Fig. 4

Astrocyte coverage surrounding the brain microvessels. a GFAP/collagen type IV double immunofluorescence, labeled astrocytes (GFAP, red) and microvessel basal lamina (collagen type IV, green) in the cerebral cortex and white matter of saline- and LPS-exposed animals [× 10 magnification (top row, scale bar = 100 μm) and × 40 magnification (bottom row, scale bar = 50 μm); nuclear counterstaining DAPI (blue)]. White arrows indicate astrocyte vascular coverage, whereas white arrowheads indicate the microvessels that are not covered by astrocytes. b represents the quantification of astrocytic end-foot coverage in cerebral cortex and white matter of the saline- and LPS-treated groups. Astrocytic coverage expressed as the percent of positive GFAP area overlapping the vessel wall. An average of 15–20 fields per region and per animal and n = 8 in the saline-treated group and n = 7 in the LPS-treated group were analyzed. Statistical analysis by Kruskal-Wallis test follow by Dunn’s post hoc test, *P < 0.05. c Correlations between perivascular astrocytes profiles and vessel density in the cerebral cortex and white matter of the fetal ovine brain. GFAP vascular coverage plotted on the y-axis against the collagen type IV expression as the vascular density in the cerebral cortex (r = 0.13, n = 15, P = 0.64) and white matter (r = 0.70, n = 15, p = 0.004). Solid line is the regression line. Dashed lines are the 95% confidence intervals