Objective To investigate the revascular and transplanted effects of islet grafts after co-transplantation with vascular endothelial cells ( ECs) in diabetic rats. Methods The rat ECs and islet cells were isolated and purified, then subcutaneously co-transplanted to the inbred SD male rats with diabetes mellitus, the group of islets transplanted alone, group of phosphate buffered solution, and group of normal rats served as control. Islet grafts revascularization degree, islet cells activity and apoptosis were observed by immunohistochemical double staining of CD31, insulin and factor associated suicide (Fas) antibody. The results of intraperitoneal glucose tolerance test (IPGTT) and intraperitoneal insulin tolerance test (IPITT), the blood glucose and insulin levels of the rats and the survival time of the islet grafts were compared. Results The blood glucose concentrations of IPGTT and IPITT, the blood glucose and insulin levels of rats analyzed by multivariate analysis in the ECs and islets transplantation group were better than those in the islets transplantation alone group (P<0.05). The islet grafts mean survival time of the ECs and islets transplantation group was longer than that of the islets transplantation alone group (P<0.05). On the 7th day after transplantation, mean microvascular density of islet grafts per square millimeter in the ECs and islets transplantation group was 26.4 ± 6.1, significantly greater than that in the islets transplantation alone group 18.3 ± 5.7 (P<0.05). In the ECs and islets transplantation group, insulin staining intensity was higher than that in the islets transplantation alone group (P<0.05), while factor associated suicide(Fas) staining intensity was lower than that in the islets transplantation alone group ( P<0. 05 ). Conclusion Co-transplantation with ECs could promote the revascularization of islet grafts and improve the effect of islet transplantation.

Objective To investigate the influence of VEGF165 gene transfection on the revascularization and transplantation effect of islet grafts.Methods The rat islet cells were transfected with lentivirus containing VEGF165 gene (LV-VEGF165) in vitro,then transplanted to the renal capsule of inbred SD male rats with diabetes mellitus.Islet cells transfected with lentivirus marked with AcGFP1 and no VEGF165 gene were set as null vector control group (LV-AcGFP1 group),individual islet cells as blank control group.VEGF165 expression in vivo and in vitro was detected by ELISA.The islet grafts revascularization degree and islet cell activity were observed by immunohistochemical double staining of insulin and CD31 antibody.Blood glucose and insulin level of rats with diabetes mellitus and survival time of islet grafts were compared.Results The VEGF165 concentrations in the LV-VEGF165 group secreted by islet cells in vivo and in vitro were significantly higher than those in the LV-AcGFP1 group and the blank control group (P＜0.01).Mean microvascular density (MVD) of islet grafts per square millimeter in the LV-VEGF165 group was (24.3 ± 3.7),significantly greater than that in the LV-AcGFP1 group (12.4 ± 2.5) and the blank control group (12.4 ± 2.5) (P＜ 0.01).Insulin staining intensity in the LV-VEGF165 group was also higher than that in the LVAcGFP1 group and the blank control group.The blood glucose and insulin levels in rats with diabetes mellitus analyzed by multivariate analysis in the LV-VEGF165 group were controlled more effectively than those in the LV-AcGFP1 group and the blank control group (P＜0.01).The islet grafts mean survival time (MST) after transplantation in the LV-VEGF165 group was longer than that of the LVAcGFP1 group and the blank control group (P＜0).01).Conclusion The VEGF165 gene transfection to islet cells could promote the revascularization of islet grafts and improve the effect of islet transplantation.