Neoisoastilbin Ameliorates Acute Gouty Arthritis via Suppression of the NF- κ B/NLRP3 Pathway

Abstract

Acute gouty arthritis (AGA) is an acute inflammatory disease, whose occurrence and development mechanism are associated with inflammatory reaction of joint tissue. This study investigated the role of neoisoastilbin (NIA) in the treatment of AGA and explored the underlying mechanisms. C57BL/6 mice underwent intraarticular injection of monosodium urate (MSU) to establish an AGA model in vivo. Enzyme-linked immunosorbent assay, histopathological hematoxylin-eosin staining, western blotting, and other methods were used to observe the therapeutic effects of NIA on AGA and investigate the role of the NF-κB/NLRP3 pathway in the treatment. We found that NIA effectively reduced MSU-induced joint swelling and inflammatory cell infiltration in a concentration-dependent manner. NIA also significantly reduced interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) levels as compared with the respective values in the model mice group. In addition, administration of NIA significantly mitigated the phosphorylation of NF-κB-related proteins (IKKα, NF-κB, and IκBα) and the expression of NLRP3-related proteins (NLRP3, caspase-1, and ASC) in MSU-induced joint tissues. In conclusion, our research indicated that NIA significantly improved AGA, and its underlying mechanism was achieved by simultaneously inhibiting the NF-κB/NLRP3 pathway and the expression of inflammatory factors. This research preliminarily suggested the potential role of NIA in the treatment of AGA.

Figure 1

NIA markedly ameliorated joint swelling in the mouse model of MSU-induced AGA. The changes in joint swelling indices of mice 2, 4, 6, 10, and 24 h after modeling. The results shown are the means ± SD of ten independent experiments; ^#p < 0.05 or ^##p < 0.01 compared with the Con group; ^∗p < 0.05 or ^∗∗p < 0.01 compared with the MSU group.

Figure 2

NIA improved inflammatory cell infiltration in the joint. Hematoxylin-eosin staining of the joints. Each picture shows a representative example of joint tissues from a different group. Magnification: ×20.

Figure 3

NIA inhibited levels of IL-1β, IL-6, and TNF-α in joints. (a) Levels of IL-1β in mice joints. (b) Levels of IL-6 in mice joints. (c) Levels of TNF-α in mice joints. The results shown are the means ± SD of ten independent experiments; ^#p < 0.05 or ^##p < 0.01 compared with the Con group; ^∗p < 0.05 or ^∗∗p < 0.01 compared with the MSU group.

Figure 4

NIA inhibited NLRP3 inflammasome in mice joints. (a) Western blotting analysis of the NLRP3 pathway. The relative protein expression levels of (b) NLRP3, (c) caspase-1, and (d) ASC were normalized to β-actin. The results shown are the means ± SD of three independent experiments; ^#p < 0.05 or ^##p < 0.01 compared with the Con group; ^∗p < 0.05 or ^∗∗p < 0.01 compared with the MSU group.

Figure 5

NIA inhibited the NF-κB pathway in mouse joints. (a) Western blotting analysis of the NF-κB pathway. The relative phosphorylation levels of (b) IKKα, (c) NF-κB, and (d) IκBα were normalized to the corresponding total protein. The results shown are the means ± SD of three independent experiments; ^#p < 0.05 or ^##p < 0.01 compared with the Con group; ^∗p < 0.05 or ^∗∗p < 0.01 compared with the MSU group.

Figure 6

NIA reduced phospho-NF-κB expression in the nucleus and cytoplasm. (a) Western blotting analysis of intranuclear phospho-NF-κB. (b) The relative phosphorylation levels of phospho-NF-κB were normalized to histone H3. (c) Western blotting analysis of intracytoplasmic phospho-NF-κB. (d) The relative phosphorylation levels of phospho-NF-κB were normalized to NF-κB. The results shown are the means ± SD of three independent experiments; ^#p < 0.05 or ^##p < 0.01 compared with the Con group; ^∗p < 0.05 or ^∗∗p < 0.01 compared with the MSU group.