Effects Of Exendin-4 On Oxidative Stress Levels And Secretion Of PEDF And VEGF In Cultured Human Retinal Pigment Epithelial Cells (HRPE)

Diabetes mellitus(DM)is a metabolic disorder syndrome caused by the interaction of genetic factors and environmental factors.Diabetes,which has became the third leading cause of death.The no.1 and no.2 which cause of death is cancer and cardiovascular disease.At present,the mechanism of diabetic chronic complications of suggests that,four classic pathways leading to complications of diabetes:polyol pathway activation?increase of advanced glycation end products(AGEs)?protein kinase C(PKC)activation?Aminohexose pathway,in essence,it is the result of hyperglycemia-induced peroxidation,and oxidative stress is an important factor in the development of diabetes mellitus.Under the condition of high glucose in the body,and peroxide oxidation system is broken and oxygen free radical absorption ability to drop,tissue and cell damage.Highest vitamin organizations that are rich in polyunsaturated fatty acids intake oxygen in the blood.Therefore,it is more sensitive to oxidative stress.Diabetic diabetic retinopathy(diabetic retinopathy,DR)is the most serious eye complications,high blindness.Multiple pathology involved in the formation of DR.Retinal barrier and the formation of new blood vessels in the retina of basic pathological characteristics of decomposition is DR.Without the development and progress of vascularization in clinic is a challenge.May cause posterior vitreous hemorrhage and retinal detachment,cause vision gradually deteriorated.Vascular endothelial growth factor(VEGF)and pigment epithelium derived factor(PEDF)is considered to be stimulating factor of cardiovascular system and cardiovascular system as the typical representative of inhibiting factor.The balance between the two for the formation of new blood vessels is critical.Studies have shown that high glucose may change the retinal pigment epithelium(RPE)cells secrete the expression of VEGF and PEDF,promote the proliferation of RPE cells.Studies have shown that Glucagon-like peptide-1(GLP-1)and its analogues are resistant to oxidative stress excess responses,improve atherosclerosis,improve endothelial function,The potential benefits of cardiovascular risk,these studies suggest that glucagon-like peptide-1 protects RPE from the role of antioxidant anti-inflammatory effects.Exendin-4(E4)is a native GLP-1 analogue secreted from the saliva of an American lizard,which is 53% homologous to the amino acid sequence of GLP-1 in mammals.At the same time with the promotion of pancreatic insulin secretion,increased insulin sensitivity and improve the role of islet cell function,And is not decomposed by dipeptidyl peptidase IV(DPP-IV),the plasma half-life is longer.Thus in humans,the application of diabetes is stable and long-term treatment of the prospects of the drug.In this study,different concentrations of E4 were applied to human retinal pigment epithelial(HRPE)cell line ARPE-19 for 48 h in high glucose environment,and observe the cell viability,cell morphology,Oxidative stress and its PEDF?VEGF secretion.Then we study the protective effect of E4 to HRPE cells in high glucose,and further explorer the effect and mechanisms of E4 on DR.Methods:The ARPE-19 cell line was cultured in vitro for 48 hours and randomly divided into 5 experimental groups:(1)? normal reference group(glucose concentration: 5 mmol / l);(2)?high glucose group(glucose concentration;(3)?high glucose + E4(12nmol / L)group:high glucose 25mmol/L and E4 12nmol/L;(4)?high glucose + E4(60nmol / L)group:high glucose 25mmol/L and E4 60nmol/L;(5)?high glucose + Ex-4(120nmol / L)group:high glucose 25mmol/L and E4 120nmol/L,Each group of cells was cultured in the cell incubator for 48 hours,which condition is CO2 level(5%)and temperature(37 ° C),and the cells were cultured in the logarithmic growth phase for experiment.Observe HRPE cells vitality and morphology,colorimetry to detect total superoxide dismutase(total-superoxide dismutase,T-SOD),glutathione(glutathione,GSH),and malondialdehyde(MDA),HRPE cells in the supernatant of PEDF and VEGF levels with double antibody sandwich enzyme-linked immunosorbent(ELISA)method to measure,research under the environment of high sugar,E4 protection mechanism of HRPE cells,so as to further study the mechanism of action of the drug for the treatment of DR.1.Under the high glucose environment,the level of oxidative stress of HRPE will be enhanced,and the regulation of vascular excitatory factor and vascular inhibitory factor will be imbalance,resulting in the decline of PEDF secretion and the increase of VEGF secretion.,Which is largely related to the development process of DR.2.In the high glucose environment,certain Concentration of E4 can reduce the oxidative stress of HRPE cells,increase the secretion of PEDF and decrease the secretion of VEGF.This suggests that the E4 possible mechanism of action is that through the regulation of oxidation and antioxidant effects,and then adjust the balance of PEDF and VEGF,so that HRPE cells can be protected,inhibit the formation of DR pathological blood vessels,Prevented the blood-retinal barrier from being destroyed.The two important pathological aspects of DR,that is,the formation of DR pathological blood vessels and blood-retinal barrier function damage has been blocked,which delayed and blocked the DR process.So guess can be applied to prevent DR and treat DR.However,the use of E4 in the clinical prevention of DR development still requires a large number of clinical randomized controlled trials.Conclusion:1.High glucose can enhance the level of oxidative stress,and can lead to increase VEGF secreted by HRPE cells and decrease PEDF the Results: take part in DR.2.A cerain concentration of E4 may inhibi the oxidative stress level of HRPE cells,reduce the secretion of VEGF and increased PEDF secretion.it may play a protective role in HRPE cells injury caused by high glucose,E4 could inhibit the oxidative stress level so that it could inhibit DR pathological neovascularization through regulating the balance between VEGF and PEDF.This has slowed down the course of diabetic retinopathy,so it has the prospects of prevention and treatment of diabetic retinopathy,The use of E4 in the prevention and treatment of diabetic retinopathy also requires a large number of clinical randomized controlled trials to benefit humans.