in vitro effects of curcumin on transforming growth factor-β-mediated non-smad signaling pathway, oxidative stress, and pro‐inflammatorycytokines production with human vascular smooth muscle cells

Transforming growth factor-β (tgf-β) induces pro-inflammatory cytokines expression including interleukin-6 (il-6) and tumor necrosis factor-alpha (tnf-α) and these cytokines are associated with the development of atherosclerosis. curcumin has anti-atherogenic effects and anti-inflammatory properties in the vascular wall, but the relative mechanisms are almost unknown. in the present study, we investigate the effect of curcumin on modulating the proinflammatory action of tgf-β in human vascular smooth muscle cells (vsmcs) and its molecular mechanisms. cultured vsmcs were seeded into several groups: a control group (untreated group), a group treated with tgf-β, and several groups treated with tgf-β plus inhibitors. the cells were pretreated with diphenyleneiodonium chloride, dpi, (20 μm), curcumin (5, 10 and 20 μm) and nacetyl- l-cysteine, nac, (10 mm) and then tgf-β (5 ng/ml) was added to the culture medium. the mrna levels of il-6 and tnf-α were detected by quantitative real-time polymerase chain reaction. for monitoring the smad2 linker region phosphorylation (psmad2l), the westernblotting technique was applied and reactive oxygen species (ros) generation was measured by utilizing 2′,7′-dichlorofluorescein diacetate-based assay.