Incrimination of anaerobic bacteria in the induction of
experimental colitis.
Garc[acute]ia-Lafuente, A., M. Antol[acute]in, F. Guarner, E. Crespo,
A. Salas, P. Forcada, M. Laguarda, J. Gavald[acute]a, J. A. Baena, J.
Vilaseca, and J. R. Malagelada.
Digestive System Research Unit, Microbiology, Medicine and Surgery,
Hospital General Vall d'Hebron, and Department of Pathology, Hospital
Mutua Terrasa, Barcelona, Spain
APStracts 3:0143G, 1996.
Commensal bacteria may participate in the pathogenesis of bowel
inflammation. We studied the role of bacteria from the rat colonic
flora on transmural inflammation induced by trinitrobenzenesulfonic
acid. First, bacterial translocation to the colonic wall after
induction of colitis was assessed by microbiological and histological
methods. Second, rats with a colonic segment excluded from fecal
transit were prepared for recolonization with preselected bacteria,
and used to test the effects of different species on inflammation
(eicosanoid release, tissue myelo peroxidase) and damage (histology).
Six strains (3 aerobes and 3 anaerobes) were identified in colonic
tissue 24 h after induction of colitis. Acridine staining showed
bacteria in necrotic areas of the mucosa and invading the submucosa.
Rats with excluded colon and sterile culture of luminal washings
showed mild inflammation and low mucosal damage in response to
trinitrobenzenesulfonic acid. Rats colonized with anaerobes showed
significantly higher eicosanoid release than rats colonized with
aerobes only. Moreover, submucosal lesions were mostly observed in
rats with anaerobes. Our findings suggest that colonic anaerobes play
a key role in transmural inflammation.
Received 21 February 1996; accepted in final form 9 July 1996.
APS Manuscript Number G69-6.
Article publication pending Am. J. Physiol. (Gastrointest. Liver
Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 4 August 1996