Time-Dependent 53BP1 Foci Kinetics in X-Irradiated Human Hair Follicle Dermal Papilla Cells

The study explored the use of human hair follicle dermal papilla cells (HFDPCs) for biological dosimetry by analyzing 53BP1 foci kinetics after X-irradiation. Results showed that 53BP1 foci increased in a dose-dependent manner up to 5 hours post-irradiation for doses between 50 and 1000 mGy. By 24 hours, foci at 50 mGy returned to baseline, but higher doses maintained dose dependence. Large foci (≥ 1 μm) significantly increased at doses ≥ 3000 mGy at 24 hours. At 96 hours, large-foci assessment remained sensitive for doses as low as 500 mGy. The study suggests that 53BP1 focus counting and size analysis in HFDPCs can estimate radiation doses, supporting their potential use in biological dosimetry and medical triage, with further validation needed using intact hair samples.