P1180 Aims: In the initial days after transplantation hyperglycemia has been related to increasedβcell death and reducedβcell mass, suggesting that transitory hyperglycemia could have a positive effect on transplanted islets. The aim of this study is to identify the insulin treatment that can reduce βcell death after syngeneic islet transplantation. And to test whether insulin treatment to recipient before and after transplantation can save the number of transplanted islet. Methods: Male Lewis rats aged 8-10weeks were used as donors and recipients of transplantation. Islets were isolated by collagenase digestion and histopaque separation method and hand-picked under a dissecting microscope. Islets were cultured for 5days and transplanted into the renal subcapsular space of streptozotocin induced diabetic rats. Three groups of recipient were studied. Group1 (n=6): no insulin treatment; Group2 (n=6): insulin treatment from day 7 before transplantation to transplantation day; Group3(n=6): insulin treatment from day 7 before transplantation to day 7 after transplantation. In each group, 250 islets and 500 islets were transplanted. Blood glucose were measured 28 day after transplantation. Nephrectomy was performed on day 28 and graft was examined in histology (hematoxylin and eosin stain) and immunohistochemistory (insulin stain). Results: In each group, recipient rats transplanted 500 islets maintained normoglycemia throughout the initial 14days. Islet grafts were nice looking and well vascularized. Histologically, these grafts contained abundantβcell. On the other hand, in group3 recipient rats transplanted 250 islets maintained normoglycemia and grafts contained enoughβcell, but failed in that of group1 and group2. Conclusions: Insulin-induced normoglycemia in the initial 7days after islet transplantation could maintain the islets graft in good condition. As a result, we could reduce transplanted islets (250 islets) to maintain normoglycemia.