Figure 1.
H&E staining shows pathological alterations that are characteristic of acute lung injury at 6 h after LPS instillation.
A: The gross appearance showed yellow FITC-Dextran on the pulmonary surface after i.n. instillation with 10 mg of FITC-Dextran/kg body weight (b.w.) for 1 hour. The lungs of the LPS model group showed red dots and swelling. B: Representative normal lung histology. C: Lung edema (arrow) and alveolar wall thickening (arrow head) in the ALI mice. D: Infiltration of many inflammatory cells (arrow shows neutrophils) in the ALI mice induced with i.n. instillation with 0.5 mg of LPS/kg b.w. for 6 h (n = 4). B, C, D the magnification is 400X.
Figure 2.
Pulmonary permeability assessed by FITC-Dextran via i.n. instillation.
A: Lung permeability assay using 10 mg of FITC-Dextran kg b.w. via i.n. instillation in the ALI induced by different doses (0.5, 2 and 4 mg/kg b.w.) of LPS by i.n. instillation (n = 3). The fluorescence intensity (FI) of the FITC-Dextran in the plasma showed a dose-dependent increase following the different doses of LPS. B: Lung permeability assay using different doses (1, 3, 15 and 30 mg/kg b.w.) of FITC-Dextran via i.n. instillation in the ALI induced by 0.5 mg of LPS/kg b.w. by intranasal instillation (n = 3, *P<0.05, **P<0.01).
Figure 3.
Lung permeability evaluation in the i.p. or i.n. LPS-induced ALI model by FITC-Albumin and FITC-Dextran assay.
A: The FI value of plasma FITC-Albumin (5 mg/kg b.w., via i.n. instillation) in the ALI induced i.n. by LPS (0.5 mg/kg b.w.). B: Similar fold changes were found between FITC-Dextran (10 mg/kg b.w., via i.n. instillation) and EB (20 mg/kg b.w., via i.v. instillation) in the 6 h and 24 h LPS (4 mg/kg b.w., via i.n. instillation) groups compared to the control groups. C: Lung inflammatory lesions and thickened alveolar septa observed in ALI induced by LPS i.p. (15 mg/kg b.w.) (200X magnification). D: The concentration of plasma FITC-Dextran is significantly increased in the LPS i.p. group compared to the control group, with 10 mg of FITC-Dextran/kg b.w. via i.n. instillation (n = 3, *P<0.05, **P<0.01).
Figure 4.
Lung permeability evaluation by traditional methods.
A: Protein concentration in the BALF. B: The lung wet-to-dry weight ratios in mice with i.n. instillation with 0.5 mg of LPS/kg b.w. C: PMN count in the lung interstitium. D: PMN count in the BALF of mice with i.n. instillation with 0.5 mg of LPS/kg b.w. (n = 4, *P<0.05; **P<0.01).