| BackgroundDiabetes associated vascular complications are the major diseases that endanger human health, the complication of stroke, coronary heart disease, renal failure is an important cause of human death and disability. Epidemiological studies show that about50%-80% of patients died of cardiovascular complications. At present, diabetic patients in China has reached 114 million, while adults more about 50% general of prediabetes.Therefore, the prevention and treatment of cardiovascular complications of diabetes is quite grim.Current drug therapy and coronary intervention technology has shown improvement or prevention of diabetes related cardiovascular complications, but the means of intervention and can not effectively reduce our cardiovascular disease morbidity and mortality. Therefore, the urgent need to strengthen the research of pathogenesis, looking for more effective intervention measures.Diabetic vascular lesions involving multiple mechanisms,but the current consensus that elevated levels of oxidative stress induced by high glucose is the key link of diabetic vascular damage. But so far a number of clinical studies confirmed that,exogenous supplementation of Vitamin C and Vitamin E and other antioxidants, the effect is not ideal, and there is an increased risk of heart failure. Therefore, researchers will look to the exploration of endogenous antioxidative stress target. The results showed that multiple endogenous antioxidant stress targets such as rf2, UCP2, AMPK,PKA participate in human disease occurrence and development. But how to regulate these endogenous targets? The related research is less. Previous studies have found that some natural active ingredients such as capsaicin, curcumin may have a critical role in cardiovascular protection by TRPV1, AMPK, UCP2 etc.Cinnamaldehyde is the main active ingredient in the plant cinnamon(Cinnamomum zeylanicum), besides,in the main origin of Indian Folk doctors use cinnamaldehyde for treatment diabetes, and about application of cinnamaldehyde on diabetes.In addition, recent studies have shown that cinnamaldehyde can promote rf2 translocation and upregulation expression of phase II detoxifying enzymes in liver cells, through activation of the rf2 pathway improves metabolic disorder in STZ induced diabetic model, but cinnamaldehyde modulate oxidative stress ability whether related to rf2 still needs further study.ObjectiveIn this study, we will use db/db mice to build the animal model of diabetes, human umbilical vein endothelial cells(Human Umbilical Vein Endothelial Cells, HUVECs)and vascular tissue model induced by high glucose, observation effect of Cinnamaldehyde on vascular endothelial injury in diabetes, for this, we propose the following hypothesis: Cinnamaldehyde can upregulated rf2, promote the translocation of rf2, so that enhance the expression and activity of endogenous antioxidant stress associated molecules such as H¨-1, S¨D and resistance to elevated levels of oxidative stress under the condition of DM, prevent diabetes associated vascular endothelial injury and dysfunction, provide new targets for the prevention and treatment of diabetes associated vascular dysfunction, and provide the experiment basis for intervention of diabetic vascular complications of cinnamaldehyde.Materials and MethodsThis experimental in cell research part using the fluorescent dye Dihydroethidium(DHE) detection of Human Umbilical Vein Endothelial Cells(HUVECs) and the level of superoxide anion; ¨ levels by dye daf-2da fluorescence detection in HUVECs.Mito-S¨X fluorescent probe detection of HUVECs mitochondrial reactive oxygen species level; immunohistochemical detection of HUVECs itrotyrosine level. Animal experiments with glucose meter monitoring fasting blood glucose; H & E staining and fluorescence staining was used to observe the effects of morphology and function of pancreatic; using fluorescent dyes Dihydroethidium(DHE), DAF-2DA observed the intima of aorta and mesenteric resistance arteries on the level of superoxide anion and ¨ levels; using microvascular tension analyzer analysis of the effect of cinnamaldehyde on db/db mouse vascular function and morphology. Mechanism research adopts the rf2 si R A interference and the rf2 inhibitor for Cinnamaldehyde and related pathways research,q RT-PCR observation of cinnamaldehyde intervention on transcription level of rf2 in vascular effects; Western blotting observed effect of cinnamaldehyde on db / db mice aorta rf2, H¨-1, CAT, Q¨1, GPx-1 expression;ELISA kit for detection of mouse plasma H¨-1, CAT, Q¨1, GPx-1 protein levels.Result1 Effect of cinnamaldehyde on damage of HUVECs induced by high glucoseHigh glucose group superoxide anion levels, mitochondrial reactive oxygen species(R¨S) compared with low glucose group increased significantly, ¨ level was significantly lower, and cinnamaldehyde can significantly reduce the high glucose induced HUVECs superoxide anion and mitochondrial reactive oxygen species(R¨S)level, and improve the level of ¨ in HUVECs; cell immunohistochemistry indicated that cinnamaldehyde can significantly reduce the level of itrotyrosine in HUVECs.2 Cinnamaldehyde on glucose metabolism, islet function and related vascular injury12 weeks of cinnamaldehyde intervention was significantly decreased fasting blood glucose level in db/db mice and the weight of db/db mice; cinnamaldehyde can improve insulin sensitivity in db/db mice, improved islet morphology and function, but in db/db mice food intake, blood pressure without significant difference; DHE and DAF-2DA staining indicated that cinnamaldehyde can be significantly reduced superoxide anion levels and improve the level of ¨ in db/db mice mesenteric resistance arteries and thoracic aorta intima; cinnamaldehyde can significantly improve the db/db mouse acetylcholine induced endothelium dependent diastolic function, but for nitroglycerin induced endothelium independent diastolic function can not significant impaction; cinnamaldehyde can improve the db/db mouse aorta intima-media thickness,but no significant difference.3 rf2 pathway effect on vascular injury induced by glucose metabolic disorder of diabetesWestern blotting results indicated that cinnamaldehyde could upregulation rf2 expression in a concentration dependent manner; cinnamaldehyde can significantly against high glucose induced HUVECs superoxide anions and mitochondrial reactive oxygen species(R¨S) level, improve the level of ¨ in HUVECs, rf2 inhibitor and si R A can significantly weaken the role of cinnamaldehyde; long-term cinnamaldehyde intervention significantly up-regulated the express of rf2 and H¨-1, CAT, Q¨1,GPx-1 protein levels in db/db mice aortic tissue.Conclusion1. Cinnamaldehyde can antagonist HUVECs superoxide anion, mitochondrial R¨S production and ¨ levels decreased induced by high glucose, reducing the level of itrotyrosine;2. Cinnamaldehyde can improve the db/db mice of glucose metabolism and insulin sensitivity, improve the morphology and function of pancreatic islets in db/db mice; at the same time, which can improve diabetes associated vascular endothelial dysfunction,but no significant difference on the vascular morphology change.3. Cinnamaldehyde through rf2 signaling pathway play the potential protective effect on diabetic vascular endothelial dysfunction. |
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