Expansion of pericyte gaps and collagen IV LERs in IL-1β-stimulated venular walls.

<p>(<b>A</b>) 3D images of vessel walls in mouse cremaster muscles in the presence and absence of IL-1β revealed pericyte gaps and collagen IV LERs (circled areas) in venules. α-SMA (a marker of venule pericytes and arteriole smooth muscles), collagen IV (a vascular BM marker) and MRP14 (a PMN marker). (<b>B</b>) Cross-sectional images revealed PMNs migrating through pericyte gaps and collagen IV LERs (arrows) in an IL-1β-stimulated venule. (<b>C</b>) Distribution frequency of area of pericyte gaps showed pericyte gap expansion induced by IL-1β (n = 2400). (<b>D</b>) Collagen IV LERs expanded in IL-1β-stimulated venular walls, compared to those in untreated vessels (In each group, n = 1500). (<b>E</b>) The area of pericyte gaps (n = 1500) was plotted against the area of collagen IV LERs (n = 1500). (<b>F</b>) Mean fluorescence intensity (MFI) of collagen IV in LERs decreased after IL-1β injection, indicating thinning of the vascular BM in these areas. (<b>G</b>) MFI of collagen IV in LERs was plotted against the size of pericyte gaps. Bar = 10 µm. t test, ***P<0.001.