The Influence Of Quercetin On The Activity And Expressions Of MMP-9and MMP-2in Human Umbilical Vein Endothelial Cells With High Glucose

Objective:Diabetes mellitus (DM) is one of the most common chronicdiseases in clinical.With the development of economy, the people,s life hasimproved and the incidence of diabetes has been increasing year by year.Complications Caused by diabetes such as heart, brain, kidney and retinalblood vessels seriously affect the quality of people’s lives.The morbidity andmortality of diabetes are also after the cancer and the cardiovasculardisease.Type2diabetes(T2DM) mainly affects the whole body blood vessels,such as the aorta, the carotid artery and lower extremity artery.The mainpathological change of is atherosclerosis, including endothelial cell injury、vascular matrix decomposition and the membrane gradual degeneration in thearteries.The secondary lesions are the bleeding within the plaques, the burstingof the fibrous cap, and the formation of local thrombosis.Under the normalcircumstances, vascular matrix is in dynamic equilibrium of synthesis anddecomposition, so it maintains the normal vessel function and permeability. Inpathological conditions, this balance is broken and disorder the vascularmatrix metabolism which cause the endometrium damaged, so that the visiblecomponent is into the membrane. Through a series of pathological changes,the atheromatous plaque is formed.The Mechanism of high glucose whichleads to AS is varied, which mainly includes: the glycosylation end-products(AGEs) formation, the promotion of the insulin resistance (IR) and themetabolic abnormalities of polyols. High glucose by stimulating a variety ofcytokines and ingredients such as NO, TNF-α, VEGF, ET-1directly orindirectly activates the pathways which cause the changes of the above.Metal matrix protease (MMPs),a big enzyme system, is one of the mainenzymes involved in substrate metabolism.MMP-2and MMP-9are gelatinases,also called type IV collagenase, mainly break down type IV and Vcollagen and gelatin ingredients.The main components of the vascular matrixis the type IV collagen, so the gelatin enzyme plays an important role.The resistance to atherosclerosis has significant meaning to the quality oflife for patients with diabetes. Diabetes complications have a poor treatmenteffect. The current development of the natural process of western medicinehas a delay effect, but also has some limitations on treatment.The Chinesemedicine has a lot of adverse effects with multi-level and multipletargets.Therefore, the Chinese medicine causes more and more attention fromscholars. According to researches, that flavonoids have resistance toatherosclerosis, antihypertension, anti oxidative stress, inhibiting aldosereductase, restraining the enzyme glycosylation and other pharmacologicaleffects. Quercetin (Qu) is one of the strongest material in antioxidation. Thedata shows: Qu can effectively play the role of resistance to atherosclerosis,but the mechanism is not yet clear.This experiment uses differentconcentration of Qu in the condition of high glucose of Human UmbilicalVein Endothelial (HUVECs) by48hours.We observate the proliferation andthe expression of MMP-2and MMP-9. We can comprehend the role ofprotection mechanism in the Qu.It lays a foundation for the treatment ofdiabetic complications.Methods: The HUVEC cells were cultured and randomly divided intodifferent groups: normal control group (glucose5.5mmol/L), high glucose gr-oup (glucose30mmol/L), mannitol control group (5.5mmol/L low glucoseand24.5mmol/L mannitol), the normal glucose+Qu groups:(12.5μmol/L、25μmol/L、50μmol/L、100μmol/L）group, the high glucose+Qu groups:（12.5μmol/L、25μmol/L、50μmol/L、100μmol/L）group. They werecultured in different conditioned medium for12h、24h、48h, the logarithmicphase cells were used in the experiment. The HUVEC cells number, form andactivity are observed by MTT assay. The expressions of MMP-2and MMP-9are measured by Western Blot and enzyme linked immunosorbent assay(ELISA). Results:1MTT showed that:Between each group,compared with normal controlgroup,the activity in high glucose group was obviously lower,and theinhibition enhanced with the increase of time (P<0.05). There was nosignificantly difference between mannitol control group and normal controlgroup(P>0.05). The activity in the normal glucose and Qu（12.5μmol/L、25μmol/L、50μmol/L、100μmol/L）group had no significantly difference in thenormal control group.It Basically excepted the toxic effects of drug itself tocells. There was no significantly difference between the high glucosegroup+Qu（12.5μmol/L）group and the high glucose group in12hours(P>0.05), but as time prolonged, the cell activity was higher thanhigh glucosegroup（P＜0.05）.The activity in the high glucose and Qu（25μmol/L、50μmol/L、100μmol/L）group was increased than the high glucose group, but itwas lower than normal control group(P<0.05).It was time-dependence anddose-dependence (P<0.05).2Western blot results showed that compared with the normal group, theexpressions of MMP-2and MMP-9intracellular in the high glucose groupwere increased (P<0.05),and the dose of MMP-2was higher thanMMP-9.They were reduced of Qu（25μmol/L、50μmol/L、100μmol/L）group (P<0.05), but they were still higher than normal control group. Ingeneral, they were dose-dependent.3ELISA results showed that compared with normal group, theexpressions of MMP-2and MMP-9extracellular in the high glucose groupwere increased (P<0.05).They were reduced of Qu（25μmol/L、50μmol/L、100μmol/L） group (P<0.05), but they were still higher than normal controlgroup. In general, they were dose dependent.Conclusion:1High glucose can inhibit the activity of HUVECs and affect thevascular endothelial cells; At the same time it can make the expressions ofMMP-2and MMP-9increase.They affected the integrity of the vascularintima.This may be related to diabetic angiopathies. 2A certain concentration of Qu,to some extence, can improve the cellviability of HUVECs in the high glucose and inhibite the expressions of MMP-2and MMP-9. Qu maybe play a significant role in protecting the vascularendothelial cells and the normal metabolism of vascular matrix.Thisexperiment provided a certain theoretical basis for the clinical application ofQu.