Intestinal tight junction in allograft after small bowel transplantation

INTRODUCTION: In the intestinal physical barrier, tight junctions between intestinal epithelial cells play a central role. There is increasing evidence that rejection after small bowel transplantation promotes intestinal barrier injury to allografts. Our aim was to study the morphological changes of tight junctions in allografts during rejection. METHODS: Small bowel transplantation was performed using the F344 to Lewis rat model. Animals were divided into three groups: isogeneic controls, acute rejection group, and chronic rejection group. Allograft rejection was characterized by hemotoxylin and eosin staining of mucosal tissue sections. Tight junctions in grafts were investigated by transmission electron microscopy. RESULTS: Acutely rejected allografts showed severe mucosal injury and completely loosened tight junctions, while chronically rejected allografts revealed less mucosal injury and remained with partial integrity of their tight junctions. CONCLUSION: Our study demonstrated for the first time the morphological alterations of tight junctions in allograft mucosa during acute and chronic rejections, suggesting disruption of tight junctions was relative to the intestinal inflammatory processes.