Experimental Study on Cryopreservation of Pancreas Islet Cell in Rat

Back, Ji Hae; Kim, Song Cheol; Kim, Ik Hee; We, Yoo Me; Kim, Yang Hee; Kim, Jin Hee; Cho, In Hee; Cho, En Young; Lim, Dong Gyun; Han, Duck Jong

Abstract

PURPOSE
Cryopreservation of pancreas islet cells can facilitate the clinical islet transplantation by giving a means of storage of islets and immunomodulation on pancreatic islet preparations.
METHODS
Pancreatic islets were isolated by standard technique using collagenase in rat. Cryopreservation was performed by using DMSO as a cryoprotectant after one day or 48 hr culture. Recovery rate, viability and insulin release in assay in vitro and vivo were checked under the various conditions, such as concentration of DMSO (1.5 M or 2.0 M), culture condition (1 day or 2 day), and taurine treatment.
RESULTS
Percentage of recovery of cryopreserved islet was 56.8+/-10% after thawing. Viability was decreased from 97.2+/-1.1% before cryopreservation to 82.7+/-9.9% after thawing. Glucose stimulation index was reduced from 1.7+/-0.2 before cryopreservation to 1.2+/-0.8 after thawing. Nucleation method by metal rod showed better viability than control (no nucleation) or chamber nucleation method. Mean viability and glucose stimulation index was 81% and 1.5 in one day culture, and 84.2% and 1.2 in 2 day culture before cryopreservtion. Islet treated with taurine showed better insulin release and intracellular insulin content compared with non treated islets before and after cryopreservation. When 4000 IEQ (Islet Equivalent) of islets treated with taurine and non treated cryopreserved islets were transplanted into syngenic streptozotocin induced diabetic rat, all showed normoglycemia over 60 days.
CONCLUSION
Cryopreservation of islets could give a tool of storage with preservation of islet secretion function. However pertinent effort to improve the recovery is needed in order to be used in the clinical islet transplantation.