OBJECTIVE: To establish a method for isolating and purifying islets of non-obese diabetic (NOD) mice, and to study their biological properties in vitro and in vivo.
Methods: The modified collagenase digestion combined with Ficoll density gradient centrifugation was used to isolate and purify the pancreatic islets of NOD mice. The function of isolated and purified islets was detected by in vitro glucose stimulation test, and the in vivo biological function of transplanted islets was analyzed by monitoring blood glucose, body weight changes and glucose tolerance test of transplanted mice, and the subrenal capsule was detected by HE staining and immunofluorescence staining. Survival of transplanted islets.
RESULTS: The yield of islets was (116±12) islets/pancreas, and the purity was more than 90%. The results of in vitro glucose stimulation experiments showed that the glucose-stimulated insulin release level of islets of NOD mice was significantly lower than that of islets of KM mice. Pancreatic islet transplantation experiments show that transplanted islets can effectively improve blood sugar, body weight and glucose tolerance in diabetic mice, but the improvement is generally only maintained for about 2 weeks. The results of HE staining and immunofluorescence staining showed that insulin-positive islet cell clusters were found under the renal capsule, and a large number of lymphocytes infiltrated around the remaining transplanted islet cell clusters.
Conclusion: A large number of high-purity islets can be isolated from NOD mice through the improved mouse islet isolation method, which can be used for future research on how to block autoimmune damage and protect transplanted islets.