| Objective:Diabetes mellitus(DM) is a disease of metabolic dysregulation that results in reduced life expectancy due to disease specific microvascular(retinopathy, nephropathy, neuropathy, impaired wound healing) and macrovascular(heart disease and stroke) complications. In china, Epidemiology of diabetes in 2010 shows that the proportion of people( over 18 years)suffering from diabetes were 9.7%, if Hb A1 c ≥6.5% as a diagnostic criterion for diabetes, the numbers of diabetes were 11.6%. Diabetes is an independent risk factor for cardiovascular disease, the risk of CVD among those with diabetes remains 2-4 fold greater compared with persons without diabetes. Few people with diabetes die of high blood sugar, the majority of people with diabetes die of cardiovascular disease and diabetic nephropathy, so it is impotangt to treatment of chronic complications of diabetes for diabetic patients.Hyperglycemia toxicity involved in the chronic complications of diabetes, but from clinical treatment and the results of several large scale clinical trials indicate that these complications persist and continue to progress unimpeded even when glycemic control is achieved through pharmaceutical intervention.For this reason some people carried a large clinical trial research presented hyperglycemia metabolic memory effect, which is a good explanation of this phenomenon. Early hyperglycemia in diabetic patients can result in damage to the various organs of the body and, even when glycemic control is achieved, the damage persists, then, collectively termed as the “metabolic memory” phenomenon.Several studies have demonstrated that oxidative stress plays an important role in the pathogenesis of cardiovascular alterations observed in diabetic patients and that hyperglycemia is the causal link between diabetes and increased oxidative stress. Previously, four major mechanisms have been demonstrated to mediate hyperglycemia-induced tissue damage: increased flux of glucose through the polyol pathway; increased intracellular formation of AGEs; activation of protein kinase C(PKC) isoforms; and overactivity of the hexosamine pathway. Hyperglycemia induced-ROS overproduction by activating the polyol pathway and hexosamine pathway that is mediated by the binding of AGEs to their receptors(RAGE). In turn, Binding of AGEs to RAGE induces the generation of intracellular ROS and the subsequent activation of the redox sensitive transcription factor NF-k B, which modulates the expression of a variety of genes associated with inflammation and atherosclerosis. Moreover, AGEs that are present in the extracellular matrix decrease elasticity and availability of nitric oxide, reducing endothelium dependent vasodilatation. Chronic hyperglycemia also increases the circulating concentrations of cytokines, growth factors, endothelin-I and angiotensin II, which activate PKC isoforms by binding to their cell surface receptors. PKC activation contributes to hyperglycemia-induced vascular damage inhibiting insulinstimulated endothelial Nitric Oxide Synthase(e NOS) expression in endothelial cells, nitric oxide production in smooth muscle cells, increasing the plasminogen activator inhibitor-I(PAI-I) expression and Nuclear Factor-Kappa B(NF-κ B) activity and promoting the activity of the pro-oxidant enzyme NADPH oxidase.Resveratrol(trans-3,5,4-Trihydroxystilbene) is a naturally occurring polyphenol. Resveratrol, especially abundant in grape skins and red wine, behaves as a reactive oxygen species(ROS) scavenger, metal chelator and enzyme modulator. Some studies show that red wine or resveratrol decrease lipid peroxidation and increase antioxidant enzyme levels in different brain areas of diabetic rats. Recent studies have demonstrated that resveratrol have a protective effect against oxidative stress in different tissues and in pathological conditions such as cardiovascular diseases, inflammatory response, cancer and diabetes.This study was designed by cultured human umbilical vein endothelial cells, to investigate the oxidative damage of high glucose metabolism memory for vascular endothelial cells in vitro, and to explore the effect of resveratrol on metabolic memory model to endothelial cells.Method: Human umbilical vein endothelial cell line(HUVECs)were cultured in vitro. The cultured cells were then divided to normal control group: NG, 5.5mmol/L D-glucose for 3 days; mannitol control group: MA, 5.5mmol/L D-glucose and 24.5mmol/L D-mannitol for 3 days; persistent high glucose group: HG, 30mmol/L D-glucose for 3 days; transient high glucose group: TG, 30mmol/L D-glucose for 1 day then 5.5mmol/L D-glucose for 2 days; transient high glucose+Resveratrol group: TG+0.1-100μmol/L Res, 30mmol/L D-glucose and 0.1-100μmol/L Resveratrol for 1 day then 5.5mmol/L D-glucose for 2 days. We measured cell proliferation(MTT method), SOD level(wst-1 method), MDA level(TBA method) on 1 day, 2 days and 3 days.Result:1 The cells proliferation viability of persistent high glucose group was significantly inhibited compared with normal control group(P<0.01). After replaced normal glucose, the cells proliferation viability of HUVEC partially restored(P<0.05), but still had lower than normal control group(P<0.01). Resveratrol could increase the activation of cells proliferation in a dose-dependent manner in transient high glucose group(P<0.05). The mannitol control group can aslo inhibit the proliferation(P<0.05).2 The level of MDA in mannitol control group higher than normal control group(P<0.05). Compared with normal control group, the level of MDA in persistent high glucose group was significantly increased(P<0.01). The level of MDA transient high glucose group lower than persistent high glucose group(P<0.01), but higher than normal control group(P<0.01). Resveratrol with a dose-dependent manner reduced the level of MDA in transient high glucose group(P<0.05).3 Compared with normal control group, mannitol control group showed a decrease of SOD activity(P<0.05), and the SOD activity of persistent high glucose group, transient high glucose group and resveratrol intervention group were significantly decreased(P<0.01). The SOD activity of persistent high glucose group lower than transient high glucose group(P<0.01). Resveratrol with a dose-dependent manner recovered the level of SOD in transient high glucose group(P<0.05).Conclusion:1 High glucose can inhibit cell proliferation and induce oxidative stress of HUVECs, after replaced normal glucose, the damage persists. This suggests that the metabolic memory effect involved in the mechanism of vascular endothelial injury in diabetic.2 Resveratrol with a dose-dependent manner recovered inhibition of cell proliferation and oxidative stress by the metabolic memory. This suggests that resveratrol on endothelial cells mediated by metabolic memory may have potential protective effects. |
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