title: Tissue interleukin 1 and interleukin-1 receptor antagonist expression in enterocolitis in resistant and susceptible rats.
abstract: OBJECTIVE
  Subserosal injection of purified group A streptococcal peptidoglycan-polysaccharide (PG-APS) induces chronic relapsing granulomatous enterocolitis and systemic inflammation in susceptible inbred Lewis rats but only transient intestinal injury in Buffalo and Fischer rats. Cecal interleukin 1 (IL-1) and IL-1 receptor antagonist (IL-1ra) expression was measured in inbred rats displaying differential susceptibility to experimental enterocolitis.
  
  
  METHODS
  The ileum and cecum of Lewis, Buffalo, and Fischer rats were subserosally injected with purified PG-APS or albumin. IL-1 and IL-1ra messenger RNA (mRNA) and protein (IL-1 only) were measured 1 or 27 days later. PG-APS-injected Lewis rats were treated with recombinant human IL-1ra. Kinetics of IL-1 and IL-1ra mRNA expression were studied in peritoneal cells.
  
  
  RESULTS
  All rats strains developed acute inflammation with increased cecal concentrations of IL-1 beta and IL-1ra mRNA. Lewis rats developed chronic enterocolitis and had higher IL-1 and IL-1ra mRNA tissue levels than Buffalo or Fischer rats, which displayed no chronic inflammation. IL-1 beta and IL-1ra were produced by submucosal granulomas and correlated with inflammation. IL-1 alpha protein levels paralleled IL-1 beta mRNA expression. IL-1ra treatment attenuated acute and chronic enterocolitis, adhesions, and arthritis. PG-APS induced IL-1 and IL-1ra expression in peritoneal cells from Lewis and Fischer rats.
  
  
  CONCLUSIONS
  Bacterial cell wall polymers stimulate IL-1 and IL-1ra expression in vivo and in vitro. These counterbalancing cytokines are increased in experimental enterocolitis and have important immunoregulatory roles in intestinal inflammation.
authors.affiliation: Department of Internal Medicine, University of North Carolina at Chapel Hill.
authors.forename: R D
authors.initials: RD
authors.lastname: McCall
authors.forename: S
authors.initials: S
authors.lastname: Haskill
authors.forename: E M
authors.initials: EM
authors.lastname: Zimmermann
authors.forename: P K
authors.initials: PK
authors.lastname: Lund
authors.forename: R C
authors.initials: RC
authors.lastname: Thompson
authors.forename: R B
authors.initials: RB
authors.lastname: Sartor
mesh_terms: D000818:Animals; D002432:Cecum / Q000378:metabolism; D004760:Enterocolitis / Q000235:genetics* / Q000378:metabolism* / Q000473:pathology; D005260:Female; D020022:Genetic Predisposition to Disease; D007375:Interleukin-1 / Q000235:genetics / Q000378:metabolism*; D017737:Macrophages, Peritoneal / Q000187:drug effects; D011135:Polysaccharides, Bacterial / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011915:Rats, Inbred BUF; D011916:Rats, Inbred F344; D011917:Rats, Inbred Lew; D017472:Receptors, Interleukin-1 / Q000037:antagonists & inhibitors* / Q000235:genetics; D011994:Recombinant Proteins; D013297:Streptococcus pyogenes
chemical_list: D007375:Interleukin-1; D011135:Polysaccharides, Bacterial; D012333:RNA, Messenger; D017472:Receptors, Interleukin-1; D011994:Recombinant Proteins; C036112:streptococcal polysaccharide group A