Fig. 3

SyEV showed anti-inflammatory properties in OMV-treated macrophages and septic mice. a, b The inhibitory dose responses of EV, NV, and SyEV in OMV-activated RAW 264.7 cells. RAW 264.7 cells were pre-treated with OMV (100 ng/mL) for 3 h and then incubated with the same numbers of EV, NV, or SyEV particles for 15 h. The concentration of TNF-α (a) and IL-6 (b) was measured in the conditioned media (n = 3). c THP1-Lucia cells were treated with OMV (100 ng/mL) for 3 h to stimulate NF-ĸB signaling associated with luciferase, and the enzyme activity was measured as RLU (relative light units) following treatment with SyEV (1 × 10⁹) for 18 h (n = 3). d Experimental design for investigating the beneficial effect of NV and SyEV in vivo (n = 5). Mice were i.p. injected with NV or SyEV (2 × 10⁹) at 1 h before administration of a sublethal dose of OMV, and then the mice were again i.p. injected with the same dose of NV or SyEV at 1 h. Six hours after OMV injection, mice were sacrificed to measure inflammatory parameters. e, f The concentration of TNF-α (e) and IL-6 (f) in the peritoneal fluid. g, h The serum level of TNF-α (g) and IL-6 (h). Throughout, the data are presented as the mean ± SEM. ^*P < 0.05, ^**P < 0.01, ^***P < 0.001; ns, not significant, by one-way ANOVA with Tukey’s post test (c-h) or two-way ANOVA with Tukey’s post test versus the OMV-only group (a-b)