title: Experimental induction of arthritis in rats immunized with Escherichia coli 0:14 lipopolysaccharide.
abstract: OBJECTIVE
  Escherichia coli 0:14 (E. coli 0:14) induces arthritis in rabbits, mice and rats. This study was designed to investigate the effects of lipopolysaccharide (LPS) on the rat arthritis model induced by systemic injections of E. coli 0:14.
  
  
  METHODS
  The induction of arthritis in the ankles of rats immunized by subcutaneous injections with heat-killed E. coli 0:14 and its LPS was studied. The appearance and levels of serum IgM rheumatoid factor-like substance (RFLS) was also investigated. The localization of interleukin 1 (IL-1) and LPS in the ankle joints were investigated immunohistochemically.
  
  
  RESULTS
  The induction rate of arthritis in rats immunized with LPS was the same as that in rats immunized with E. coli. LPS and IL-1 were detected in synovial cells, infiltrating cells and some cells on pannus in arthritic joints. Anti-LPS IgM levels in rats immunized with E. coli were as high as those in rats immunized with LPS. RFLS levels in rats immunized with LPS increased more gradually than those in rats immunized with E. coli.
  
  
  CONCLUSIONS
  Our findings suggest that LPS induces arthritis resembling rheumatoid arthritis in rats. The detection of IL-1 in synovial cells in conjunction with LPS suggests that local stimulation of IL-1 production may play an important role in the induction of this experimental arthritis.
authors.affiliation: Department of Orthopaedic Surgery, Yokohama City University School of Medicine, Kanagawa, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Noyori
authors.forename: R
authors.initials: R
authors.lastname: Okamoto
authors.forename: T
authors.initials: T
authors.lastname: Takagi
authors.forename: A
authors.initials: A
authors.lastname: Hyodo
authors.forename: K
authors.initials: K
authors.lastname: Suzuki
authors.forename: T
authors.initials: T
authors.lastname: Koshino
mesh_terms: D000818:Animals; D001168:Arthritis / Q000139:chemically induced / Q000276:immunology*; D004731:Endotoxins / Q000276:immunology / Q000633:toxicity*; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D006965:Hyperplasia; D007114:Immunization; D007075:Immunoglobulin M / Q000097:blood; D007279:Injections, Subcutaneous; D007375:Interleukin-1 / Q000032:analysis; D008070:Lipopolysaccharides / Q000276:immunology / Q000633:toxicity*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012217:Rheumatoid Factor / Q000097:blood; D013583:Synovial Membrane / Q000737:chemistry / Q000473:pathology
chemical_list: D004731:Endotoxins; D007075:Immunoglobulin M; D007375:Interleukin-1; D008070:Lipopolysaccharides; C044101:endotoxin, Escherichia coli; D012217:Rheumatoid Factor