The Effect Of Exenatide To Damage And Inflammatory Cytokines Over-expression In NIT-1 Cells Induced By Glucolipotoxicity

Background:Glucose and lipid metabolism disorders associated with the development of diabetes,and long-term high-sugar,high-fat will induce a large number of cytokine production,causing inflammation of islet P cells,resulting in pancreatic β cell damage.But the mechanism of glucolipotoxicity inducedβ-cell dysfunction is not yet clear.Diabetes is an autoimmune and chronic inflammatory diseases,mainly for chronic,low-grade,persistent elevation levels of inflammatory markers.Inflammatory mediator both pathological markers of diabetes,is also the reason the development of diabetes and its complications.Numerous studies show that TNF-a,IL-1β,IL-6 and CRP is a sensitive marker for prediction of diabetes and chronic inflammatory reactions.Toll-like receptors(TLRs)signaling pathway is an important immune and inflammatory response signaling pathway,over-activation of their signals directly induce the autoimmune destruction and loss of tolerance,start or accelerate the process of autoimmune diseases;Therefore,as an important immune and inflammatory signaling pathways,TLR signaling pathway plays an important role in the development of inflammation and immune-related diseases.Numerous studies confirm that GLP-1(Glucagon-like peptide-1)receptor agonist can inhibit atherosclerosis and oxidative stress,improve endothelial function,and have a potential benefits of reducing the risk of cardiovascular event,And atherosclerotic itself is a chronic inflammatory of arterial wall,anti-atherosclerotic effect is largely dependent on the anti-inflammatory effects;These studies suggest that the protective effect of exenatide in islet(3 cells may be related to anti-inflammatory,in addition to lowering blood glucose,may also reduce oxidative stress and inflammation in diabetics.Objective:Observation of the relationship between glucolipotoxicity and TLR3,further understand the possible mechanisms of immune and inflammatory response and damage in islet β cell induced by glucolipotoxicity.Further observation at high glucose and high lipid environment,the relationship between exenatide and TLR3,confirming exenatide has anti-inflammatory effect,whether exenatide can reverse islet β cell injury induced by glucolipotoxicity.Methods:Cultured islet P cell line(NIT-1),give exenatide intervention after the high-fat or high-sugar stimulation.The cell proliferation was observed by CCK-8;TLR3 mRNA expression was detected by real-time quantitative PCR(realtime PCR);The expression of TNF-a,IL-1β,IL-6,CRP,complement C3 and complement C4 in cell culture supernatant were detected by enzyme-linked immunosorbent assay(ELISA);Glucose-stimulated insulin secretion was measured by radioimmunoassay.Results:After high glucose and lipid stimulation,TLR3 mRNA expression was significantly upregulated,TLR3 innate immune and inflammatory signaling pathways are activated,resulting in a large number of immune inflammatory cytokines,TNF-α,IL-1β,IL-6,CRP,complement C3 and complement C4 was significantly increase,the proliferation and insulin secretion of pancreatic β cell was significantly inhibited;and high glucose and high lipid synergistic effect is greater than the individual glycolipid toxicity.Different concentrations of exenatide intervention,TLR3 mRNA was significantly decreased,TNF-a,IL-1β,IL-6,CRP,complement C3 C4 expression and complement decrease,increase islet β cell proliferation rate and insulin levels,exenatide intervention,showing a concentration-dependent manner.Conclusion:High sugar and high fat can significantly increase the expression of TLR3 mRNA in islet β cells,activation of TLR3 innate immune and inflammatory signaling pathways,leading to a large number of immune and inflammatory factors expression,causing the proliferation and insulin secretion of islet β cell was inhibited;and high glucose and high lipid synergistic effect is greater than the individual glycolipid toxicity.TLR3 may play an important role in the process glucolipotoxicity induced islet β cell injury.Under the high glucose and high lipid environment,exenatide significantly reduced expression of TLR3 mRNA,the activation of immune and inflammatory signaling pathway was inhibited,immune and inflammatory cytokines were significantly reduced in a dose-dependent manner;the proliferation and insulin secretionof β cell was increased.Exenatide may inhibit TLR3 immune and inflammatory signaling pathways,resulting in anti-inflammatory effects,against islet P cell injury induced by glucolipotoxicity.