The Expression Of AAT And Nephrin In The Endothelial Cells Of Transplanted Islets

Objective To study the expression of AAT(α1-Antitrypsin) and Nephrin in the endothelial cells of transplanted islets.Methods Islets of pancreas were isolated by pancreatic ductal injection of collagenase, and islets were purified by discontinuous gravity gradient of Ficoll-400. The purified islets were transplanted into the liver of diabetes SD rats immediately through portal vein. The immunosuppressive tacrolimus(FK506 0.1mg.kg-1.d-1 ) and mycophenolate mofetil(MMF 40mg.kg - 1.d - 1) were administrated to the recipients by intragastric administration after operation. To evaluate the function of transplanted islets,blood glucose levels were determined three times a week by using a glucometer. The recipients were divided into four groups (A,B,C,D) randomly. The recipients of four groups were separately killed in7d,14d,40d and 60d after transplantation. The levels of protein of AAT and Nephrin positive cells were detected by immunohistochemistry.Results1. By digestion with collagenas, the islets yield was 662.33±148.05 islets per pancreas, the purity was 85% and the survival rate was beyond 92%.2. Severe rejection has not been observed in the recipients, and blood glucose levels became normal in 3 to 5 days after operation. There were many morphologically intact islets located the branch of portal vein after transplantation.3..The protein of AAT was expressed in IECs of each group.The side density value positive reaction was investigated by immunohistochemistry,endogenous islets:0.0673±0.0132, groupA:0.0627±0.0107, groupB: 0.0542±0.0113,group C: 0.0479±0.0095, group D: 0.0364±0.0087. There was significant difference among each group (P﹤0.05).4. The protein of Nephrin was expressed in IECs of each group. The side density value positive reaction was investigated by immunohistochemistry , endogenous islets:0.0593±0.0124, group A: 0.0541±0.0093 , group B: 0.0497±0.0072 , group C: 0.0396±0.0081, group D:0.0368±0.0053. Significant difference was also observed in various group (P﹤0.05).Conclusion1. High-quality islets could be obtained by pancreatic ductal injection of collagenase and discontinuous gravity gradient purification.2. FK506+MMF could provide effective immunosuppression, and prolongs islets allograft survival in the environment of liver. 3. The endothelial cells of donor islets participated in the revascularization after islets transplantation.4. The expression of AAT and Nephrin in transplanted islet endothelial cells was decreased gradually with the time. The low concentration of AAT and nephrin can might have an effect on revascularization and the function of endocrine secretion in the graft.