Flavonoids as radioprotectors: histomorphometric and immunohistochemical evaluation of their effects on tongue in rats exposed to gamma radiation

Purpose To evaluate the radioprotective effects of kaempferol on the tongue mucosa of rats exposed to gamma radiation.Materials and Methods Thirty-six adult male albino rats were randomly divided into three groups (n = 12): Group 1 (Control), Group 2 (Radiation), which received whole-body gamma irradiation at a total dose of 20 Gy fractionated as 2 Gy/day, 5 days per week for 2 weeks, and Group 3 (Kaempferol + Radiation), which was given oral kaempferol (2 mg/kg every 2 days for 5 doses over 10 days; total dose: 10 mg/kg) before irradiation. Tongue specimens were subjected to histological, histochemical, and immunohistochemical examinations. Morphometric parameters were statistically analyzed.Results Gamma irradiation induced marked epithelial thinning, papillary blunting of the conical projections, disorganization of collagen fibers, and severe inflammatory cell infiltration, accompanied by strong p53 immunoexpression. Kaempferol pretreatment significantly preserved epithelial thickness, maintained papillary architecture, and reduced inflammatory infiltration. The kaempferol-treated group demonstrated more organized, wavy collagen fibers and reduced p53 expression compared with the radiation group. Significant differences were observed among groups regarding collagen area percentage, epithelial thickness, and p53 immunoreactivity (p < .001). These effects are mediated, at least in part, through attenuation of p53-dependent apoptosis.Conclusion Kaempferol effectively mitigates radiation-induced histological and molecular alterations in the tongue mucosa, supporting its potential role as a radioprotective agent during head and neck radiotherapy.