Fig. 4

Intravenous injection of diesel exhaust particles or carbon black does not cause pulmonary neutrophil accumulation. (i) Example cytospins of cells within bronchoalveolar lavage fluid (BALF) recovered 2, 6 or 24 h following injection of diesel exhaust particles (DEP) or 2 h after intravenous injection of carbon black (CB) solutions. Staining: haematoxylin and eosin, magnification ×400. (ii) Systemic injection of DEP (black bars) or CB (light grey bars) did not increase the total number of cells in BALF. (iii) Differential analysis confirmed that the majority of cells were macrophages, both in saline-treated (white columns) and in particle-treated rats. Data are mean ± s.e.mean (n = 6). All comparisons with saline-treated control were statistically non-significant; P > 0.05 using two-way ANOVA (DEP vs Saline) or Student’s unpaired t-test CB vs Saline)