Fig. 1
Different spatial patterns of axonal varicosity initiation in rcTBI and CHIMERA. Experiments were performed with Thy1-YFP transgenic mice (2–4 months old, male). YFP fluorescence and Hoechst (a nuclear dye) are shown in green and blue, respectively. A Impact diagram of rcTBI (perfusion and fixation immediately after the 2nd impact). Green arrow indicates the impact direction. Impact site: 3 mm left and 1.8 mm caudal of bregma. B Impact diagram of CHIMERA (perfusion and fixation immediately after one 0.9-J impact). Red arrow indicated the impact direction. Impact site: the bregma. C CHIMERA but not rcTBI or sham induced clear axonal varicosities in corpus callosum (CC) at bregma − 2.06 mm. High magnification confocal images are provided in lower panels. D Extensive formation of axonal varicosities in external capsule (EC) of CHIMERA but not sham or rcTBI. High magnification confocal images are provided in lower panels. E Axonal varicosity induction by both rcTBI and CHIMERA in the cortex. High magnification confocal images are provided on the right for each condition. F Diagram of the spatial pattern of axonal varicosity induction in rcTBI (green asterisks) and CHIMERA (red asterisks). The brain regions above the gray line were the focus of our analysis. Boxed regions were analyzed in C, D and E. G, Summary for the percentage of YFP + axons containing varicosities in CC. Image numbers are provided in the figure. H Summary for the percentage of YFP + axons containing varicosities in in EC. Image numbers are provided in the figure. I Summary for the percentage of YFP + axons containing varicosities in cortical layers I-V. Image numbers are provided in the figure. Mouse numbers: 8 sham, 5 rcTBI and 6 CHIMERA. Unpaired t-test: *, p < 0.05; **, p < 0.001. Scale bars, 250 μm in low mag images and 20 μm in high mag images in C-E