The Protective Effects Of Bone Marrow Mesenchymal Stem Cells On Islet Cells Through VEGF Pathway

Background: Vascular Endothelial Growth Factor(VEGF)is autocrine or paracrine secreted by various cells,and can promote angiogenesis by binding to Vascular Endothelial Growth Factor Receptor(VEGFR).Previous studies have shown that the vasculogenesis of islet cells can be promoted by paracrine VEGF from bone marrow mesenchymal stem cells(BMSCs),thereby increasing islet cells activity.VEGFR contains three kinds of receptors,called VEGFR1,VEGFR2,and VEGFR3.The role of BMSCs in promoting the angiogenesis of pancreatic islet cells remains to be studied.Research purposes: 1.The extraction,culture and purification of mice bone marrow mesenchymal stem cells.2.Mice bone marrow mesenchymal stem cells were co-cultured with mouse islet cells,and to study the effect of mice bone marrow mesenchymal stem cells on islet cells by measuring the insulin secretion.3.To investigate that the bone marrow mesenchymal stem cells promote islet cell proliferation by which type of VEGF receptor pathway.Research methods: 1.Part I :Extraction and purification of mouse bone marrow mesenchymal stem cells.Bone marrow mesenchymal stem cells isolated from bone marrow and were culture-expanded by the cells attached and grew on dishes,and the cells were passaged by trypsin digestion to purify.2.Part ? :Co-culture of mouse islet cells with bone marrow mesenchymal stem cells.The experiments were divided into two group,which includes simple islet culture group,bone marrow mesenchymal stem cells and islet co-cultivation group.Insulin secretion was detected by enzyme-linked immunosorbent assay(ELISA),and the effect of bone marrow mesenchymal stem cells on islet cell secretion was observed.3.Part?: The experiments of vascular endothelial growth factor receptor inhibition.Co-culture of islet cells with bone marrow mesenchymal stem cells,there were four groups to set,the addition of physiological saline group,vascular endothelial growth factor receptor 1(VEGFR1)blockers group,vascular endothelial growth factor receptor 2(VEGFR2)blockers group,vascular endothelial growth factors Receptor 3(VEGFR3)blockers group,and insulin secretion was measured by enzyme-linked immunosorbent assay(ELISA),to find that vascular endothelial growth factor(VEGF)plays the role to promotes vessel formation by which receptor.Research results: 1.The mice bone marrow mesenchymal stem cells adhered to the dishes,and some adherent round cells were seen around 24 h later after inoculation.After about 48 h,the cells grew into,elongated spindle cells.Then 72 h later,most BMSCs can extend pseudopods,gradually exhibit a fusiform or aggregate into a polygonal shape,and the cells gradually fuse together,and then multiply rapidly.After digestion and passage,the purity of cells gradually increased.2.The insulin secretion of the co-culture group was higher than that of the simple culture group,and the difference was statistically significant(P<0.01).(3)The insulin secretion amount of the group with VEGFR1 and VEGFR3 blocker group were lower than the physiological saline group on the 3rd,7th,and 14 th days,but the difference was not statistically significant.The secretion of insulin in the experimental group that added with VEGFR2 blocker decreased compared with that in physiological saline group,and the difference was statistically significant.On 14 th days,the experimental group that added VEGFR2 blocker could not detect insulin secretion.Conclusion: 1.By adherent culture method,bone marrow mesenchymal stem cells can be cultured and purified.2.Bone mesenchymal stem cells have protective effects on islet cells and can promote insulin secretion.3.VEGF secreted by bone marrow mesenchymal stem cells can bind to VEGFR2 which on islet cells,and can exerts protective effects on islets.