The Improvement Effect Of Ppary Activation On Insulin Resistance Induced By High Glucose In Vascular Endothelial Cells

Objective: To establish a insulin resistance (IR) model induced by high glucosein vascular endothelial cells; to observe the improvement effect of PPARγ activationon IR induced by high glucose in vascular endothelial cells and explore itsmechanism.Methods: Human umbilical vein endothelial cells (HUVECs) were inoculated incells petri dishes and randomly divided into four groups:(1) the control group(Control): DMEM (including Glucose5.5mmol/L) completely cell cultures,(2)insulin resistance group (IR): DMEM (including Glucose33mmol/L) completelycell cultures,(3) Pioglitazone (PG) treatment group (IR+PG): DMEM (includingPG25μ mol/L+Glucose33mmol/L) completely cell cultures,(4) Rosiglitazone(RG) treatment group (IR+RG): DMEM (including RG5μ mol/L+Glucose33mmol/L) completely cell cultures. First HUVECs developed48hours in DMEM(including Glucose33mmol/L) completely cell cultures, Then respectively continueto cultivate24h in contain25μ mol/L PG+33mmol/L Glucose DMEM completelycell cultures (IR+PG) or contain5μ mol/L RG+33mmol/L Glucose DMEMcompletely cell cultures (IR+RG). IR group of HUVECs continue to cultivate24hin the containing DMSO+33mmol/L Glucose DMEM completely cell cultures,Control group of HUVECs cultivate72h in the content of5.5mmol/L GlucoseDMEM completely cell cultures. After the treatment, the cells in the DMEM againwithout serum (including Glucose5.5mmol/L) continue to cultivate4hours, finallyuse insulin (final concentration for5mIU/L) stimulate cell10minutes, collect cells offluid and cells, for the following index test:(1) the cells in the fluid of NO and AngⅡlevel;(2) eNOS protein expression level in HUVECs;(3) PPARγ protein expressionlevel in HUVECs;(4) IKKα/β protein expression level in HUVECs;(5) IκBαprotein expression level in HUVECs;（6）p-IKK α/β(Ser176/181) protein expressionlevel in HUVECs;（7）the cells in the fluid of TNF-α, IL-6, sICAM-1and sVACM-1level. Results:(1) the cells in the fluid of NO and AngⅡ level: HG significantinduced HUVECs insulin resistance, the performance was the lower level of NO andthe higher level of AngⅡ, compared with the Control group with significantdifference (P<0.01); After PG and RG respectively deal with24hours, NO levels riseand Ang Ⅱ level reduced, compared with IR group with significant difference(P<0.05); but IR+PG group compared with IR+RG group with no significantdifference (P>0.05).(2) eNOS protein expression level in HUVECs: eNOS proteinexpression of IR group markedly drop, compared with Control group with significantdifference (P<0.05); eNOS protein expression of IR+PG group and IR+RG groupobviously rise, compared with IR group with significant difference (P<0.01). butIR+PG group compared with IR+RG group with no significant difference (P>0.05).(3)PPARγ protein expression level in HUVECs: PPARγ protein expression of IR groupobviously rise, compared with Control group with significant difference (P<0.01);PPARγ protein expression of IR+PG group and IR+RG group also raised, comparedwith Control group with significant difference (P<0.01), but compared with IR group,no significant difference (P>0.05).(4) IKKα/β protein expression level in HUVECs:IKK α/β protein expression of IR group obviously rise, compared with Control groupwith significant difference (P<0.01); IKKα/β protein expression of IR+PG group andIR+RG group markedly drop, compared with IR group with significant difference(P<0.01), and IR+RG group drop more obvious, compared with IR+PG group withsignificant difference (P<0.01).(5) IκBα protein expression level in HUVECs:compared with Control group, IκBα protein expression level of IR group has noobvious difference (P>0.05), after RG and PG24hours treatment, compared with IRgroup, IκBα protein expression also have no obvious change (P>0.05); after PG andRG48hours treatment, IκBα protein obviously rise, and compared with IR groupwith significant difference (P<0.01), but IR+PG group compared with IR+RG groupwith no significant difference (P>0.05)（.6）p-IKKα/β (Ser176/181) protein expressionlevel in HUVECs: p-IKKα/β (Ser176/181) protein expression of IR group obviouslyrise, compared with Control group with significant difference (P<0.01); after PG andRG24hours treatment, p-IKKα/β (Ser176/181) level scarcely drop, compared with IR group, no significant difference (P>0.05).（7）the cells in the fluid of TNF-α, IL-6,sICAM-1and sVACM-1level: TNF-α, IL-6, sICAM-1and sVACM-1level of IRgroup significantly increased, compared with Control group with significantdifference (P<0.05); after RG and PG24hours treatment, TNF-α, IL-6, sICAM-1and sVACM-1level are significantly reduced, compared with the IR group withsignificant difference (P<0.05), but IR+PG group compared with IR+RG group withno significant difference (P>0.05).Conclusion:(1) PPARγ activation can significantly improve symptom of insulinresistance induced by high glucose in vascular endothelial cells;(2) The mechanismis that PPARγ restrain the IKKα/β/IκBα/NF-κB pathway so as to reduce inflammationformation.