FIG. 4.

Measures of fibrosis in the lungs of the rats at time of euthanasia at 48 weeks after irradiation. Panel A: Hydroxyproline (μg of hydroxyproline/100 mg of wet lung tissue) content of the lung tissue. Panel B: recently synthesized collagen (μg of soluble collagen/ 25 mg of wet lung tissue). Each bar represents the mean (±SEM) for all rats available for analysis (Group 1 n = 4; Group 2 n = 8; Group 3 n = 3, Group 4 n = 5; Group 5 n = 5; Group 6 n = 3; Group 7 n = 4 and Group 8 n = 4). Labeling of the treatment groups is as indicated in the legend to Fig. 2. Six-week control animals were euthanized at the start of the experiment and 48-week controls were euthanized at 48 weeks post irradiation. The asterisks indicate groups that are significantly different from the LR group in each panel.