Fig. 4
Microglia morphology changes 7 days after TBI and antibiotic induced gut microbial dysbiosis. a Experimental design. b Gating strategy of Ly6Chigh in the hippocampus. c–f Quantification of absolute cell numbers in the brain. Mean values are plotted ± SEM, two-way ANOVA followed by Tukey's multiple comparisons. F statistic for antibiotic*injury presented unless otherwise noted (*p < 0.05, **p < 0.01 ***p < 0.001, ****p < 0.0001). c microglia (CD45lowCD11b+), n = 6–8 per group, Finjury (1,23) = 7.45, p = 0.012. MFI of d TLR4, hippocampus Finjury (1,13) = 6.575, p = 0.024, Fantibiotic (1,13) = 9.9, p = 0.008, and cortex Fantibiotic (1,13) = 14.58, p = 0.0021; e MHCII, hippocampus Fantibiotic (1,13) = 6.32, p = 0.026, cortex Finjury (1,13) = 14.93, p = 0.002, Fantibiotic (1,13) = 9.48, p = 0.009, on microglia (CD45lowCD11b+) gated populations. f monocytes (CD45highCD11b+Ly6C+), F(1,24) = 6.24, p = 0.02. g Quantitative measurement of Il-1α, Il-1β, Il-2, Il-10, Il-17, Tnf-α, Ifn-γ and Ccxl13 transcripts, unpaired t test, *p < 0.05. h Representative images of Iba1 + cells in the CA3 region of ipsilateral hippocampi (indicated by the dotted line) and i stereological quantification, Finjury (1,22) = 74.8, p < 0.0001, Fantibiotic (1,22) = 5.94 p = 0.023. Scale bars are 100 µm. j Representative three-dimensional reconstruction images of microglia cells. Scale bars are 15 um. k–o Quantification of microglia morphology. k Dendrite length, Finjury (1,20) = 124.3, p < 0.0001, Fantibiotic (1,20) = 30.9, p < 0.0001; l number of segments, Finjury (1,20) = 94.3, p < 0.0001, Fantibiotic (1,20) = 21.7, p < 0.0002; m number of branch points, Finjury (1,20) = 104.4, p < 0.0001, Fantibiotic (1,20) = 24.4, p < 0.0001; n number of terminal points, Finjury (1,20) = 88.0, p < 0.0001, Fantibiotic (1,20) = 18.78 p < 0.0004; and o volume, Fantibiotic (1,20) = 22.63 p < 0.0002. Abbreviations: VNAM, vancomycin, neomycin-sulfate, ampicillin and metronidazole; CCI, controlled cortical impact; MFI, median fluorescence intensity; TLR4, toll-like receptor 4; MHCII, major histocompatibility complex II