Fig. 6: Prior lymphatic defects lead to exacerbated TBI-induced inflammation and cognitive decline.

Mice were subjected to meningeal lymphatic photoablation or a control procedure and then to TBI or a sham procedure 1 week later. a–f Brains were harvested 2 weeks after TBI. a Representative images of the brain hemisphere ipsilateral to the injury and quantification of the percent area of (b) GFAP (red) and (c) Iba1 (gray) immunoreactivity (Sham groups n = 5, TBI groups n = 8). Dashed boxes denote the injury site. d Representative reconstructions of morphology of Iba1+ cells and (e) Sholl analysis. Each data point represents the number of Iba1 + branches intersecting with a radius of 0–50 μm from the soma, calculated by the average of 20 microglia per group (4 Iba1 +  cells per section, 5 mice per group). Number sign (#) indicates that all control groups were significantly different from the Ablated + TBI group from 18–32 μm; ****P < 0.0001, ***P = 0.0003, **P = 0.0034 (calculated at 23 μm). f Quantification of the average number of Iba1+ cells per field of view (Sham groups n = 5, TBI groups n = 8). g The percent performance increase on the accelerating rotarod from day 1 to day 3 post TBI or sham procedure (Not Ablated + Sham n = 20, Not Ablated + TBI n = 32, Ablated + Sham n = 19, Ablated + TBI n = 30; pooled data from four independent experiments). h NLRT experimental schematic and i percent time the mouse spent investigating each object over the total time investigating both objects (Not Ablated + Sham n = 14, Not Ablated + TBI n = 15, Ablated + Sham n = 14, Ablated + TBI n = 16; pooled data from two independent experiments). Each point represents the percent time one mouse spent with either the novel location object (orange) or the familiar location object (blue). All other n values refer to the number of mice used and the error bars depict mean ± s.e.m. P values calculated by two-way ANOVA with Tukey’s multiple comparison correction (b, c, e, f, g) and mixed two-tailed unpaired Student’s t-test with Holm-Sidak multiple comparison correction (i). Source data (b–c, e–g, i) are provided as a Source data file.