Figure 7.

Lobetyolin inhibits MSU-induced acute gouty arthritis in vivo and in vitro. (A) WT rats were intra-articularly injected with 5 mg/ml MSU to induce gouty arthritis. Rats were additionally treated with lobetyolin (LBT) (10 μM) and PPTN (10 μM) or Veh as respectively indicated (n = 4). (B) The ankle perimeter at 0, 2, 4, 8 12, and 24 h after MSU injection. The representative photograph of ankle at 8 h after the MSU injection. (C) Histologic analyses of synovial membrane. (D) Representative images of synovial tissues infiltrating neutrophils (MPO, red) and presence of NETs (cit-H3, green). (E) Representative images of apoptosis cell (TUNEL, green) in synovial tissues. (F) Primary neutrophils were treated with 250 μg/ml MSU (n = 3). Neutrophils were additionally incubated with LBT (10 μM), PPTN (10 μM), or Veh as respectively indicated. (G) Sytox green assay was used to quantify neutrophil extracellular DNA release in air pouches. (H) Levels of IL-8 and IL-1β in the MSU-treated neutrophil supernatant were measured by ELISA. (I) Representative images of extracellular DNA staining (SYTOX green) in neutrophils. (J) Representative microphotographs of NET formation (cit-H3, green and MPO, red) in neutrophils. (K) Representative images of apoptosis cell (TUNEL, green) in neutrophils. All values are presented as the mean ± SD (^## p < 0.01; ^### p < 0.001 versus corresponding WT+Veh group. ^** p < 0.01; ^*** p < 0.001 versus corresponding GPR105^−/−+MSU group, one-way ANOVA).