Objective:To study the expression of Ngn3 in rats donor islets with different purity

and explore the stem cells in them.Methods:Thirty male adult SD rats were randomly divided into 3 groups.Islets were isolated by digestion method of injecting collagenase into pancreatic duct.Group I was harvested by two digestions without purification;For group Ⅱ(n=10)

islets sediments were purified by adding 25% ficoll-400 and for

Group Ⅲ(n=10)

by adding (25% and 11%)ficoll-400 in order.Finally we applied immunohistochemisiry and RT-PCR to the location and semi-quantitative analysis to test the expression of Ngn3 in the donor islets with different purity.Results:Islets purity of group I was 43.6%±6.29%

Group II 65.3%±4.40%

and group Ⅲ77.6%±6.36%.The difference of Islet purity was significant in three groups (P<0.05).Compared with group Ⅱ and group Ⅲ

the expressions of protein and mRNA of Ngn3 were both highest in group Ⅰ

lowest in group Ⅲ(P<0.05).Conclusion:Ngn3 was expressed in all islets

with the low purity expressing the most prominent

which suggests that islets with low purity may bear more stem cells.