Fig. 3

CHIKV-BP infection increases BBB permeability and selectively infect astrocytes in mouse brain. Mice were intraperitoneally injected with 4 μl/g of body weight of a 2% solution of Evans Blue in PBS at 2 d.p.i. and incubated for 3 h. A Quantification of Evans Blue dye incorporated into the brain was performed using spectrophotometry at 610 nm. The values represent mean ± SD (n = 6/group). Statistical analysis was conducted using Kruskal–Wallis test followed by Dunn's multiple comparisons post-test; ***p < 0.001; **p < 0.01; *p < 0.05. Brain slices from CHIKV-infected mice were subjected to double staining for dsRNA (CHIKV), the astrocyte marker GFAP, the microglia marker Iba1, and the neuron marker NeuN. B dsRNA-positive astrocytes were exclusively detected in CHIKV-BP-infected brains. C No dsRNA-positive brain cell were observed in CHIKV-SP-infected brains. Tissue sections were counterstained with DAPI. Single-channel and merged images of the same frames are presented (scale bar: 20 μm). D Comparative analysis of percentage (%) of dsRNA + brain cells