The immediate response of jejunal mucosa to small bowel heterotopic allotransplatation in rats

The course of histopathological alterations within jejunal graft architecture during the initial adaptation phase in the host body was investigated. Graft tissues were compared to the intestinal tissues of the recipients. This study demonstrates: (1) renewal of intestinal epithelial lining in the graft biopsies during initial hours after transplantation is more likely caused by migration and extension of remaining epithelial cells than by their increased mitotic division. (2) Distinct decrease in histopathological injury was observed in transplanted grafts after 6 h, but the morphometrical parameters, particularly villus height and wall thickness, remained altered. (3) Significant decrease in apoptotic cell death in the epithelial lining within 6 h of graft recirculation was accompanied by no effect on apoptosis levels of the cells in lamina propria connective tissue. (4) Although the apoptosis level in the connective tissue cells was not modulated in the grafts within the first hour after transplantation, caspase-3 dependent apoptosis was decreased significantly.