ABSTRACT
BACKGROUND@#Islet transplantation is currently considered the most promising method for treating insulin-dependent diabetes. The two most-studied artificial islets are alginate-encapsulated b cells or b cell spheroids. As three-dimensional (3D) models, both artificial islets have better insulin secretory functions and transplantation efficiencies than cells in twodimensional (2D) monolayer culture. However, the effects of these two methods have not been compared yet. Therefore, in this study, cells from the mouse islet b cell line Min6 were constructed as scaffold-free spheroids or alginate-encapsulated dispersed cells. @*METHODS@#MIN6 cell spheroids were prepared by using Agarose-base microwell arrays. The insulin secretion level was determined by mouse insulin ELISA kit, and the gene and protein expression status of the MIN6 were performed by Quantitative polymerase chain reaction and immunoblot, respectively. @*RESULTS@#Both 3D cultures effectively promoted the proliferation and glucose-stimulated insulin release (GSIS) of MIN6 cells compared to 2D adherent cells. Furthermore, 1% alginate-encapsulated MIN6 cells demonstrated more significant effects than the spheroids. In general, three pancreatic genes were expressed at higher levels in response to the 3D culture than to the 2D culture, and pancreatic/duodenal homeobox-1 (PDX1) expression was higher in the cells encapsulated in 1% alginate than that in the spheroids. A western blot analysis showed that 1% alginate-encapsulated MIN6 cells activated the phosphoinositide 3-kinase (PI3K)/serine/threonine protein kinase (AKT)/forkhead transcription factor FKHR (FoxO1) pathway more than the spheroids, 0.5% alginate-, or 2% alginate-encapsulated cells did. The 3D MIN6 culture, therefore, showed improved effects compared to the 2D culture, and the 1% alginate-encapsulated MIN6 cells exhibited better effects than the spheroids. The upregulation of PDX1 expression through the activation of the PI3K/AKT/FoxO1 pathway may mediate the improved cell proliferation and GSIS in 1% alginate-encapsulated MIN6 cells. @*CONCLUSION@#This study may contribute to the construction of in vitro culture systems for pancreatic islets to meet clinical requirements.
ABSTRACT
Objective To study of effects Medlar flavone on NO and NOS in H 2 O2 damaged vascular endothelial cells.Meth-ods Human Umbilical Vein Endothelial Cells(HUVEC)have been set as research object.HUVEC cells was damaged by H 2 O2 in-duced oxidative stress.Experiments were divided into normal control group,H 2 O2 injury group,VitC control group,and low,medi-um,high flavonoids protective groups(100,200,400 mg/L).MTT method was used to observe cells activity.The effects Medlar fla-vone on MDA、TNOS、iNOS and NO in H 2 O2 damaged vascular endothelial cells was observed.Results (1)MTT result demonstra-ted the IR of HUVEC cells was 38.8% in H 2 O2 injury group.Which in low,medium,high flavonoids protective groups were 34.0%,30.7%,25.5%.All were lower than H 2 O2 injury group(P <0.01).(2)Compared with normal control group,NOS activity was decreased in H 2 O2 injury cell,while TNOS,iNOS,NO was more.Compared H 2 O2 group,the change of NO,TNOS,iNOS, MDA was opposite in flavone intervention group,and which were dose dependent (P <0.01 ).Conclusion Medlar flavone has a protective effect on H 2 O2 induced HUVEC cells injury,and there may be some kind of relevance between them.