INTRODUCTION: INTRODUCTION:A rat model of long-term colonic intubation has been developed to facilitate the in vivo study of colonic biology. This study aims to characterize this model.
METHODS: METHODS:The effects of intubation and sham surgery on animal behavior and weight gain were measured and compared with unoperated controls. The reproducibility of the model was assessed by comparing complication and failure rates for three operators. The distribution and excretion of infused materials were studied using radiology and gas chromatography of feces, respectively. The effects of the colonic tube and infusions on the mucosa were assessed histologically.
RESULTS: RESULTS:There was about 10 percent weight loss postoperatively, more marked in those rats undergoing more extensive surgery. Subsequent weight gain was similar in all groups, and no behavioral effects of surgery were noted. There were no differences in histologic appearances or proliferative indices among the groups. All three operators had similar complication and tube dislodgement rates. Radiologic examination showed even distribution of infusate regardless of fecal consistency. Infusion through the two tubes allowed the cecum and the distal bowel to be targeted differentially. The infusions did not alter the consistency of the fecal pellets or induce defecation. Gas chromatography at various time points after butyrate infusion showed a small, but statistically insignificant, rise in fecal excretion, representing less than 10 percent of the infused butyrate.
CONCLUSIONS: CONCLUSIONS:A highly reproducible in vivo rat model, with an experimental life span of five to six weeks, has been achieved. Biological agents can be accurately delivered via the colonic tubes and are retained in the colonic segment of interest. This intubation model should provide a valuable tool in the future for in vivo studies of colonic biology.
© The ASCRS 2002