Curcumin inhibits LPS-induced inflammation in rat vascular smooth muscle cells in vitro via ROS-relative TLR4-MAPK/NF-KB pathways

摘要

Aim:To investigate whether curcumin (Cur) suppressed lipopolysaccharide (LPS)-induced inflammation in vascular smooth muscle cells (VSMCs) of rats,and to determine its molecular mechanisms.Methods:Primary rat VSMCs were treated with LPS (1 μg/L) and Cur (5,10,or 30 μmol/L) for 24 h.The levels of MCP-1,TNF-α,and iNOS were measured using ELISA and real-time RT-PCR.NO level was analyzed with the Griess reaction.Western-blotting was used to detect the activation of TLR4,MAPKs,IκBα,NF-κB p65,and the p47phox subunit of NADPH oxidase in the cells.Results:Treatment of VSMCs with LPS dramatically increased expression of inflammatory cytokines MCP-1 and TNF-α,expression of TLR4 and iNOS,and NO production.LPS also significantly increased phosphorylation of IκBα,nuclear translocation of NF-κB (p65) and phosphorylation of MAPKs in VSMCs.Furthermore,LPS significantly increased production of intracellular ROS,and decreased expression of p47phox subunit of NADPH oxidase.Pretreatment with Cur concentration-dependently attenuated all the aberrant changes in LPS-treated VSMCs.The LPS-induced overexpression of MCP-1 and TNF-α,and NO production were attenuated by pretreatment with the ERK inhibitor PD98059,the p38 MAPK inhibitor SB203580,the NF-κB inhibitor PDTC or anti-TLR4 antibody,but not with the JNK inhibitor SP600125.Conclusion:Cur suppresses LPS-induced overexpression of inflammatory mediators in VSMCs in vitro via inhibiting the TLR4-MAPK/NF-κB pathways,partly due to block of NADPH-mediated intracellular ROS production.