Endoscopic and radiographic evaluation of the murine colon

Abstract

Endoscopic and radiographic techniques have not been widely applicable in the evaluation of chemically induced murine colon cancer. The authors investigated methods of cleansing the rat colon and refined endoscopic and radiographic techniques. They compared total colonoscopy (TC) and air-contrast (ACBE) and single-contrast barium enema (SCBE) findings with those obtained at necropsy in rats with 1,2-dimethylhydrazine (DMH)-induced colon cancer. Gastrograffin enemas with bisacodyl suppositiories showed complete evacuation of solid feces. Sprague-Dawley rats treated with DMH had their colons cleansed and then underwent TC (5.0-mm Olympus bronchoscope) and either SCBE or ACBE. Colonoscopy and ACBE were equally sensitive (81.5% and 76.3%, respectively), although SCBE was significantly insensitive in identifying lesions (P less than 0.001). This study demonstrates that: (1) mechanical cleansing of the rat colon is feasible, (2) TC and barium radiology can be done routinely after mechanical cleansing, and (3) TC and double-contrast BE are sensitive in identifying colon lesions. These techniques will provide a means for manipulation of murine tumors and in vivo surveillance.

Development of a total colonoscopy rat model with endoscopic submucosal injection of the cecal wall

“…In fact, the former fails to produce a localized solid tumor before resection is carried out, whereas the latter entails a laparotomy. A possible solution was presented 15 years ago when Hull et al [7] showed that it was feasible to perform bowel prep and TC on rats. The authors successfully performed TC on 37 of 39 rats with a pediatric bronchoscope.…”

“…A previous study has shown that the long murine cecum provides a model for resection, which avoids the need for an anastomosis [1]. Another study showed that total colonoscopy (TC) is feasible in rats [7]. This indicates that a murine model with TC would be ideal for accessing the cecum for mucosal tumor induction.…”

Experimental Small Animal Colonoscopy

“…Colonoscopy has been successfully adapted for use in rat models. Using modified bronchoscopes (Hull et al, 1990) or other small-caliber flexible endoscopes (Haughn et al, 2006), total colonoscopy of the rat has been performed successfully, as well as other variations of this procedure (Zhang et al, 1994). Colonoscopy in mice was first attempted with a pediatric cystoscope with good results, although because of anatomic and instrumental limitations, the entire colon to the cecum could not be visualized (Huang et al, 2002).…”

Colonoscopy with mucosal biopsies in young rats: A model for experimental gastroenterology

“…Several studies have reported on attempts to perform colonoscopy in rats (1)(2)(3)(4)(5)(6)(7)(8)(9). However, in these studies, the rats were either large and old, the bowel was not optimally prepared, a total colonoscopy was not performed or no biopsies were taken.…”