Salidroside Attenuates High Phosphate-induced Calcification of Vascular Smooth Muscle Cells Via Inhibiting TLR4/NF-κB Pathway
[Objective]To investigate the effect of salidroside on calcification of vascular smooth muscle cells (VSMCs) and explore its underlying mechanism.[Methods]VSMCs were cultured in high-phosphate media to induce vascular calcification and treated with different concentrations of salidroside. Cell calcification was tested by alizarin red staining and calcium content assay. qRT-PCR and western blotting were used to determine the expression levels of osteogenic proteins including runt-related transcription factor 2 (RUNX2) and bone morphogenetic protein 2 (BMP2),toll-like receptor 4 (TLR4),nuclear factor kappa-B p65 (NF-κB p65),phosphorylated nuclear factor kappa-B p65 (p-NF-κB p65),inflammatory factors including Interleukin-1 beta (IL-1β) and Interleukin-6 (IL-6). We transfected VSMCs with TLR4 small interfering RNA (si-TLR4) and examined whether TLR4 mediated the inhibitory effect of salidroside on calcification of VSMCs.[Results]Alizarin red staining and calcium content assay revealed that different concentrations of salidroside ameliorated high phosphate-induced calcification of human VSMCs (P<0.05). Salidroside at concentrations of 250 and 500 µmol/L decreased the expression levels of RUNX2,BMP2,TLR4,p-NF-κB p65,IL-1β and IL-6 (all P<0.05),but did not affect NF-κB p65 expression (P>0.05). The examination of VSMCs transfected with si-TLR4 showed that salidroside enhanced the inhibitory effect of TLR4 knockdown on calcification of VSMCs (P<0.05).[Conclusions]Salidroside attenuates high phosphate-induced calcification of VSMCs via inhibiting TLR4/NF-κB pathway.