Fig. 1: Diurnal variation in the proliferation of stromal vascular cells in vivo.

a, b RT-PCR analysis reveals expression of circadian (a) and proliferation (b) genes in the epididymal adipose tissue (eWAT) from lean (gray) and obese (yellow) mice throughout the circadian cycle (n  =  4 animals/zeitgeber time, ZT). mRNA levels for lean mice at ZT0 were set to 1 for all genes. c Diurnal locomotion of mice measured by infrared sensors. White and black arrows indicate the beginning of the light (ZT0) or the dark (ZT12) phase, respectively. d Diurnal food intake of mice fed vivarium chow ad libitum (n = 4 animals/ light or dark period). e Experimental model: 5-ethynyl-2ʹ-deoxyuridine (EdU) was intraperitoneally (IP) injected to lean mice fed ad libitum control chow at ZT0, ZT6, ZT12, or ZT18. eWAT and inguinal adipose tissue (iWAT) stromal vascular cell fractions (SVF) were isolated from fat pads harvested 4 h following EdU injection. f Representative fluorescence activated cell sorting of EdU-positive cells in eWAT-SVF isolated at ZT4 and ZT16, 4 h following a single EdU injection (left panel). Right panel: quantification of fluorescence activated cell sorting of EdU-positive cells from eWAT SVF isolated 4 h following EdU injections at ZT0, ZT6, ZT12, and ZT18 (n = 17 animals in ZT0 and ZT12 and n = 12 animals in ZT6 and ZT18). g Quantification for total EdU⁺ SVF (n = 12–17 animals/ZT) isolated 4 h following EdU injections at ZT0 and ZT12 (left panel) and EdU⁺/CD34⁺/CD31⁻/CD45⁻, EdU⁺/CD31⁺, and EdU⁺/CD45⁺ (n = 10 animals/ZT) SVF (middle and right panels, respectively). Significance (p < 0.05) determined by two-way ANOVA and Sidak’s post-hoc test in a-b; two-tailed Mann–Whitney U test in d and g (middle and right panels); two-tailed unpaired T-test in g (left panel); and one-way ANOVA [F(3, 48) = 4.407] followed by Tukey’s post-hoc test in f.