Ferulic Acid Inhibits Inflammation Induced By PM_2.5 Through Regulating TLRs Signaling Pathway In Vascular Endothelial Cells

OBJECTIVE To investigate the effect of Toll-like receptors signaling pathway on PM_2.5-induced inflammation in vascular endothelial cells and the intervention of ferulic acid.METHODS 1.Inflammatory factors and toll-like receptors were detected in the aortic tissues of mice after nonsurgical intratracheal instillation of PM_2.5,as well as the human umbilical vein endothelial cells（EA.hy926）treated with PM_2.5.In addition,the secretion of IL-6 and IL-1β,as well as the expression of Toll-like receptors,was determined in the EA.hy926 intervened with TLR2 or TLR4 inhibitors.2.Mice were treated with 10 mg/kg and 20 mg/kg PM_2.5 respectively by onsurgical intratracheal instillation.Additionally,we concurrently treated with 40 mg/kg and 80 mg/kg ferulic acid at the high dose group(20 mg/kg PM_2.5)for 2 weeks.The categories of inflammatory cells and inflammatory factors in serum were detected.Isolated aortic tissue was isolated and the m RNA expression of IL-1β and IL-6 were determined by RT-PCR.The protein level of TLR2,TLR4,My D88 and NF-κB p65 were detected by western-blot.The expression of TLR2 and TLR4 in mice aorta was also evaluated by immunohistochemistry.RESULTS 1.The results showed that PM_2.5 could increase the expression of IL-1β,IL-6,TLR2,and TLR4 in vitro and in vivo.Anti-TLR2 Ig G or TAK242（inhibitors of TLR4）could decrease the levels of IL-1β,IL-6,and the corresponding TLRs.2.PM_2.5 can increase the content of inflammatory cells and the secretion of inflammatory factors in the blood,leading to systemic inflammation.The m RNA levels of IL-1β and IL-6 overexpressed in aortic tissue.Meanwhile,TLRs signaling pathway-related protein was also increased in aortic tissue.After the intervention of ferulic acid,both of the systematic and aortic tissue inflammation was significantly reduced that alleviated the expression of TLR2,TLR4,Myd88 and NF-κB in mice aorta.CONCLUSION 1.We demonstrate that both TLR2 and TLR4 are involved in PM_2.5-induced inflammation responses in the vascular endothelial cells.Inhibition of TLR2 and TLR4 expression has potential to prevent PM_2.5-induced cardiovascular diseases.2.Our study indicated that PM_2.5 can induce the production of aortic inflammation in mice through TLRs signaling pathway.Moreover,ferulic acid can protect mice from PM_2.5-induced aortic inflammation by inhibition TLRs pathway.