Figure 6. Circadian rhythms in leukocyte recruitment are entrained by photic cues.

(A) Light regime under normal and jetlag conditions as entrained using a light cycler. (B) Quantification of extravasated CD45⁺ leukocytes in the cremaster muscle as analyzed by whole-mount immunofluorescence staining in mice under normal light and jetlag conditions. n = 3–6. (C) Quantification of specific vs. non-specific sphere adhesion in hematopoietic Icam1^−/−/WT BM chimeras under normal light and jetlag conditions. n = 5–6. (D) Quantification of adherent fluorescently labeled cells to BM sinusoids in mice under normal light and jetlag conditions. n = 46–61 areas quantified from 4–5 mice per group. (E–G) Circadian oscillations in Bmal1^−/− mice and control littermates after 3 weeks of constant darkness. (E) Blood leukocyte counts (×10³/µl). n = 4–8. (F) Numbers of extravasated CD45⁺ leukocytes as analyzed by whole-mount immunofluorescence staining of cremaster muscle tissues. n = 24–30 vessels from 4 mice per group. (G) Numbers of adherent fluorescently labeled cells to BM sinusoids after adoptive transfer. n = 22–31 areas quantified from 3 mice per group. (H–J) Representative images (PBS in insets) (H), blood leukocyte counts (×10³/µl) (I) and quantification of TNFα-induced neutrophil infiltration in sections of the cremaster muscle (J) under normal light and jetlag conditions. n = 3–9. (K) Quantification of ICAM-1 protein expression in frozen sections harvested from the same mice. *P<0.05, **P<0.01, ***P<0.001. Scale bar: 50 µm. See also Figure S6.