Analysis of mucosal regeneration and the expression profile of heat shock protein 70 in the isolated small bowel segment.

To investigate the mechanisms underlying the regeneration of the denervated small bowel segment from ischemic injury, we examined the heat shock protein 70 (HSP70) expression profile and compared it to the histopathological and proliferative changes seen in an isolated bowel segment using a rabbit model. Two weeks following the small bowel segment transplantation to the subcutaneous space, the vascular pedicle was sectioned. Next, the rabbits were divided into three groups based on the collection time of the isolated bowel segment (3, 7, and 14 days for Groups A, B, and C, respectively). The unsectioned small bowel segment was utilized as a control for each group. Histological studies showed that no experimental group recovered from mucosal injury. The bromodeoxyuridine labeling index showed that the more severe mucosal injury group had the highest bromodeoxyuridine incorporation. In the experimental groups, HSP70 immunoreactivity was intensely seen in the regenerating epithelial cells and inflammatory cells. In the control mucosa, HSP70 immunoreactivity was weakly seen in the subepithelial stromal tissue, crypt cells and not in epithelial cells. The present study shows that the isolated bowel segment requires longer periods for regeneration from ischemic injury and HSP70 may play an important role during the regeneration process.