Total flavonoids from the Carya cathayensis Sarg. leaves inhibit HUVEC senescence through the miR-34a/SIRT1 pathway.

Aging shows a significant relationship with changed vascular structure and function, and advancing age is a major nonmodifiable risk factor in the occurrence of cardiovascular diseases. The senescence of endothelial cells is one of the hallmarks of vascular aging and can induce vascular dysfunction. This study aimed to investigate the effect of total flavonoids (TFs) on human umbilical vein endothelial cells (HUVEC) senescence and identify the potential mechanisms involved. A HUVEC senescence model was induced by angiotensin II. The senescence markers, including senescence-associated ß-galactosidase (SA-ß-gal), p53, p21, and stagnate G0/G1, were measured. The effects of TFs on miR-34/ SIRT1 were examined by quantitative polymerase chain reaction analysis and Western blot analysis. TFs decreased the percentage of SA-ß-gal-positive cells and resulted in G0/G1 cell cycle arrest, while the percentage of cells in the S phase increased. Furthermore, TFs reduced miR-34a expression and increased the expression of SIRT1. After treatment with TFs and a miR-34a inhibitor, the percentage of SA-ß-gal-positive cells and the expression of miR-34a decreased, and the expression of SIRT1 increased. The TFs inhibited HUVEC senescence, and the mechanism was related to the miR-34a/Sirtuin1 pathway.

Involvement of Flavonoids from the Leaves of Carya cathayensis Sarg. in Sirtuin 1 Expression in HUVEC Senescence.

Atherosclerosis is the commonest cause of death in the world and one of the most important processes that occurs with increasing age because it is accompanied by progressive endothelial dysfunction. Recent studies demonstrated that Sirtuin 1 (SIRT1) might potentially affect cell senescence. However, the effect of SIRT1 on the regulation of human umbilical vein endothelial cell (HUVEC) senescence with total flavonoids (TFs) has not been addressed previously. This study investigated how SIRT1 functions in the process of HUVEC senescence when TFs are present and identified the potential molecular mechanisms involved. Using a model of HUVEC senescence induced by angiotensin II, TFs pretreatment reduced the percentage of senescence-associated ß-galactosidase (SA-ß-gal) cells and p53 mRNA expression. The level of SIRT1 protein and E2F1 decreased during HUVEC senescence and could be partially recovered when cells were coincubated with TFs, while the levels of proteins p53 and p21 increased during cell senescence and diminished in response to the TFs treatment. When coincubated with 20 mM nicotinamide, the results with SA-ß-gal-positive cells and the expression of SIRT1, E2F1, p53, and p21 were contrary to that obtained with only TFs pretreatment. The data indicate that the TFs exert their effect on HUVEC senescence through SIRT1.

[Protective Effect of Total Flavonoids from Carya cathayensis Leaf on Cultured H9C2 Cardiomyocytes During Hypoxia / Reoxygenation Injury].

Objective: To study the protective effect of total flavonoids from Carya cathayensis leaf on cultured H9C2 cardimyocytes during hypoxia / reoxygenation( H / R) injury. Methods: Co Cl2 was used to induce the H / R injury model in H9C2 cells at different concentrations,different H / R time. Total flavonoids from Carya cathayensis leaf was added into culture medium with final concentration of2. 5,5 and 10 µg / m L before H / R. Lactate dehydrogenase( LDH), Malondialdehyde( MDA) content, Superoxidedimutase( SOD) activity in the bathing medium were assayed for the evaluation of myocardial cell injury. Myocardial cell viability was detected by the MTS assay kit. Apoptotic changes in H9C2 cells were observed by using Hoechst-PI staining and flow cytometry analysis. The expression of HIF-1αprotein was detected by Western blot. Results: Using 1 200 µmol / L Co Cl2 to hypoxia the cells for 18 h and then reoxygenation for 2 h were the best condition of H / R injury model. Compared with model group,the cells treated with total flavonoids from Carya cathayensis leaf could decrease the activity of LDH and the content of MDA, while increased the activity of SOD. Moreover, they could regulate the expression of HIF-1α protein to normal level. Conclusion: It is suggested that total flavonoids from Carya cathayensis leaf has a protective effect on H9C2 cardiomyocyte during H / R injury. The mechanism may be relate to enhancing the capability of the cell clearing the oxygen free radial, decreasing the production of lipid peroxidation and reducing apoptosis.