Formation of microchimerism in rat small bowel transplantation by splenocyte infusion

AIM: To investigate the effect of donor splenocyte infusion combined with cyclosporine A (CsA) on rejection of rat small bowel transplantation (SBT). METHODS: Male Sprague-Dawley (SD) rats and female Wistar rats weighing 230-270 g were used as donors and recipients respectively in the study. Heterotopic small bowel transplantation was performed. The rats were divided into three groups: group one receiving allotransplantation (SD rarr Wistar), group two receiving allotransplantation (SD rarr Wistar) + donor splenocyte infusion, group three receiving allotransplantation (SD rarr Wistar) + donor splenocyte infusion + CsA followed by CsA 10 mg/kg per day after transplantation, in which recipient Wistar rats were injected with 2 x 10(8) SD splenocytes 28 d before transplantation, and treated with CsA after transplantation. Finally, the specific DNA fragment of donor Y chromosome was detected in recipient peripheral blood and skin by PCR. The survival time after small bowel transplantation was observed. Gross and histopathological examinations were performed. RESULTS: The survival time after small bowel trans-plantation was 7.1 +/- 1.2 d in group 1, 18.4 +/- 3.6 d in group 2 and 31.5 +/- 3.1 d in group 3. The survival time was significant longer (P < 0.01) in group 3 than in groups 1 and 2. The gross and histopathological examination showed that the rejection degree in group 3 was lower than that in groups 1 and 2. CONCLUSION: Donor splenocyte infusion combined with CsA decreases remarkably the rejection and prolongs the survival time after rat small bowel transplantation.