Fig. 2

In a “prestressed” condition, gut exposure to air pollution particles also induces glucose intolerance and impaired insulin secretion, while lung exposure does not. Mice on high-fat diet (HFD) were concomitantly treated by intratracheal instillation with DEP, PM or PBS. After 4 weeks of treatment, mice were rendered diabetic by a single dose of streptozotocin (STZ, 120 mg/kg). A Schematic illustration of lung exposure model. B GTT in HFD/STZ treated mice 1 week and 1 month after STZ injection. C Body weight over time. D Insulin, body weight and fasting glucose 1 month after STZ injection. E Schematic illustration of gut exposure model. F GTT in HFD/STZ treated mice 1 week and 1 month after STZ injection. G Body weight over time. H Insulin, body weight and fasting glucose 1 month after STZ treatment. I Insulin tolerance test (ITT) one month after STZ injection. Data are presented as mean ± SEM of 5–8 mice per group from one representative experiment each. GTT and insulin values were compared by two-way ANOVA, body weight and fasting glucose by a two-tailed, unpaired Mann–Whitney U test *p < 0.05, **p < 0.01). * indicates significances between 12 µg DEP and PBS controls and & between 12 µg PM and PBS controls