title: Colonic insufflation with carbon monoxide gas inhibits the development of intestinal inflammation in rats.
abstract: BACKGROUND
  The pathogenesis of inflammatory bowel disease (IBD) is complex, and an effective therapeutic strategy has yet to be established. Recently, carbon monoxide (CO) has been reported to be capable of reducing inflammation by multiple mechanisms. In this study, we evaluated the role of colonic CO insufflation in acute colitis induced by trinitrobenzene sulfonic acid (TNBS) in rats.
  
  
  METHODS
  Acute colitis was induced with TNBS in male Wistar rats. Following TNBS administration, the animals were treated daily with 200 ppm of intrarectal CO gas. The distal colon was removed to evaluate various parameters of inflammation, including thiobarbituric acid (TBA)-reactive substances, tissue-associated myeloperoxidase (MPO) activity, and the expression of cytokine-induced neutrophil chemoattractant (CINC)-1 in colonic mucosa 7 days after TNBS administration.
  
  
  RESULTS
  The administration of TNBS induced ulceration with surrounding edematous swelling in the colon. In rats treated with CO gas, the colonic ulcer area was smaller than that of air-treated rats 7 days after TNBS administration. The wet colon weight was significantly increased in the TNBS-induced colitis group, which was markedly abrogated by colonic insufflation with CO gas. The increase of MPO activity, TBA-reactive substances, and CINC-1 expression in colonic mucosa were also significantly inhibited by colonic insufflation with CO gas.
  
  
  CONCLUSIONS
  Colonic insufflation with CO gas significantly ameliorated TNBS-induced colitis in rats. Clinical application of CO gas to improve colonic inflammatory conditions such as IBD might be useful.
authors.affiliation: Molecular Gastroenterology and Hepatology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kawaramachi-Hirokoji, Kamigyo-ku, Kyoto, 602-8566, Japan. ynaito@koto.kpu-m.ac.jp.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Takagi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Naito
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Uchiyama
authors.forename: Toshimitsu
authors.initials: T
authors.lastname: Okuda
authors.forename: Takahiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Hisato
authors.initials: H
authors.lastname: Tsuboi
authors.forename: Katsura
authors.initials: K
authors.lastname: Mizushima
authors.forename: Osamu
authors.initials: O
authors.lastname: Handa
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Yagi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ichikawa
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Yoshikawa