Fig. 4

The gut microbiota from ARDS/CAP patients promotes microglia activation and neuroinflammation in the brain of mice. a, b The mRNA expression levels of (a) ZO-1 and (b) occludin in the cortex of mice receiving the faecal microbiota from ARDS/CAP patients (ARDS-R) or normal control subjects (CTRL-R). c, d The mRNA expression levels of (c) ZO-1 and (d) occludin in the hippocampus of ARDS-R and CTRL-R mice. e Typical Iba-1 immunostaining showing the density of activated microglia in the cortex and different hippocampal regions including C1, C3 and DG; Image scale: 200 × magnification. f–i The corresponding quantitative results of Iba-1 positive cells in the (f) cortex and hippocampal (g) C1, (h) C3 and (i) DG regions. j–l The mRNA expression levels of (j) IL-6, (k) TNF-α and (l) IL-1β in the cortex of ARDS-R and CTRL-R mice. m–o The mRNA expression levels of (m) IL-6, (n) TNF-α and (o) IL-1β in the hippocampus of ARDS-R and CTRL-R mice. The statistic difference of various indicators between two groups was evaluated by two-tailed unpaired student’s T test and a statistically significant was defined when p < 0.05. Significant level: *p < 0.05; **p < 0.01; ***p < 0.001