Endothelial dome formation and microvascular permeability changes in peritoneal venules of WT and Lsp1^−/− mice. Measurements were taken 2 or 4 hours after IL-1β injection into the peritoneum. Image and corresponding image demonstrate endothelial dome formation (filled arrows) and the overlap of endothelial cell borders (open arrow) in Lsp1^−/− mice (A-B) 4 hours after IL-1β injection. Scale bar indicates 500 nm. Image acquisition, panels A-B: Hitachi H-7000 transmission electron microscope; direct magnification: 4000×; 16000 AMT camera, AMT Capture Engine software (V.600.128); images generated with Microsoft Office PowerPoint 2003 (SP3). Percentage quantification of the electron micrograph sections based on the adherent neutrophils per vessel that underwent transendothelial migration with domes in WT vs Lsp1^−/− animals in the cremaster and the peritoneum (C). Twenty to 25 vessel sections per background were analyzed. (D) WT or Lsp1^−/− mice were injected with Evan blue and injected with saline or IL-1β as indicated; 2 or 4 hours after injection, the dye that leaked out into the peritoneum was quantified. *P < .05; ***P < .001. Error bars indicate SEM. e indicates endothelial cell; n, neutrophil; p, pericyte; and L, vessel lumen.