Influence of the total saponin fraction from Dioscorea nipponica Makino on TLR2/4-IL1R receptor singnal pathway in rats of gouty arthritis

Dioscorea nipponica Makino have been extensively used in traditional medicine for the treatment of arthritic diseases, particularly gouty arthritis (GA). Sixty male Wistar rats were divided into six groups: the normal group, model group, colchicine group (COL) and three total saponin groups (RDN) (high dose [160 mg/kg], middle dose [80 mg/kg] and low dose [40 mg/kg]). The mRNA and protein expression levels of TLR2, TLR4, IRAK1, TRAF6, TAK1, IKKα, IκBα and NF-κB in the synovial tissue of joint were detected by realtime PCR and WB methods respectively. The contents of IL-1β, IL-6 and TNF-α in the blood serum were measured by Elisa method. The activation of NF-κB was measured by EMSA method. Our study showed that RDN decreased both the mRNA and protein expressions of TLR2, TLR4, IRAK1, TRAF6, TAK1, IKKα, IκBα and NF-κB of the synovial tissue of joint of rats induced with monosodium urate crystal (MSU). They could also reduce the levels of IL-1β, IL-6 and TNF-α in the blood serum. Further, EMSA results showed that RDN reduced the DNA binding ability of NF-κB p65 of model group. RDN has the effect of anti-inflammation in MSU-induced GA model. This is realised by influencing an important inflammatory signal pathway which is called TLR2/4-IL1R receptor signal pathway. It highlights the potential utility of RDN for the management of GA.