Determination of the Ideal Preparation for Colonoscopy in a Rat Model

Background: Quality bowel preparation is essential to examine the entire colon adequately. No trials comparing different purgative regimens are available in animal models. The aim was to compare 5 methods for bowel cleansing to develop a rat model to study therapeutic colonoscopy. Methods: Twenty-five rats were assigned to one of 5 regimens: (1) high-volume polyethylene glycol electrolyte solution (HV-PEG-ES, 40 mL); (2) low-volume PEG-ES (LV-PEG-ES, 20 mL); (3) high-volume PEG-ES + ascorbic acid (HV-PEG-ES + AA, 20 mL); (4) LV-PEG-ES + AA, 10 mL; (5) rectal enema with saline solution (RE-SS). Bowel preparation quality was rated by total colonoscopy. Results: RE-SS is the best regime for left colon cleansing, whereas HV-PEG-ES and HV-PEG-ES + AA solutions resulted in significantly better cleansing in the whole colon. HV-PEG-ES + AA regimen needed less volume, and administration was easier. Conclusions: A total of 20 mL of PEG-ES + AA before colonoscopy is the best regimen to explore the whole colon, whereas to explore the left colon RE-SS is adequate.