Effect of Total Saponin of Dioscoreae Collettii Rhizoma on Toll-like Receptor/Nuclear Factor-κB (TLR/NF-κB) Signaling Pathway Induced by Monosodium Urate in THP-1 Cells / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate the effect of total saponin of Dioscoreae Collettii Rhizoma (TSD) on Toll-like receptor/nuclear factor-κB (TLR/NF-κB) signaling pathway induced by monosodium urate in THP-1 cells, in order to explore the possible mechanism of anti-gout arthritis. Method:Phorbol 12-myristate 13-acetate (PMA)-induced THP-1 cells were differentiated into macrophages, divided into normal group, model group, low, medium and high-concentration TSD groups (1, 3, 10 mg·L-1) and colchicine group (0.2 mg·L-1). Except the normal group, the other groups were stimulated with 400 mg·L-1 monosodium urate to replicate an inflammation model in vitro. Cell viability was measured by methyl thiazolyl tetrazolium (MTT) assay, the levels of inflammatory factors tumor necrosis factor-α(TNF-α ) and interleukin-1β(IL-1β) were detected by enzyme-linked immunosorbent assay (ELISA). The protein levels of Toll-like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88) and NF-κB were detected by Western blot. The mRNA levels of TLR4, NF-κB and Pro-IL-1β were measured by real-time fluorescence quantitative PCR (Real-time PCR), and the nuclear shift of NF-κB p65 was detected by immunofluorescence. Result:0~32 mg·L-1 TSD has no effect on cell viability. Compared with the normal group, the secretion levels of inflammatory factors TNF-α and IL-1β in the model group were significantly increased (P<0.01), and the expressions of key proteins (TLR4, MyD88 and NF-κB) and genes (TLR4, NF-κB and Pro-IL-1β) were increased (P<0.01). Compared with the model group, 1-30 mg·L-1 TSD significantly down-regulated the secretion of inflammatory factors TNF-α and IL-1β (P<0.01), the expressions of key proteins (TLR4, MyD88 and NF-κB) and genes (TLR4, NF-κB and Pro-IL-1β) were decreased (P<0.05, P<0.01), and the NF-κB p65 partially trans-located to the cytosol and the superposition in the nucleus were decreased, inhibiting the nuclear translocation of NF-κB p65. Conclusion:TSD may exert an anti-inflammatory effect by down-regulating the expressions of TLR4, NF-κB and Pro-IL-1β mRNA and reducing the secretion of inflammatory factors TNF-α and IL-1β.