Figure 1.
Growth and colonic lesion in rats.
Body weight change (A). Colon length (B, C). Colon Neurath score (D). Representative images of rat colonic mucosa (E–I), control group (E); colitis group (F); supernatant group (G); F. prausnitzii group (H); B. longum group (I). Upper and lower panel magnifications are ×40 and ×200, respectively. Data are the mean ± SD. n = 7–8. *P <0.05; **P <0.01; ****P <0.001.
Figure 2.
Plasma cytokine concentrations in rats.
IL-10 (A). IL-12 (B). IL-10/IL-12 ratio (C). IL-23 (D). Data are the mean ± SD. n = 7–8. *P <0.05; ***, P <0.003; ****, P <0.001.
Figure 3.
IL-17 protein expression in rat plasma and colon.
Plasma IL-17 concentrations in the rat (A). IL-17 protein immunohistochemical staining in rat colon (B). n = 7–8. Data are the mean ± SD. ****P <0.001. Representative immunohistochemical staining of IL-17 in rat colon mucosa in the control (C), colitis (D), supernatant (E), F. prausnitzii (F), and B. longum (G) groups. Upper and lower panel magnifications are ×40 and ×200, respectively.
Figure 4.
Fecal SCFA concentrations and proportion of total SCFA content in rats.
(A) Fecal acetic acid concentration and percentage as total SCFA content. (B) Fecal propionic acid concentration and percentage of total SCFA content. (C) Fecal isobutyric acid concentration and percentage of total SCFA content. (D) Fecal butyric acid concentration and percentage of total SCFA content. (E) Fecal isovalerate concentration and percentage of total SCFA content. (F) Fecal total SCFA content. Data are the mean ± SD. n = 7–8. *, P <0.05; **, P <0.01; ***P <0.003; ****P <0.001, compared with the colitis group.
Table 1.
Short-chain fatty acids (SCFAs) in fresh cultured and concentrated supernatants.
Figure 5.
IL-10 and IL-12 release from healthy human PBMCs.
IL-10 (A). IL-12 (B). IL-10/IL-12 ratio (C). Data are the mean ± SD; n = 10–14. *, P <0.05; **, P <0.01; ***, P <0.003; ****, P <0.001. Medium, F. prausnitzii cell culture medium. 1× supernatant, one time concentrated supernatant. 2× supernatant, two times concentrated supernatant. 5× supernatant, five times concentrated supernatant. 10× supernatant, ten times concentrated supernatant.
Figure 6.
IL-17 and IL-23 release in vitro.
IL-17 release from rat splenocytes in vitro (A). IL-17 release from co-cultured BMDCs and splenocytes in vitro (B). IL-23 released from the BMDCs with LPS stimulation (C). Data are the mean ± SD; n = 4. *, P <0.05; ****, P <0.001. Cont, control group. PBS, PBS group. Fps, supernatant group. Fp, F. prausnitzii group. Bl, B. longum group. Sbs, sodium butyrate group.
Figure 7.
Proposed working mechanism of the anti-inflammatory effect of F. prausnitzii metabolic products.
The F. prausnitzii metabolic products act via mechanisms on the IL-23/Th17/IL-17 axis. The F. prausnitzii metabolic products inhibit Th17 activity by inhibiting IL-23 secretion from the DCs and reduce the number of Th17 cells by inducing the anti-inflammatory cytokines. → stimulation; -| inhibition.