Abstract:

Objective To investigate the influence of fresh and short-term cultured islets on revascularization and function of transplanted islets in mice. Methods Pancreatic islets of donors were obtained from C57 mice by digestion of collagenase P solution and Ficoll 400 density gradient centrifugation. The diabetic C57 mice undergoing syngenetic islet transplantation under renal capsule were randomly divided into three groups, with 10 mice in each group. Mice in group A were transplanted with fresh islets, and those in group B and group C were transplanted with islets with culture of 1 d and 3 d respectively. The changes of blood glucose in diabetic mice after transplantation were observed. The transplanted islets were obtained 14 d after transplantation, HE staining was conducted, immunohistochemical staining of insulin and CD31 was performed, and the microvascular density was calculated. Results The blood glucose of mice was lower than 11.0 mmol/L within 3 d after islet transplantation in three groups. The blood glucose of mice in group A maintained less than 11.0 mmol/L on the 14th day after transplantation, while the blood glucose in group B and group C continued to rise 3 d after transplantation, and was significantly higher than that in group A since then (P<0.05). Immunohistochemical staining of insulin demonstrated that there were a large number of insulin positive cells in cell masses in group A, whereas insulin positive cells were seldomly found in group B and group C. Immunohistochemical staining of CD31 demonstrated a large number of cells positively stained by CD31 under the renal capsule in group A, while there were fewer positive cells in group B and group C. The microvascular density in islets in group A was significantly higher than those in group B and group C (P<0.05). Conclusion Fresh islet transplantation is better than short-term cultured islet transplantation in improving the revascularization and survival of transplanted islets in mice.

Key words: islet transplantation, islet culture, fresh infusion, diabetic mice