Figure 5. Type I, III, and V collagens from 3-5-di-tert-butyl-4-hydroxytoluene (BHT)-treated mice and the control group at day 28 are shown in histological sections. A, C, E, Control mice showing the normal collagen fibers of types I, III, and V in alveolar interstitium. B, D, F, BHT-treated mice exhibiting a strong green birefringence of collagens I, III, and V in alveolar interstitium of normal areas. G, H, I, BHT-treated mice exhibiting architectural distortion and a diffuse increase of collagens I, III, and V birefringence. J, K, Effects of BHT on collagen types and hydroxyproline detected by immunofluorescence and biochemistry, respectively. Results are reported as area fraction (%) occupied by collagen fibers and as µg/mg hydroxyproline in alveolar interstitum. Data are reported as means±SD, n=20 for the BHT group and n=10 for the control group. P=0.05, BHT vs control (Student t-test). Col: collagen.