MULTIPLE BOWEL ATRESIAS AFTER SYNGENEIC FETAL SMALL-BOWEL TRANSPLANTATION IN RATS

Purpose: The aim of this study was the assessment of atresia formation after syngeneic fetal small bowel transplantation (SBTx) to clarify i ts pathogenesis.Methods: Seventy Lewis rat fetuses (gestational age, 1 8 to 19 days) were obtained by hysterotomy, and a 30-mm long section o f small bowel was excised from each fetus. Each bower graft was then t ransplanted into the space between the peritoneum and the rectus abdom inis in 70 adult Lewis rats to expose the grafts to ischemic stress. T ransplantation was successful in 63 of 70 grafts (90%). Successfully t ransplanted bowel grafts were harvested for macroscopic and microscopi c examination 10 days posttransplantation. Results: Of the successfull y transplanted grafts, only two (3%) were atresia free; 127 atretic se gments were found in the remaining 61 grafts. Twenty-four grafts (38%) had a single atresia comprised of membranous stenosis (MS) in two, me mbranous atresia (MA) in 10, and blind ends (BEs) with or without a co nnecting tissue remnant in 12. Thirty-seven grafts (59%) had multiple atresias, comprised of MS, MA, or both in six, BEs alone in seven, and a combination of BEs with MS or MA in 24. Conclusions: Our model is t he first to succeed in inducing experimentally membranous stenosis and a high incidence (59%) of multiple atresias. These results suggest th at bowel ischemia is responsible for multiple bowel atresia formation. J Pediatr Surg 33:896-898. Copyright (C) 1998 by W.B. Saunders Compan y.