Supplementary Fig. A2.

Recruitment of neutrophils to brain parenchyma after intracerebral injection of 100 ng IL-1β during postnatal period. Neutrophil distribution in the brain, shown by representative spatial maps and immunohistochemistry of neutrophils (brown; anti-neutrophil serum) and vessels (pink; laminin), was limited at 4 h following intracerebral injection of 100 ng IL-1β into the striatum at P7, P14, P21 and P56. The number of neutrophils per mm² of striatum either in the parenchyma or in vessels was significantly lower after the 100 ng IL-1β intracerebral injection compared to the 1ng IL-1β injection at P7, P14, P21. In contrast, at P56, the number of neutrophils was significantly higher following the 100 ng compared to the 1ng dose of IL-1β (A). The absence of the window of susceptibility, observed at 4 h, was also absent at 2 h after intracerebral injection of 100 ng IL-1β at P7, P14 and P21 when compared to the 1ng dose at 4 h (neutrophils per mm² of striatum after immunohistochemistry using anti-neutrophil serum counterstained with cresyl violet) (B). Scale bar = 50 µm. ^∗p < .05, ^∗∗p < .01, ^∗∗∗p < .001 and ^###p < 0.001 vs. all 4 h (h) 1ng values. 4 h — P7: n = 4 each group; P14: n = 5 for 1ng IL-1β, n = 3 for 100 ng IL-1β; P21: n = 4 for 1ng IL-1β, n = 3 for 100 ng IL-1β; P56: n = 3 each group; 2 h - P7: n = 6, P14: n = 6 and P21: n = 5.