Evidence of Secondary Neuronal Intestinal Dysplasia in a Rat Model of Chronic Intestinal Obstruction

Experimental Models of Partial Intestinal Obstruction in Young Mice: Establishment, and Evaluation

BACKGROUND

Partial small bowel obstruction (SBO) is a common, potentially hazardous, surgical entity caused by numerous factors in humans. A number of techniques have been reported as efficient to simulate partial SBO in murine models. However, there is little data concerning their long-term survival. Our study presents a novel technique and evaluates its long-term efficiency compared with other commonly used techniques.

MATERIALS AND METHODS

Sixty C57BL/6 mice aged 6 to 8 wk were randomly divided into five intervention groups: ligation, intestinal ring, partial ligation, microclips, and the novel triple suture technique. The ring groups were subdivided into narrow, medium, and wide ring and partial ligation groups were subdivided at 1/3, 1/2, and 2/3 of the lumen. Survival cutoff time was set at 4 wk. Animals were then euthanized and small bowel muscle layer thickness was histopathologically evaluated.

RESULTS

None of the animals of the ligation and the ring groups reached the cutoff survival time. The mortality rate of the partial ligation and the microclips groups at the 4-week period were 33.3% and 0%, respectively. However, elimination of the performed intervention was revealed at the time of euthanasia and no alterations of the muscle layer were revealed at histopathology. The "triple suture" group had a survival rate of 90% until euthanasia and the sutures were apparent in all cases. Macroscopic evaluation showed small to mild proximal lumen dilatation in 6 of 10 animals. Histopathological evaluation of the specimens confirmed the partial obstruction.

CONCLUSIONS

The "triple suture" technique is a new, robust, reliable, and inexpensive technique for experimental long-standing partial SBO, with very low mortality.

Intestinal neuronal dysplasia-like histopathology in infancy

The present patient was delivered at a gestational age of 27 weeks. She had abdominal bloating with symptoms of respiratory distress. We suspected Hirschsprung disease (HD) or small intestinal stricture, but examinations were not definitive. Exploratory laparotomy was performed at 97 days of age. Intraoperative findings showed no evidence of small intestinal stricture or changes in intestinal caliber. A transanal drainage tube was inserted, and decompression therapy and intestinal lavage were started. Rectal mucosal biopsy was performed at 184 days of age, and HE and acetylcholinesterase staining showed intestinal neuronal dysplasia (IND)-like pathological findings. At 15 months, giant ganglia were no longer present on follow-up rectal mucosal biopsy, and the pathological diagnosis was normoganglionosis. It should be recognized that while the enteric nervous system is developing, IND-like pathological findings may be seen as a pathological condition during the maturation process.