Toxicity observation. (a) Body weights of mice were plotted and the curve of the Ad-PEDF/Lipo-treated and Ad-null/Lipo-treated group paralleled very closely to that of the Ad-PEDF group and ns group with no significant differences among them (P > 0.05). (b) The Hematoxylin and eosin (H&E) staining of heart, liver, spleen and kidney. After mice were sacrificed histological sections were taken from lungs of mice, and analyzed at × 200 magnification. The organs kept primitively normal without inflammatory cells infiltration and necrosis in each group.