• anagen;
  • apoptosis;
  • catagen;
  • fibroblast growth factor;
  • hair follicle dystrophy;
  • ionizing radiation

Abstract:  Radiation-induced hair loss is a clinically important, but under-researched topic. The aim of the study was to develop an in vivo assay system for radiation-induced apoptosis in hair follicles to promote hair research and exploit new radioprotectors. BALB/c mice received total body irradiation (TBI) with γ-rays at doses in the range from 8 to 16 Gy at 6 days after depilation. Pathological changes were detected progressively in the hair follicles over the time course after TBI and the dystrophy was evaluated on the basis of stage-specific parameters reported previously, which were found to be well-suited for classification of the radiation-induced hair follicle dystrophy. As a result, regression from anagen to catagen was determined in these follicles after irradiation. In addition, radiation-induced apoptosis was a good early dystrophic parameter. In this system, it was found that fibroblast growth factor-1 effectively prevented hair follicle apoptosis in mice.