Acute and chronic imaging of microglia/macrophage response after microhemorrhage.

<p>(<b>A</b>) Maximum intensity projection of 2PEF image stacks of microglia/macrophages (green) and blood vessels (red) before and after microhemorrhage (left). Chronic dynamics of microglia/macrophage behavior after microhemorrhage (right). Inset at right shows reactive processes invading the RBC-filled core (indicated by yellow outline) at 1.5 hr after the lesion. (<b>B</b>) Microglia/macrophage density relative to baseline at different distances from the microhemorrhage as a function of time for homozygous and heterozygous CX₃CR1-GFP mice (p-value compared to control: * <0.05, †† <0.01; analysis of covariance). (<b>C</b>) Maximal distance from the center of the microhemorrhage to the furthest responsive microglia/macrophage as a function of time after the lesion. Red symbol indicates distance to furthest responsive cell after laser ablation in the cortical parenchyma with an energy similar to that used to induce a microhemorrhage. (<b>D</b>) Fraction of microglia/macrophages with processes directed toward the lesion after a microhemorrhage (p-value compared to control for homozygous (heterozygous) mice: * (†) p<0.05, ** (††) p<0.01, *** (†††) p<0.001, # (%) p<0.0001, ## (%%) p<0.00001; Mann Whitney U test). (<b>E</b>) Diameter of region where microglia/macrophages are excluded after microhemorrhage as a function of time. Average RBC core diameter for the heterozygous (homozygous) animals is indicated in green (red) at 0.5 and 1.5 hr post hemorrhage. Error bars represent the standard error of the mean (SEM).