Improved, Low-Cost Methods for Pancreatic Islet Purification in Rats

Abstract

Objective Density gradient separation of islets from exocrine tissue is usually performed using Ficoll. However, this reagent significantly increases the cost of isolation. The aim of the present study was to investigate the effects on islet preparations of purification methods using Lymphoprep and Iodixanol (OptiPrep) density gradients. Methods Pancreata were procured from 46 Wistar rats, loaded with collagenase V (Sigma), and mechanically dissociated using standard procedures. After the digestion phase, the islets purified by 3 methods—Ficoll, Lymphoprep, and Iodixanol (OptiPrep)—were assessed for yields, purity, morphology, and in vitro function. Result We expressed the yields as islet equivalents (IEQ, diameter standardizing to 150 μm), showing no significant differences. Compared with the Ficoll group, the purity was significantly higher in the Lymphoprep ( P = .005) and Iodixanol (OptiPrep) groups ( P = .011). While the viability was >90% in all 3 groups, the viability in the Lymphoprep Group and OptiPrep groups was significantly higher than that of the Ficoll group ( P < .001). In vitro islet function did not differ among the 3 experimental groups. Conclusion Lymphoprep and Iodixanol were as effective as Ficoll in terms of islet yield and in vitro function. High-purity and high-viability islet cells were obtained using improved Lymphoprep-based or Iodixanol (OptiPrep)-based density gradient methods, potential low-cost substitutes for Ficoll.