Hemin induces higher vascular ICAM-1 expression in Nr4a1^−/−mice. WT mice and Nr4a1^−/− mice were injected with hemin (30 μmol/kg mouse) or phosphate-buffered saline (PBS). (A) Whole mount immunofluorescence analysis of livers 24 hours postinjection showing ICAM-1 (green), CD31/CD144 (red), and 4′,6-diamidino-2-phenylindole (DAPI) (blue). Scale bar = 50 µm. Yellow in “Merge” images indicates colocalization of ICAM-1 (green) expression on CD31/CD144⁺ ECs (red). A pronounced increase in ICAM1 expression was evident due to hemin injection in Nr4a1^−/− mice. (B) Quantification of the area of blood vessels expressing ICAM-1 in the Nr4a1^−/− and control groups using Image J software. Data represent mean ± SEM; means were compared using 2-tailed Student t test. *P < .05; **P < .01; ***P < .001 (n = 6-8 mice per group).