Objective  To investigate whether pancreatic islet transplantation in combination with bone mesenchymal stem cells (MSC) transplantation can promote the vascularization surrounding the transplant pancreatic islet.

  Methods  The non-obese diabetic (NOD) mice were utilized as the recipients and randomly divided into pancreatic islet transplantation combined with MSC transplantation group (co-transplantation group, n=6), pancreatic islet transplantation group (n=6), MSC transplantation group (n=6) and sham transplantation group (n=3). The variation in blood glucose level and survival rate post-transplantation of NOD mice in each group was observed. The proliferation and apoptosis of the transplant pancreatic islet in the pancreatic islet transplantation group and co-transplantation group at 1, 2 and 4 weeks after pancreatic islet transplantation were analyzed by 5-ethynyl-2'-deoxyuridine (EdU) and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). The vascular density surrounding the transplanted pancreatic islet in the pancreatic islet transplantation group and co-transplantation group at postoperative 2, 4 and 8 weeks were observed under light microscope and quantitatively analyzed by histochemical and immunohistochemical staining.

  Results  Both MSC combined with pancreatic islet transplantation and pancreatic islet transplantation significantly improved the blood glucose level and enhanced the survival rate of NOD mouse models after transplantation. In addition, it could accelerate the regeneration of pancreatic islet cells and decrease cell apoptosis. MSC combined with pancreatic islet transplantation significantly enhanced the vascular density surrounding the transplant pancreatic islet compared with pancreatic islet transplantation alone.

  Conclusions  MSC transplantation can accelerate the vascularization surrounding the transplant pancreatic islet, increase the blood supply and protect the function and activity of the transplant pancreatic islet.