Figure 1

G5 PAMAM dendrimers induce severe acute lung injury. (A) Wet-to-dry weight ratios of the lungs after the administration of nanoparticles (15 μg/g) at 10 hrs after administration. n = 4–6 mice per group. **p < 0.01 compared with the G4-, G5-, G6-, and G7-treated groups and the vehicle control cohort using two-tailed t-test analysis. (B) Survival rates. n = 10 mice per group. **p < 0.01 for the comparison of the G5 group with either the G5.5 or control group. (log-rank test). (C) Arterial blood partial oxygen pressure (PaO₂) and (D) Lung wet-to-dry weight ratios 10 hrs after the intratracheal instillation of the vehicle control, G5.5 (15 μg/g), or G5 (15 μg/g). n = 5 mice per group. **p < 0.01 for the comparison of the G5-treated cohorts with the G5.5-treated and control groups. (two-tailed t-test). (E) Change in lung elastance following a challenge with nanoparticles (15 μg/g) or the vehicle. n = 5–6 mice per group. (ANOVA with Bonferroni post-hoc analysis). (F) Representative images of lung pathology 10 hrs after the administration of the vehicle control or G5.5 or G5 nanoparticles (15 μg/g). The mean number of infiltrating cells per microscopic field ± SEM is also shown. n = 100 fields analyzed for three mice for each treatment group. (two-tailed t-test). Scale bar = 100 μm. (G) Representative images of lungs injected with Evans blue 10 hrs after challenge with nanoparticles (15 μg/g) or the vehicle (control). The amount of extravascular Evans blue was determined 10 hrs after the injection of nanoparticles or vehicle. n = 4–5 mice per group. (two-tailed t-test). Data are shown as the mean values ± SEM, except the survival curve. *p < 0.05 or **p < 0.01.