Morphological and physiological changes of interstitial cells of Cajal after small bowel transplantation in rats.

Intestinal dysmotility has been reported to be associated with a decreased number of interstitial cells of Cajal (ICCs). However, the chronological changes in ICCs after small bowel transplantation (SBT) have not yet been elucidated. In this study, we aimed to evaluate the chronological change of ICCs after SBT. Orthotopic syngeneic SBT was performed in rats. Graft specimens were obtained at postreperfusion, and on 1, 3, 7, 14, and 30 postoperative day (POD). Thereafter, immunohistochemical staining was performed and the spontaneous contractions measured. During the initial period after SBT, the temporal impairment of ICCs was found. In an immunohistochemical study, c-Kit-positive cells appeared to decrease on POD 0, 1, and 3. Thereafter, the number of cells increased gradually up to POD 7. In contrast, the recovery of the spontaneous contractile amplitude took more time. The frequency of the electrical signal was preserved at almost exactly the same levels throughout this experimental period. Although the network of ICCs was found to be temporarily impaired after SBT in an immunohistochemical examination, this change was reversible. Moreover, the recovery of the function of the intestinal motility associated with ICCs was delayed after the early postoperative period.