Fig. 5

Evaluating the impact of genetically deleting endothelial β4 integrin on BBB integrity in EAE. a Frozen sections of the medulla oblongata taken from the β4-EC-KO and WT littermate control mice at the acute stage of EAE (day 21) were dual-stained using antibodies specific for the endothelial marker CD31 (AlexaFluor-488, green) and fibrinogen (Cy3, red). Scale bar = 100 μm. b Quantification of fibrinogen leakage in the β4-EC-KO vs. WT littermate mice. Data points represent the mean ± SEM of events observed in the medulla oblongata (n = 4 mice). Scale bar = 100 μm. Note that that in most blood vessels, fibrinogen staining was localized to within the lumen of blood vessels. However, in some blood vessels, fibrinogen staining extended beyond the vascular margin, creating a fuzzy leakage pattern, indicative of loss of vascular integrity. Also note that in the β4-EC-KO mice, fibrinogen leakage was noticeably worse than the WT controls, both in the number and extent of leaky vessels, and this was confirmed by quantification