title: Colonoscopy in rats: An endoscopic, histological and tomographic study.
abstract: OBJECTIVE
  To describe colon anatomy with colonoscopy and computed tomography (CT) to develop a rat model for future studies of therapeutic colonoscopy.
  
  
  METHODS
  Eighteen male Sprague-Dawley rats, on average 400-420 g, underwent total colonoscopy, CT and histological examination. Colonoscopy was performed after bowel preparation with a baby upper gastrointestinal endoscopy with an outer diameter of 6.7 mm. CT obtained a 3D image of total colon after a rectal enema with radiological contrast. Macroscopic and microscopic examinations were examined with a conventional technique (hematoxylin and eosin). Colonic wall thickness, length and diameter measurements were taken from the anus, 3, 7, 14 and 20 cm from the anal margin.
  
  
  RESULTS
  The median colonoscope depth was 24 cm (range 20-28 cm). Endoscopic and tomographic study of colon morphology showed an easy access with tubular morphology in the entire left colon (proximal left colon and rectum). Transverse colon was unapparent on colonoscopy. Right colon, proximal to the splenic flexure, was the largest part of the colon and assumed saccular morphology with tangential trabecula. Radiological measurements of the colonic length and diameter substantiate a subdivision of the right colon into two parts, the cecum and distal right colon. In addition, histological measurement of the colonic wall thickness confirmed a progressive decrease from rectum to cecum. The muscular layer was thinner in the proximal left colon.
  
  
  CONCLUSIONS
  The combination of colonoscopy, tomography and histology leads to a better characterization of the entire colon. These data are important for deciding when to perform endoscopic resections or when to induce perforations to apply endoscopic treatments.
authors.affiliation: Ramon Bartolí, Gemma Ódena, Vicente Lorenzo-Zúñiga, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBEREHD), 08916 Badalona, Spain.
authors.forename: Ramon
authors.initials: R
authors.lastname: Bartolí
authors.forename: Jaume
authors.initials: J
authors.lastname: Boix
authors.forename: Gemma
authors.initials: G
authors.lastname: Odena
authors.forename: Napoleón D
authors.initials: ND
authors.lastname: De la Ossa
authors.forename: Vicente Moreno
authors.initials: VM
authors.lastname: de Vega
authors.forename: Vicente
authors.initials: V
authors.lastname: Lorenzo-Zúñiga
keywords: Colon anatomy; Colonoscopy; Histological measurements; Rat; Tomography