Fig 2: Expression of M1 proinflammatory and M2 anti-inflammatory phenotypes in the medial vestibular nuclei (MVN) are modified by the acute LPS treatment after UVN. (A) Confocal visualization of CD11b (M1 phenotype) and IBA1 (microglial cells) stainings in the left MVN of a representative animal in sham, UVN+placebo, and UVN+LPS groups at d3 and d30 post-UVN. Colocalization of both markers is represented by the merged color and examples are indicated by white arrows. (B) Quantification of the number of CD11b-immunoreactive (ir) cells in left MVN at d3 and d30. (C) Quantification of the number of CD11b/IBA1-ir cells in the left MVN at d3 and d30. (D) Confocal visualization of CD206 (M2 phenotype) and IBA1 (microglial cells) stainings in the left MVN of a representative animal in sham, UVN+placebo, and UVN+LPS groups at d3 and d30. Colocalization of both markers is represented by the merged color and examples are indicated by white arrows. (E) Quantification of the number of CD206-ir cells in the left MVN at d3 and d30. (F) Quantification of the number of CD206/IBA1-ir cells in left MVN at d3 and d30. Scale bar, 50 µm. Histograms represents the mean number of ir cells, with error bars representing SEM. * p < 0.05; ** p < 0.01; *** p < 0.001, two-way ANOVA, post hoc Tukey: sham and UVN+placebo comparison is indicated by a blue *; sham and UVN+LPS comparison is indicated by a red *; UVN+placebo and UVN+LPS comparison is indicated by a purple *.

Fig 3: CD11b + expression within the DVC of control and DON-treated animals. A Representative photomicrographs of CD11b and IBA1 labeling taken from coronal brainstem sections of mice treated with vehicle or DON. The white lines symbolize the border between the AP and the NTS. B Overlay photographs of CD11b and IBA1 labeling from coronal brainstem sections of mice treated with vehicle or DON. The white boxes in panels A indicated regions from which panels B originated. Insets illustrate the modification of microglial phenotype in response to DON treatment. Scale bars: 500 µm in A; 50 µm in B. AP: area postrema; cc: central canal; fs: funiculus separans; NTS: nucleus tractus solitarius. C. Quantification of CD11b labeling expressed in mean gray level in DVC subregions of control and DON-treated animals (12.5 mg/kg BW; ***p < 0.001)