title: Histomorphometry in antigen-induced arthritis of the rabbit temporomandibular joint.
abstract: BACKGROUND
  Juvenile idiopathic arthritis (JIA) of the temporomandibular joint (TMJ) can cause severe growth disturbances of the craniomandibular system. Antigen-induced arthritis (AIA) of the rabbit TMJ is simulating the inflammatory process of the TMJ in JIA. The aim of this study was to investigate the effect of a systemic administration of the tumor necrosis factor-alpha (TNF-α) antagonist etanercept on AIA in rabbits by means of three different histological staining methods.
  
  
  METHODS
  After sensitization, a bilateral arthritis of the TMJ was induced and maintained by repeated intra-articular administrations of ovalbumin in 12 New Zealand white rabbits aged 10 weeks. From the 13th week of age, 6 of the 12 rabbits received weekly subcutaneous injections of etanercept, and the other 6 animals remained without therapy. Another 6 animals served as controls, receiving no treatment or intra-articular injections at all. After euthanasia at the age of 22 weeks, all TMJs were retrieved en bloc. Sagittal sections were cut and stained with hematoxylin-eosin (H-E), Safranin-O for the evaluation of the Mankin score, and tartrate-resistant acid phosphatase (TRAP).
  
  
  RESULTS
  In the arthritis group, a chronic inflammation with degeneration of the articular cartilage was visible. In the etanercept group, the signs of cartilage degeneration were significantly reduced but present. In contrast, the joints in the control group were inconspicuous. A strong correlation between the Mankin score and TRAP-positive cells could be found.
  
  
  CONCLUSIONS
  Antigen-induced arthritis causes severe damage in the TMJ of young rabbits. An improvement seems to be achievable by a systemic administration of etanercept.
authors.affiliation: Department of Orthodontics, Dentofacial Orthopedics and Pedodontics, Center for Dental and Craniofacial Sciences, Charité - Universitätsmedizin Berlin, Berlin, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Rafayelyan
authors.forename: R J
authors.initials: RJ
authors.lastname: Radlanski
authors.forename: K
authors.initials: K
authors.lastname: Minden
authors.forename: N
authors.initials: N
authors.lastname: Pischon
authors.forename: P-G
authors.initials: PG
authors.lastname: Jost-Brinkmann
authors.forename: T M
authors.initials: TM
authors.lastname: Präger
mesh_terms: D000135:Acid Phosphatase / Q000032:analysis; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000627:therapeutic use*; D001169:Arthritis, Experimental / Q000188:drug therapy* / Q000473:pathology; D001171:Arthritis, Juvenile / Q000188:drug therapy* / Q000473:pathology; D015415:Biomarkers / Q000032:analysis; D002358:Cartilage, Articular / Q000473:pathology; D004396:Coloring Agents; D004195:Disease Models, Animal; D000068800:Etanercept / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D005620:Freund's Adjuvant / Q000008:administration & dosage; D007270:Injections, Intra-Articular; D007279:Injections, Subcutaneous; D007527:Isoenzymes / Q000032:analysis; D008335:Mandibular Condyle / Q000473:pathology; D010010:Osteoclasts / Q000473:pathology; D010047:Ovalbumin / Q000008:administration & dosage; D010619:Phenazines; D011817:Rabbits; D011897:Random Allocation; D000071681:Tartrate-Resistant Acid Phosphatase; D013705:Temporomandibular Joint Disorders / Q000188:drug therapy* / Q000473:pathology; D013997:Time Factors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D004396:Coloring Agents; D007527:Isoenzymes; D010619:Phenazines; D010047:Ovalbumin; D005620:Freund's Adjuvant; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase; D000068800:Etanercept; C009195:safranine T
keywords: antigen-induced arthritis; etanercept; histology; rabbit; temporomandibular joint