of ATRA on the prevention of intra-articular adhesion was evaluated using histological analyses, hydroxyproline content, visual score, and inflammatory factor activity evaluation.
  
  
  RESULTS
  No obvious postoperative complications or signs of infection in the rats were observed. None of the rats died before the scheduled time. The rats in the 0.1% ATRA group showed better outcomes, as suggested by the visual scores, hydroxyproline contents, and inflammatory factors expressional levels, than the other 2 groups. The local application of 0.1% ATRA was able to suppress adhesions, collagen expression, and inflammatory activity in the post-surgical rat knees.
  
  
  CONCLUSIONS
  In the rat knee surgery model, the application of intra-articular ATRA was able to decrease intra-articular scar adhesion formation, collagen expression, and inflammatory activities. ATRA was found to work in a dose-dependent manner, with 0.1% being possible optimal concentration.
authors.affiliation: Department of Orthopedics, Pingjin Hospital, Logistics University of Chinese People's Armed Police Forces, Tianjin, China (mainland).
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Tianjin Medical University, Tianjin, China (mainland).
authors.forename: Chao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Tianjin Medical University, Tianjin, China (mainland).
authors.forename: Huan
authors.initials: H
authors.lastname: Cheng
authors.affiliation: Tianjin Medical University, Tianjin, China (mainland).
authors.forename: Patricia
authors.initials: P
authors.lastname: Douglas
authors.affiliation: Department of Orthopedics, Pingjin Hospital, Logistics University of Chinese People's Armed Police Forces, Tianjin, China (mainland).
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Wang
authors.affiliation: Department of Orthopedics, Tianjin Medical University, Taida Hospital, Tianjin, China (mainland).
authors.forename: Yun
authors.initials: Y
authors.lastname: Lu
mesh_terms: D000818:Animals; D001864:Bone Wires; D004305:Dose-Response Relationship, Drug; D005269:Femur / Q000601:surgery*; D006614:Hindlimb / Q000473:pathology*; D006652:Histological Techniques; D006909:Hydroxyproline / Q000378:metabolism; D007596:Joints / Q000473:pathology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D000267:Tissue Adhesions / Q000473:pathology* / Q000517:prevention & control*; D014212:Tretinoin / Q000008:administration & dosage / Q000494:pharmacology*
chemical_list: D014212:Tretinoin; D006909:Hydroxyproline