title: Immobilization aggravates cartilage damage during antigen-induced arthritis in mice. Attachment of polymorphonuclear leukocytes to articular cartilage.
abstract: The early and late effects of short-term immobilization on arthritic joints have been studied. Knee joints of mice in which an antigen-induced unilateral arthritis was elicited were immobilized in extension for 3, 5, and 7 days. After 5 and 7 days' immobilization, arthritis was significantly more severe. More leukocytes infiltrated the periarticular tissues and more cellular exudate was found in the joint space. A striking observation was that large numbers of polymorphonuclear leukocytes (PMN) attached to the surface of the cartilage, a phenomenon not found in mobile arthritic joints. Electron-microscopy confirmed PMN adhesion and showed severe ruffling of the cartilage surface under immobilized conditions. Further examination of factors determining PMN sticking revealed that attachment is rapid when the cartilage surface is already damaged, and that retained immune complexes and complement play a pivotal role. The late effects of immobilization were studied after a remobilization period of 2 weeks. Enhanced matrix depletion and chondrocyte death persisted in arthritic joints that were previously immobilized for 5 and 7 days, and the latter also showed significantly increased osteophyte formation. Although these results are speculative for the human situation, this study indicates that treatment of arthritic joints by complete rest should be applied with caution.
authors.affiliation: Department of Rheumatology, University Hospital St. Radboud, Nijmegan, The Netherlands.
authors.forename: P L
authors.initials: PL
authors.lastname: van Lent
authors.forename: L
authors.initials: L
authors.lastname: van den Bersselaar
authors.forename: L B
authors.initials: LB
authors.lastname: van de Putte
authors.forename: W B
authors.initials: WB
authors.lastname: van den Berg
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000502:physiology; D000941:Antigens / Q000502:physiology*; D001168:Arthritis / Q000209:etiology*; D001169:Arthritis, Experimental / Q000209:etiology* / Q000473:pathology; D002358:Cartilage, Articular / Q000473:pathology* / Q000503:physiopathology / Q000648:ultrastructure; D002448:Cell Adhesion / Q000502:physiology; D003165:Complement System Proteins / Q000502:physiology; D004195:Disease Models, Animal; D007103:Immobilization / Q000009:adverse effects*; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D009504:Neutrophils / Q000473:pathology / Q000502:physiology / Q000648:ultrastructure; D015054:Zymosan / Q000494:pharmacology
chemical_list: D000936:Antigen-Antibody Complex; D000941:Antigens; D003165:Complement System Proteins; D015054:Zymosan