Abstract:

Objective To investigate the immunosuppression effect of successive composite tissue allotransplantation（SCTA）after previous parenchymatous organ transplantation in rats. Methods Left lungs from WKY rats were orthotopically transplanted into F344 rats, and cuff technique was employed for anastomoses of the left pulmonary vein, left pulmonary artery and main bronchus. F344 rats were subcutaneously injected with cyclosporine A (5 mg/kg) once every two days for 10 d after operation. Transplanted pulmonary function was assessed with respiratory rate. On the eleventh day after lung transplantation, 3 cm×3 cm abdominal musculocutaneous flaps harvested from Brown Norway rats were transplanted to F344 rats, and the abdominal flap vessels were connected to the femoral vessels. No further immunosuppression was administered following flap transplantion. Ten days after composite tissue allotransplantation (CTA), transplanted flaps and lung tissues were obtained for histopathological examinations, and rejection reaction was observed. Results The successful rates of lung transplantation, CTA and SCTA were 90%, 100% and 90% respectively. The respiratory rates increased from (61±10) times/min on day 10 after transplantation (immunosuppression for 10 d) to (75±15) times/min on day 20 after transplantation (immunosuppression withdrawl for 10 d). The allotransplanted lung exhibited typical signs of acute rejection, including both perivascular and diffuse lymphocytic infiltration. There was no acute rejection in abdominal flap autograft by histopathological observation, and the allotransplanted abdominal flaps had typical perivascular and diffuse lymphocytic infiltration after CTA. Conclusion SCTA rat model may facilitate the research of secondary CTA following primary parenchymatous organ transplantation and can be useful in developing future immunotherapeutic strategies.

Key words: successive transplantation, composite tissue allotransplantation, lung transplantation, rat model