Fig. 1

Islet isolation and freeze/thaw procedure. a Schematic illustration of islet isolation from rat pancreas. The method for isolation of rat pancreatic islets consists of three main steps: perfusion, digestion, and purification. A collagenous enzyme is injected into the common bile duct in the perfusion phase. Then, the pancreas is removed from the rat’s body and transferred into a conical tube. The digestion step began when the enzyme solution reached 37 °C to remove islets from the exocrine tissue and was stopped by adding a stop buffer and washing steps to prevent excessive digestion of islets, which could degrade the islet capsules. Finally, the islets were purified using density gradients and multiple washing steps to separate the islets from the non-islet tissue and cultured to maintain cell viability. b Schematic of islet freeze/thaw. The cryopreservation media was added to the isolated islet, cooled to − 20 °C, and then transferred to a liquid nitrogen tank. c Table of thawed process. Cryopreserved mouse, pancreatic islet samples, were removed from liquid nitrogen and transferred to a water bath on dry ice. Rapid thawing in a 37 °C water bath was performed until the last ice crystal was visible in the vial, and dilution of the cryoprotectant with culture medium (RMPI + 10% FBS) was conducted over 24 min as described in the table