Fig. 2
Expression patterns and cellular localization of Mer following TBI. a Representative immunoblots and quantification showing the expression level of Mer protein in the injured cortex at 3 h, 12 h, 1 day, 3 days, and 7 days after TBI or the equivalent area of the sham-operated brains. Data are expressed as fold change compared to sham-operated controls. n = 6 mice per group. b Quantitative RT-PCR was used to assess the mRNA expression level of Mer in the injured cortex at 3 h, 12 h, 1 day, 3 days, and 7 days after TBI or the equivalent area of the sham-operated brains. Data are expressed as fold change compared to sham-operated controls. n = 6 mice per group. Double immunofluorescent staining of Mer with the microglial/macrophage marker Iba-1 in the ipsilateral cerebral cortex was performed at 3 days post-TBI or sham operation. c Fluorescence intensity quantification of Mer expression in activated microglia/macrophages in the impacted cortical area at 3 days after TBI, compared to that in resting microglia/macrophages from sham-operated brains. n = 6 mice per group. d Low-magnification images of the brain (left) indicate the region of interest. Representative confocal images from the ipsilateral cortex (right) showing Mer was abundantly expressed in the plasma membrane of microglia/macrophages and substantially upregulated in activated microglia/macrophages following TBI. The dotted white area indicates contusion region. Scale bar = 15 μm. e Confocal microscopy analysis at a single-cell resolution showing Mer expression was substantially upregulated in the activated microglia/macrophages with phagocytotic morphology at 3 days post-TBI. Orthogonal views demonstrated the colocalization of Mer and Iba-1 in microglia/macrophages. Scale bar = 5 μm. In a, b, data are presented as mean ± SD; *, p < 0.05; **, p < 0.01; ***, p < 0.001; ns, nonsignificant, p > 0.05; versus sham-operated controls; one-way ANOVA followed by Bonferroni’s post hoc tests. In c, data are presented as mean ± SD; ***, p < 0.001 by Student’s t test