Post therapy IGF-1 restores functional acinar cell area in irradiated mice. The head and neck region of FVB mice was exposed to a single 5 Gy radiation dose and mice received injections of IGF-1 or vehicle on days 4-8 as depicted in figure 1A. Parotid glands were removed on days 30 (A), 60 (B), and 90 (C) after the radiation treatment. Tissues were embedded into paraffin and immunohistochemistry was performed according to the materials and methods section. The insert is a representative image with amylase-positive acinar cells (green), cytokeratin-positive ductal cells (red), and cell nuclei (blue). The graph represents the percentage area of amylase-positive cells in the field of view. All data are composed of the mean and standard error of the mean from 3-8 mice per group. Significant differences (p < 0.05) were determined using an ANOVA followed by a post-hoc Bonferroni multiple comparison test. Treatment groups with the same letters are not significantly different from each other within the same day.