Effect of the semen extract of Cuscuta chinensis on inflammatory responses in LPS-stimulated BV-2 microglia

AIM: To investigate the anti-inflammatory activities of the semen extract of Cuscuta chinensis Lam.(Cuscutae Semen; CS) on the production of inflammatory mediators, nitric oxide(NO), prostaglandin 2(PGE2), and proinflammatory cytokines in lipopolysaccharide(LPS)-stimulated BV-2 microglia. METHOD: BV-2 cells were treated with CS extract for 30 min, and then stimulated with LPS or without for 24 h. The levels of NO, PGE2 and proinflammatory cytokines were measured by Griess assay and ELISA. The expression of inducible nitric oxide synthase(iNOS), and cyclooxygenase(COX)-2 mRNA and protein was determined by RT-PCR and Western blot, respectively. The phosphorylation of extracellular signal-regulated kinase 1/2(ERK1/2), Jun N-terminal kinase(JNK), and p38 mitogen-activated protein kinase(MAPK), and the nuclear expression of nuclear factor(NF)-κB p65 were investigated by Western blot analysis. RESULTS: CS extract significantly decreased the production of NO and PGE2 by suppressing the expression of iNOS and COX-2 in activated microglia. CS extract decreased the production of TNF-α, IL-1β, and IL-6 by down-regulating their transcription levels. In addition, CS extract suppressed the phosphorylation of ERK1/2, JNK, and p38 MAPK, and the nuclear translocation of NF-κB p65 in activated microglia. CONCLUSION: These results indicate that CS extract is capable of suppressing the inflammatory response by microglia activation, suggesting that CS extract has potential in the treatment of brain inflammation.