Isolation and purification of islets in non-obese diabetic mice

Objective To investigate the method of isolating and purifying islets in non obese diabetic(NOD) mice. Methods The isolation of adult NOD mice pancreatic islets was carried out by stationary digestion after pancreatic ductal injection of collagenase solution. A discontinuous Ficoll solution(25%,23%,20.5%,11%) was applied to the purification of the islets. The specificity of the islets was determined by dithizone(DTZ) staining, and the function was evaluated by the glucose stimulating insulin releasing test. Results The yield and activity of the islets varied with different concentration collagenase and digesting times. After incubation of the pancreas with 1.0 mg·ml -1 Type Ⅺ collagenase for 40 min, each pancreas could yield (195±8) islets, with viability90% and purity90%. The islets were red and intact after DTZ staining. The insulin from the islets fed with high concentration glucose was 2 times that with low concentration. Conclusion The modified method of pancreatic ductal collagenase injection, followed by stationary digestion and purification of islets with a discontinuous Ficoll solution, can reproducibly yield various and pure islets.