Fig. 4

Separate gut exposure to air pollution particles increases liver lipids and induces gut inflammation in mice fed a standard diet. Wild-type mice were treated with 12 µg diesel exhaust particles (DEP), particulate matter (PM) or PBS 5 times per week via gavage for up to 6 months. A Gene expression of immune cell markers in the colon. B Liver lipids. C Liver enzymes alkaline phosphatase (AP) and alanine transaminase (ALAT). D Inflammatory gene expression in liver tissue relative to PBS treated controls. E Liver macrophages in mice exposed to DEP or PBS via gavage. F H&E staining of liver tissue. G H&E staining of adipose tissue. H Frequencies of adipose tissue macrophages (ATM; F4/80⁺CD11b⁺ among CD45⁺), and their subpopulations defined by CD11c and CD206. I Inflammatory gene expression in adipose tissue relative to PBS treated controls. J Plasma TNF and IL-6. K Cholesterol, high-density lipoproteins (HDL), and triglycerides (TG). Pooled data of 2–3 independent experiments, with each data point representing an individual mouse. *p < 0.05, **p < 0.01, ***p < 0.001, unpaired Mann–Whitney U test with two tailed distribution