Evans blue extravasation in the lung of mice intranasally treated (A) with vehicle (veh, n = 7), LPS (20 μg per mouse, n = 22) or LPS in combination with PGE2 (20 μg per mouse, n = 20). (B) Intranasal treatment with vehicle (veh, n = 5), LPS (20 μg per mouse, n = 7) or in combination with the EP4 receptor agonist ONO AE1-329 (20 μg per mouse, n = 6). Each point shows μg Evans blue (EB) per lung from one animal. Data were analysed using one-way anova and multiple comparisons were calculated with Tukey’s post test. **P < 0.01, ***P < 0.001.