title: Prophylactic systemic P2X7 receptor blockade prevents experimental colitis.
abstract: BACKGROUND
  The P2X7 receptor (P2X7-R) is a non-selective adenosine triphosphate-gated cation channel present in epithelial and immune cells, and involved in inflammatory response. Extracellular nucleotides released in conditions of cell stress or inflammation may function as a danger signal alerting the immune system from inflammation. We investigated the therapeutic action of P2X7-R blockade in a model of inflammatory bowel disease.
  
  
  METHODS
  Rats with trinitrobenzene sulfonic (TNBS) acid-induced colitis were treated with the P2X7-R antagonists A740003 or brilliant blue G (BBG) through intra-peritoneal (IP) or intra-colonic (IC) injection prior to colitis induction. Clinical and endoscopic follow-up, histological scores, myeloperoxidase activity, densities of collagen fibers and goblet cells were evaluated. P2X7-R expression, NF-kappa B and Erk activities, and densities of T-cells and macrophages were analyzed by immunoperoxidase. The inflammatory response was determined by measuring inflammatory cytokines in cultures of colon explants, by enzyme-linked immunosorbent assay. Colonic apoptosis was determined by the TUNEL assay.
  
  
  RESULTS
  IP-BBG significantly attenuated the severity of colitis, myeloperoxidase activity, collagen deposition, densities of lamina propria T-cells and macrophages, while maintaining goblet cell densities. IP-BBG inhibited the increase in P2X7-R expression in parallel with apoptotic rates. TNF-α and interleukin-1β stabilized in low levels, while TGF-β and interleukin-10 did not change following IP-BBG-therapy. Colonic NF-kappa-B and Erk activation were significantly lower in IP-BBG-treated animals. Prophylactic IP-A740003 also protected rats against the development of TNBS-colitis.
  
  
  CONCLUSIONS
  Prophylactic systemic P2X7-R blockade is effective in the prevention of experimental colitis, probably due to a systemic anti-inflammatory action, interfering with a stress-inflammation amplification loop mediated by P2X7-R.
authors.affiliation: Departamento de Clínica Médica, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-913, Brazil; Laboratório de Imunologia Celular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil; Programa de Imunobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro 21941-590, Brazil.
authors.forename: Carla Caldas
authors.initials: CC
authors.lastname: Marques
authors.forename: Morgana T
authors.initials: MT
authors.lastname: Castelo-Branco
authors.forename: Rodrigo G
authors.initials: RG
authors.lastname: Pacheco
authors.forename: Fernanda
authors.initials: F
authors.lastname: Buongusto
authors.forename: Alyson
authors.initials: A
authors.lastname: do Rosário
authors.forename: Alberto
authors.initials: A
authors.lastname: Schanaider
authors.forename: Robson
authors.initials: R
authors.lastname: Coutinho-Silva
authors.forename: Heitor S P
authors.initials: HS
authors.lastname: de Souza
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D003092:Colitis / Q000139:chemically induced / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D003106:Colon / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D020397:Goblet Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D007274:Injections, Intraperitoneal; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008297:Male; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D009195:Peroxidase / Q000235:genetics / Q000378:metabolism; D058920:Purinergic P2X Receptor Antagonists / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D058486:Receptors, Purinergic P2X7 / Q000235:genetics / Q000378:metabolism*; D012394:Rosaniline Dyes / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D014302:Trinitrobenzenesulfonic Acid
chemical_list: D000893:Anti-Inflammatory Agents; D016328:NF-kappa B; D058920:Purinergic P2X Receptor Antagonists; D058486:Receptors, Purinergic P2X7; D012394:Rosaniline Dyes; D014302:Trinitrobenzenesulfonic Acid; D003094:Collagen; D009195:Peroxidase; D048049:Extracellular Signal-Regulated MAP Kinases; C004692:coomassie Brilliant Blue
keywords: Apoptosis; Brilliant blue G; Innate immunity; P2X7-R; P2X7-R blockade; TNBS-induced colitis