Effects of high levels of glucose and insulin on proliferation,apoptosis and cell function of mouse endothelial progenitor cells

Objective To study the effects of high levels of glucose and insulin on proliferation,apoptosis and cell function of endothelial progenitor cells(EPCs) in mice.Methods EPCs were isolated from bone-marrow of mice by density gradient centrifugation method and were divided into four groups:Group A(control group,glucose concentration 5.5 mmol/L),group B(glucose concentration 11.0 mmol/L),group C(glucose concentration 22.0 mmol/L),and group D (glucose concentration 22.0 mmol/L plus insulin 25 U/L).Proliferation of EPCs was determined by MTT assay and apoptosis by flow cytometry.NO and NOS(TNOS、iNOS) in cell culture medium were measured.Results Proliferation ability of EPCs in group B,C and D was similar but significantly decreased compared to group A[group A(1.31±0.21), group B(0.93±0.27),group C(0.78±0.31) and group D(0.57±0.24),all P0.05].After 5 days,apoptosis rates of EPCs in group B,C and D were significantly increased compared to group A[group A(15.75±0.60)%,group B(17.95±0.38)%,groupC(32.5±0.63)%and group D(31.48±1.26)%,all P0.01].Apoptosis rates were higher in group C and D than in group B.Releases of NO and TNOS in group B,C and D were decreased and iNOS increased significantly compared to group A(all P0.01).Conclusions High levels of glucose and insulin can inhibit the proliferation and induce apoptosis of EPCs in mice.Insulin cannot reverse the inhibitory effect of high level of glucose on EPCs in mice.