[Tanshinone IIA attenuates hydrogen peroxide-induced senescence of human umbilical vein endothelial cells through activating SIRT1/eNOS pathway].

Objective To explore the effect of tanshinone IIA (TSA) on hydrogen peroxide (H2O2)-induced senescence of human umbilical vein endothelial cells (HUVECs) and the underlying mechanism. Methods HUVECs were cultured in vitro and divided into the control group, model group and TSA group. The cells in the TSA group were pre-treated with TSA for 24 hours. H2O2 was used to induce cell senescence in the model and TSA groups. Transfection with SIRT1 siRNA was used for the knockdown of SIRT1 in HUVECs. CCK-8 assay was performed to detect cell viability. The expression levels of senescence-related proteins (P21 and P26), SIRT1, phosphorylated endothelial nitric oxide synthase (p-eNOS), and eNOS were detected by Western blot analysis. Senescence-associated β-galactosidase (SA-β-gal) staining was performed to evaluate cell senescence. Results Pretreatment with TSA at low concentrations (10, 20 and 40 μg/mL) for 24 hours did not affect cell viability, while high concentrations (80, 160 and 320 μg/mL) decreased cell viability significantly. In addition, 10, 20 and 40 μg/mL of TSA promoted H2O2-mediated cell viability of HUVECs in a concentration-dependent manner. Compared with the control group, the positive rate of SA-β-gal staining in the model group increased, while the positive rate in the TSA group was significantly lower than that in the model group. The expression levels of P21 and P16 protein in the model group were higher than those in the control group, while SIRT1 and p-eNOS/eNOS were lower than those in the control group. Conversely, the expression of P21 and P16 proteins in the TSA group were lower than those in the model group, and SIRT1 and p-eNOS/eNOS were higher in the TSA group than those in the model group. Transfected with SIRT1 siRNA significantly down-regulated the expression of SIRT1 in HUVECs and the positive rate of SA-β-gal staining was notably raised when SIRT1 was silenced in TSA-treated HUVECs. Conclusion TSA attenuates H2O2-induced endothelial cell senescence by activating SIRT1/eNOS signaling pathway.