Figure 1.

Gut microbes protect against CLP-induced mortality and organ damage. (A) Survival curve after moderate cecal ligation and puncture (CLP) or sham surgery. Mice received a daily oral gavage PBS or ABX cocktail (ABX) for three days followed by moderate CLP or sham surgery (Sham, n = 4/group; CLP, n = 12/group). (B) Representative lung H&E images and histological scores of lung tissues. Mice were pretreated with PBS or ABX for 3 days and then performed moderate CLP or sham surgery. Tissue samples were collected at 16 h after surgery (Sham, n = 3/group; CLP, n = 6/group). Insets are low magnification images, Scale bar = 1 mm; high magnification view (200 × ), Scale bar = 100 μm. (C) Plasma ALT, AST, and Cr levels at 16 h after moderate CLP or sham surgery (sham, n = 4/group; CLP, n = 6). Experimental design as in Fig. 1B. (D) KEGG enrichment analysis of differentially expressed genes between CLP + ABX and CLP groups in the peritoneal lavage fluid (PLF) cells. Red color shows characteristic inflammatory pathways. Mice were pretreated with ABX for three days followed by moderate CLP surgery and 16 h later PLF cells were collected for Bulk RNA sequencing (n = 3/group). (E) Significant up-regulation of genes involved in MAPK signaling pathway, cytokine–cytokine receptor interactions and chemokine signaling pathway in ABX pretreated septic mice (n = 3/group). Experimental design as in Fig. 1D. (F) Plasma TNF-α, IL-1β and IL-6 protein levels in mice at 16 h after moderate CLP or sham surgery (Sham, n = 4/group; CLP, n = 6/group). Experimental design as in Fig. 1B. (G) Schematic diagram depicting fecal material (cecal content) injection protocol. Mice were injected intraperitoneally (i.p.) with a single dose of fecal material (FM, cecal content) supernatant (100 μL) and tissue samples were collected for subsequent experiments. (H) Survival curve of control (FM) and ABX-pretreated mice (ABX + FM) after fecal material (cecal content) supernatant injection (n = 18/group). Experimental design as in Fig. 1G. (I) Representative H&E images and histological scores of lung tissues at 16 h after fecal material (cecal content) supernatant injection. Insets are low magnification images, Scale bar = 1 mm; high magnification view (200 × ), Scale bar = 100 μm. n = 7/group. Experimental design as in Fig. 1G. (J) Plasma ALT, AST, and Cr level in fecal materials injected mice (n = 7/group). Experimental design as in Fig. 1G. Data are expressed as mean ± SEM. The survival curves were analyzed by the log-rank test. P values were determined by a two-tailed unpaired Student's t-test for two groups, one-way analysis of variance (ANOVA) analysis was used for three or more groups. ∗P < 0.05 was considered statistically significant. n: indicates number of samples.