ABSTRACT
Objective To observe the influence of warm ischemia time on acquisition of rat pancreatic islets and islet function.Method Male Wistar rats were used.After heart beats stopped,the pancreases in four groups of rats were harvested,and warm ischemia time was 0,15,30 and 45 min separately.The pancrease was preserved in UW at 4℃C for 8 h,and subjected to injection of collagenase solutions.After islets were acquired,the purity,survival rate and islet activity were tested,and statistical analysis was performed.Result The number of islets obtained in 0 min group,15 min group,30 min group and 45 min group was (433 ± 41),(396 ± 38),(350 ± 31) and (66 ± 17)IEQ/one,islet viability was 94％,88％,77％ and 25％,and purity was 88％,78％,60％ and 32％,and insulin release index was 2.38 ± 0.23,2.25 ± 0.18,2.19-± 0.18 and 1.25 ± 0.12,respectively.There was no significant difference in islet number,purity,survival rate and activity 15 min group and 30 min group between 15 min group or 30 min group and 0 min group (P＞0.05).There was significant difference between 45 min group and 0 min group in islet number,purity,survival rate and activity (P＜0.05).The survival rate and purity in 45 min group were lower than the clinical standards for islet transplantation (survival rate ＞ 75％,and purity ＞ 50％).Conclusion Warm ischemia time of 15 min in non-heart-beating brain death(NHBD) rats had no effect on islet isolation and purification.Warm ischemia time within 30 min showed no significant influence on islets of NHBD rats,which can be used in islet transplantation.Warm ischemia time at 45 min showed significant influence on islets of NHBD rats,which can't be used in islet transplantation.
ABSTRACT
BACKGROUND:The use of donor rat of cardiac death inevitably experiences warm ischemia injury, so the length of warm ischemia time plays a significant role on the number and function of pancreatic islet obtained. OBJECTIVE:To investigate the effect of Exendin-4 on pancreatic islet function of donor rats with cardiac death at different heat ischemia time. METHODS:Islet cells from Wistar rats were cultured in vitro and randomly divided into three groups according to the experimental conditions:0, 30, 45 min heat ischemia groups. Each group was further assigned into two subgroups, control group was cultured for 24 hours while experimental group wad cultured with 10 nmol/L Exendin-4 for 24 hours. The number of isolated pancreatic islets was calculated with diphenylthiocarbazone staining, and the purity of the extracted islets was adjusted. The viability of the islets was examined by AO/EB staining, and insulin secretion index assay was used to detect the function of the islets. RESULTS AND CONCLUSION:With the time of heat ischemia increasing, the number, purity, viability and function of islet cells obtained were decreased. After the cells in heat ischemia 0, 30, 45 min groups were cultured with 10 nmol/L Exendin-4 for 24 hours, the number, purity and viability of isolated and purified islets were increased compared to the group without added Exendin-4. There was significant difference between experimental group and control group in 30-minute and 45-minute ischemia groups (P<0.05). Exendin-4 can protect pancreatic islet cells in donor rats with cardiac death at different heat ischemia times, reduce the apoptosis, and improve islet survival and functions. The use of Exendin-4 can be an effective pretreatment method at early ischemia phase of islet transplantation.