Fig. 5.

Modulation of neutrophil recruitment to the brain and blood–brain barrier permeability by activation of the systemic acute phase response at P14. Combined administration of i.c. 1 ng IL-1β and i.v. 100 ng IL-1β resulted in reduced neutrophil recruitment to the brain at 4 h as shown by representative spatial maps of neutrophil distribution in the brain (A) and photomicrographs of immunohistochemistry for neutrophils (brown, anti-neutrophil serum counterstained with cresyl violet) (B). The response was significantly less than when only 1 ng of IL-1β was injected i.c., and was the same as when 100 ng of IL-1β was injected i.c. (C). Representative pictures of blood–brain barrier permeability to endogenous IgG in the 1 ng i.c. + saline or 100 ng i.v. groups show that the combined treatment also reduces blood–brain barrier permeability (D). Scale bar = 50 µm. ^***p < .001. i.v.: intravenous, i.c.: intracerebral. 1 ng i.c./saline i.v.: n = 3, 1 ng i.c./100 ng i.v.: n = 4 and 100 ng i.c.: n = 6. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)