Abstract： Objective To investigate the effect of cold ischemic time on quality and yield of islets isolated from rat pancreas.Methods Wistar rats were divided into 8 group aecording to the cold ischemic time before isolation:0 h group(control group),3 h group,6 h group,9 h group,12 h group,15 h group,18 h group,21 h group.Islets were isolated and purified according to the modified Minnesota program.The quantity and the degree of purity were measured by dithizone staining.The viability was tested by AO/EB staining.Insulin secretion in response to glucose challenge in vitro was determined.Results 560 IE islets were procured from one donor rat averagely in the control group,and the degree of purity was 88%and the viability was 94%.The islet quantity,viability and in vitro function showed no differenee between 3 h or 6 h groups and control group.The quantity and viability were decreased after preservation for more than 9 h.The yield of the islets in 9 h group,12 h group,15 h group and 18 h group were decreased as compared with the control group(P＜0.01,P＜0.05),and there was significant difference among the groups.The yield and function of islets was decreased with prolongation of cold ischemic time.In the 9 h group,1 2 h group and 1 5 h group,the structure of most islets were basically normal,only few islets showed ruptured membrane with endocrine granules leakage.In 18 h group,the purity was 43%and the viability was 36%,which did not meet the clinical criteria.The in vitro function showed the sarne trend.The SI of 18 h and 21 h groups was less than 1.5.The structure of the most islets in these two groups was abnormal.Conclusion The islet vield and function remained perfect after 6 h preservation.Longer cold ischemic time reduced the yield and function,and after preservation for 15 h,the islet graft was not available for transplantation.