Mechanism of hydroxysafflower yellow A in the regulation of vascular smooth muscle cell calcification

Abstract

Objective To investigate the role and mechanism of Hydroxysafflor yellow A (HSYA) in the calcification of vascular smooth muscle cells (VSMC) induced by β-glycerol phosphate (β-GP). Methods VSMC were cultured with 10% fetal bovine serum+1% double anti-high glucose DMEM medium at 37℃ and 5%CO2 incubator, and were subcultured according to cell growth density at 1∶4 ratio. The cells were divided into three groups: control group (NC), high-phosphate-induced calcification (HP) group, and HSYA intervention (HSYA) group. The Calcium deposition amount was measured by alizarin red staining and calcium determination kit. The expressions of ALP, RUNX2, RANKL, α-SMA and inflammation indicators TLR4, TNF-α, IL-8 were detected by Western blotting method; Western blotting was also used to detect calcification index alkaline phosphatase (ALP) and Runt-related transcription factor 2 (RUNX2). Nuclear factor kappa B receptor activating factor ligand(RANKL), α-smooth muscle actin (α-SMA), and the expressions of TLR4/NF-κB pathway and inflammatory response-related indicators Toll-like receptor 4 (TLR4), interleukin-8 (IL-8) and tumor necrosis factor alpha (TNF-α). The nuclear protein and cytoplasmic proteins were respectively extracted. The expressions of p65 in nucleus and cytoplasm, as well as the expressions of p65 and phosphorylated p65 in total proteins were detected by Western blotting method. Superoxide dismutase (SOD) and malondialdehyde (MDA) kit were used to detect the content of antioxidant enzymes and oxidation end products in cells. Results Western blotting showed that the expressions of ALP, RUNX2 and RANKL in HSYA group were significantly lower than that in HP group. The expression of α-SMA was increased than that of HP group (all P<0.01). The expression levels of TLR4, TNF-α, IL-8 and p-NF-κB/p65 in HSYA group were decreased compared with that in the HP group, and p65 was decreased in nucleus and increased in cytoplasm (all P<0.05). SOD content in HSYA group was significantly higher than that in HP group, and MDA content was significantly lower than that in HP group (all P<0.01). Conclusions HSYA can reduce calcification and calcium deposition of vascular smooth muscle cells induced by high phosphorus. The mechanism is related to the inhibition of the activation of TLR4/NF-κB pathway and the inhibition of oxidative stress. Key words: Hydroxysafflor; Vascular calcification; Nuclear factor-kappa B; Inflammatory; Oxidative stress