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→Wistar）, group two receiving allotransplantation （SD→Wistar） ＋ donor splenocyte infusion, group three receiving allotransplantation （SD →Wistar） ＋ donor splenocyte infusion ＋ CsA followed by CsA 10 mg/kg per day after transplantation, in which recipient Wistar rats were injected with 2 ×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 transplantation 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.