(A) Salivary flow rate (SFR) was calculated at pre-irradiation and 2 and 16 weeks post-irradiation. The changes in SFR after irradiation were expressed by the ratio of post-irradiation SFR to pre-irradiation SFR (Mean ± SEM). (B) Time to salivation (lag time, LT) was measured and the ratios of post-irradiation LT to pre-irradiation LT were presented. Data are presented as the mean ± SEM. (A, B and E) Two-way ANOVA, Bonferroni's post hoc test. *, compared to CON in each group; #, compared to IR+PBS in each group. *P < 0.05, **P < 0.01, #P < 0.05. (C) Western blotting of amylase and EGF in saliva at 16 weeks post-irradiation. (D) The salivary amylase activity was examined by the Assay Kit and fold changes in activity level are presented. (E) EGF contents were measured at each time point and the average contents are presented. Data are presented as the mean ± SEM. One-way ANOVA, Tukey's post hoc test. *, compared to CON; #, compared to IR. *P < 0.05, ***P < 0.001, ##P < 0.01. 2 weeks (n = 3 in all groups), 16 weeks CON group (n = 3), IR+PBS group (n = 3), IR+KGF-1 group (n = 2).