Induction of γ-H2AX foci in human exfoliated buccal cells after in vitro exposure to ionising radiation

Abstract

Purpose: To test the γ-H2AX (Histone 2AX phosphorylation of serine 139) foci assay for the detection of ionising radiation-induced DNA damage in buccal exfoliated cells.

Materials and methods: Buccal mucosa cells from five individuals (three females, two males, aged 26–47 years) were exposed to 0, 0.5, 1, 2 and 4 Gy of gamma-rays. DNA damage and DNA damage removal were measured using the γ-H2AX foci assay. Lymphocytes from one donor and the nuclear antigen H2B were used as a positive control to test the staining protocol.

Results: In the absence of radiation exposure, no significant differences for both H2B and γ-H2AX signals were detected when comparing buccal cells and lymphocytes. The γ-H2AX foci rate per cell in non-irradiated buccal cells was 0.08 ± 0.02. The number of γ-H2AX foci increased linearly with ionising radiation dose in the interval from 0–4 Gy, and reached a foci rate per cell of 0.82 ± 0.22 at 4 Gy. Incubation experiments after in vitro gamma irradiation revealed that the number of γ-H2AX foci did not show a significant decrease 5 h post exposure under the experimental conditions used.

Conclusion: Data suggest that it is possible to apply the γ-H2AX foci assay for the detection of ionising radiation-induced DNA damage in buccal exfoliated cells. The low removal of ionising radiation induced γ-H2AX foci in buccal cells is a potential advantage for a biological dosimetry application.

Keywords:

• γ-H2AX foci assay
• human buccal cells
• ionising radiation
• biological dosimetry

Acknowledgements

Special thanks go to Professor Michael Fenech for important comments on the scoring criteria and the manuscript. The participants are acknowledged for donating cells samples. Part of this work was supported by IAEA fellowship CUB/08034.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.