Portal Venous Drainage, The Drainage Of Pancreatic Juice, Intestinal Rat Pancreas Transplantation Model And The Pd-l1.ig United 1,25 (oh) <sub> 2 </ Sub> D <sub> 3 </ Sub> In Acute Graft Rejection Reaction The Role Of Experimental

Part I Development of a rat model of pancreaticoduodenal transplantation with portal venous drainage and enteric drainageObjective: To establish a model of pancreaticoduodenal transplantation with portal venous drainage and enteric drainage for basic research, which is near the physiologically normal function and eliminates hyperinsulinemia and reduces postoperative complications in the rat.Methods: SD rats served as donors and recipients. Diabetes was induced by a single intravenous injection of streptozocin (STZ) at dose of 50mg/kg of body weight. The nonfasting blood glucose and urine glucose of the rats were assayed before the inducement of DM and measured on alternate day after the injection of STZ. Only rats with nonfasting blood glucose exceeding 16.8mmol/L and the strong positive reaction of the urine glucose were selected as recipients. The whole pancreas duodenal transplantation model was adopted. The aortic segment of graft, including the celiac and superior mesenteric divergences, was end-to-side anastomosed with recipient abdominal aorta. While the donor portal was end-to-side anastomosed with the branch of recipient superior mesenteric vein. Enteric drainage was performed by side to side anastomosis between the donors duodenum and recipients jejunum. While the nonfasting blood glucose was less than 11.2mmol/L of recipients one day after transplantation, we thinked the transplantation was successfully.Results: A total of 45pancreas transplantation were performed, of which 38 survived more than 7d with normal blood glucose. The successful rate of transplantation was 86%. The donor operation consumed (51.25±3.86) min and the recipient operation consumed (55.62±2.89)min. The mean time used for artery anastomosis was about 11 min, and that for the vein anastomosis was about 9min, the mean cold ischemic time lasted about 38min.The mean value of blood glucose on d1,d3,d5 after transplantation separately were (4.89±0.79)mmol/L,(5.13±1.14)mmol/L and (5.82±1.39)mmol/L. The causes of death were thrombosis, infection, bleeding, and et al.Conclusion: The rat model of pancreaticoduodenal transplantation with portal venous drainage and enteric drainage is near the physiologically normal founction and can reduce the duration of ischemia during operation, which can be used to study the immunology and physiology of this graft. Part II Inhibition of Acute Allograft Rejection in Rat Pancreas Allograft Models by Combined Treatment with PD-L1.Ig and 1, 25-dihydroxyvitamin D₃Objective This study was conducted to investigate the effects of PD-L1.Ig combined with 1, 25(OH)₂D₃ on the acute rejection of pancreatic allograft in the rat model ,and the synergic effects of them in prolonging survival time of vascularized pancreatic allograft. Methods Pancreatic allograft from F344 rats was transplanted to Lewis recipients. Experimental animals were divided into four groups in random, 12 rats for each. Group A Negative control; Group B Intraperitoneal injection with PD-L1.Ig on day 0. 2. 4 after pancreas transplantation ; Group C consist of allograft recipients receiving daily intraperitoneal injections of 1,25-dihydroxyvitamin D₃ ; Group D animals were subjected to allotransplantation and a combination of intraperitoneal PD-L1.Ig and 1,25-dihydroxyvitamin D₃ ;The blood glucose in the recipients , the pathological changes of the allografts and the survival of pancreatic allografts were observed. And the recipients' peripheral blood,spleens and grafts were harvested from recipient to determine the CD3⁺CD8⁺T cells, CD4⁺ T cells and CD4⁺CD25⁺ T by Flow Cytometry. After transplantation , the level of graft interferon-2,4,10 ,12 in the recipients was determined by ELISA kit analysis also. Results : Compare with Group A, Significantly prolonged allografts survival time was not seen in group B( P > 0. 05);Markedly prolonged recipient survival time and protected allografted function in group C and D, with the longest in group D. The population of CD3⁺CD8⁺T cell and CD4⁺T cell decreaased in groupB ,C and D, though more CD4⁺CD25⁺ T cells were detected, compare to group D, the differences in group D were apparent, as it did when group D compared with A ,B and C (P< 0.01).Concentration of Th1-type cytokine in allograft decreased markedly, Th2 cytokine increased significantly. Conclusion Combined use of PD-L1Ig and 1,25-dihydroxyvitamin D₃ may suppress the cell-mediated immune responses and pancreas allograft rejection effectively and promote further prolongation of the survival of pancreas allografts.