Figure 9.

Cobalt-induced disruption of blood–brain barrier (BBB) integrity and enhanced vascular permeability. (A1) Capillary from the cerebral cortex of a control mouse (high magnification). Note the single layer of endothelial cells surrounded by a layer of basement membrane, forming an intact BBB. An erythrocyte can be observed in the lumen of the capillary. (A2,A3) Numerous vesicles are present in the cytoplasm of an endothelial cell from the cortex and hippocampus of a cobalt-treated mouse. Microvilli and their fragments (white arrows) are present in the capillary lumen. (A4) The tight junctions were unclear, and basal laminas were partially collapsed. (B,C) Immunohistochemical analysis revealed the presence of albumin within brain tissues. In control mice, albumin immunostaining distinctly showed localization within blood vessels, but in cobalt-treated mice, albumin extravasation (green, indicated by arrows) was observed. Number of mice: n = 5 each. One-way ANOVA. * p < 0.05, **** p < 0.0001. (D) Cross-view images acquired before (Pre-CA) and after (Post-CA) injection showing increased signal intensity (white arrow), indicating BBB leakage. CA = contrast agent.