[Salidroside attenuates high glucose-induced apoptosis in human umbilical vein endothelial cells via activating the Ca(2)+/CaM/CAMKIIδ/eNOS pathway]

Abstract

Objective: Endothelial oxidative stress plays an important role in the pathogenesis of cardiovascular disease. Salidroside, a phenylpropanoid glycoside isolated from Rhodiola rosea L, could exert potent antioxidant properties. In this study, we investigated the protective effects, and related mechanism of salidroside against high glucose (33 mmol/L)-induced cell damage in human umbilical vein endothelial cells (HUVECs).

Methods: HUVECs were cultured in normal glucose (5.5 mmol/L), high glucose (33 mmol/L), high salidroside (10 µg/ml+33 mmol/L glucose), moderate salidroside (4 µg/ml+33 mmol/L glucose), low salidroside (1 µg/ml+33 mmol/L glucose) and very low salidroside (0.1 µg/ml+33 mmol/L glucose) for 48 h. Cell viability, the level of malondialdehyde (MDA) , reactive oxygen species (ROS) , nitric oxide (NO) , [Ca(2)+]i, calmodulin (CaM) , calmodulin-dependent kinase (CaMK) IIδ, endothelial nitric oxide synthase (eNOS) , active caspase-3 protein expression and eNOS ser 1177 phosphorylation of HUVECs post various treatments were measured. The cell viability was assessed with MTT assay, and the level of ROS, and [Ca(2)+]i was analyzed using flow cytometry. Nitric oxide and MDA was detected by Nitric Oxide Assay Kit and MDA Assay Kit. Western blot was performed to detect the protein expressions of eNOS, active caspase-3 and eNOS ser 1177 phosphorylation.

Results: Comparing to the normal glucose group, high glucose treatment increased the cell damage, the level of NO and [Ca(2)+]i (P < 0.05) , downregulated CAMKIIδ, eNOS expression and eNOS ser 1177 phosphorylation (P < 0.05), elevated the concentration of MDA and ROS (P < 0.05) in HUVECs. Salidroside treatment significantly attenuated high glucose-induce cell damage on cultured HUVECs in a dose-dependent manner. Comparing to the high glucose group, 10 µg/ml Salidroside significantly increased cell viability (P < 0.05) , inhibited high glucose-induced release of MDA , generation of ROS, active caspase 3 protein expression (P < 0.05) , upregulated the release of nitric oxide and [Ca(2)+]i by HUVECs (P < 0.05) , enhanced CaM, CAMKIIδ, eNOS expression and eNOS ser 1177 phosphorylation in HUVECs (P < 0.05) .

Conclusions: These findings suggeste that salidroside could attenuate high glucose induced apoptosis in HUVEC, partly through activating the Ca(2)+/CaM/CAMKIIδ/eNOS pathway.