AIM:To investigate the effect of microRNA-429 (miR-429) on the expression of occludin (Ocln) in intestinal epithelial cells ( IECs) and intestinal epithelial barrier function in diabetic mice.METHODS:Diabetes mel-litus mouse model was induced by intraperitoneal injection of streptozocin.The expression of miR-429 in IECs of diabetic mice was inhibited by antagomiRNA-429 injected via tail vein.The expression of miR-429 and mRNA expression of Ocln were detected by real-time PCR.The protein expression of Ocln was determined by Western blotting and immunohistochem-istry.The urinary lactulose/mannitol ratio was measured by gas chromatography.The plasma LPS concentrations in the mice were measured by chromogenic end-point TAL kit.RESULTS:The results of real-time PCR confirmed that the ex-pression of miR-429 in IECs of diabetic mice was remarkably inhibited by tail-vein administration of antagomiRNA-429, and resumed to similar level of normal mice on the 6th day after the administration.After suppressing the level of miR-429, the expression of Ocln in IECs of diabetic mice increased significantly (P<0.05), while the urinary lactulose/mannitol ra-tio and the plasma LPS concentration decreased obviously ( P<0.05 ) .CONCLUSION:AntagomiRNA-429 effectively suppresses miR-429 expression in IECs of diabetic mice, and then enhances the expression of Ocln and partially resumes the intestinal epithelial barrier function.

[ ABSTRACT] AIM:To study the process of promoting mouse embryonic stem cells ( ESC) to specify to definitive endoderm by up-regulating of Nodal signal pathway in order to find the best cultivated systems of differentiation of mouse ESC to definitive endoderm cells.METHODS:The cells were divided into different groups based on the culture medium:ESC group ( serum-free medium +LIF) , natural differentiation group ( serum-free medium) and activin A group ( serum-free medium +50μg/L activin A).The cells and the sterilized coverslips with cells were collected at 1, 3, 5 and 7 d of the cultivation.The proportion of CXCR4 +cells was detected by flow cytometry.The expression of CXCR4 was determined by immunocytochemical method, and the protein expression of OCT4 and CXCR4 was detected by Western blot.RE-SULTS:The proportion of CXCR4 +cells showed no dramatic change in ESC group along with the extending of cultivation day, while there were gradually increased in natural differentiation group and activin A group and the highest level was ob-served at 5 d.Among the 3 groups, the proportion of CXCR4 +cells at 5 d was the highest in activin A group.The brown or tan staining in the cells observed under microscope was considered as positive CXCR4 by immunocytochemistry.The pro-tein levels of OCT4 and CXCR4 in ESC group along with the extending of cultivation days was observed.The expression levels of OCT4 were gradually decreased in the cells in natural differentiation group and activin A group, while those of CX-CR4 were gradually increased with the highest level at 5 d.It was highest in the cells in activin A group.CONCLUSION:The proportion of definitive endoderm was the highest at 5 d of the induction during in vitro mouse ESC differentiation.Up-regulation of Nodal signal pathway by adding activin A at the early stage of mouse ESC differentiation promotes mouse ESC to specify to definitive endoderm with CXCR4 molecular marker.