Fig. 6

SCF + G-CSF treatment in the chronic phase of severe TBI attenuates TBI-induced microglial pathology in the cortex. a Representative z-projection images show Iba1 immunopositive microglia in bilateral cortex in the chronic phase of TBI. The boxes of a1–a4 in TBI-vehicle controls were enlarged to show the detailed morphology of the microglial dystrophy. The white arrowheads in a1 and a3 show microglial process fragmentation. The yellow arrow in a2 indicates a large swelling (spheroid) at the end of microglial process. The white arrow in a4 shows microglial process beading. b and e Quantification data show that the volume of Iba1⁺ microglia is reduced in all TBI groups (TBI-vehicle, TBI-SCF + G-CSF-single treatment and TBI-SCF + G-CSF-repeated treatment groups) in both the contralateral (b) and ipsilateral (e) cortex. c and f Quantification data show the number of Iba1⁺ microglia in the contralateral (c) and ipsilateral (f) cortex. Note that the TBI-reduced Iba1⁺ microglia are restored by SCF + G-CSF treatment in the contralateral but not in the ipsilateral cortex. Sham: n = 3, TBI-vehicle: n = 4, TBI-SCF + G-CSF-single treatment: n = 5, TBI-SCF + G-CSF-repeated treatment: n = 5. One-way ANOVA followed by Fisher’s LSD test. d Sholl analysis data show morphological complexity of microglia in the contralateral cortex. Sham: n = 36 microglia (in 3 mice), TBI-vehicle: n = 43 microglia (in 4 mice), TBI-SCF + G-CSF-single treatment: n = 43 microglia (in 5 mice), TBI-SCF + G-CSF-repeated treatment: n = 39 microglia (in 5 mice). g Sholl analysis data show morphological complexity of microglia in the ipsilateral cortex. Note that TBI-reduced morphological complexity of microglia in both the contralateral and ipsilateral cortex is ameliorated by SCF + G-CSF treatment. Sham: n = 41 microglia (in 3 mice), TBI-vehicle: n = 40 microglia (in 4 mice), TBI-SCF + G-CSF-single treatment: n = 38 microglia (in 5 mice), TBI-SCF + G-CSF-repeated treatment: n = 40 microglia (in 5 mice). Two-way ANOVA followed by Tukey’s post hoc test for Sholl analysis. Mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001