Radiation exposure lymphocyte damage assessed by γ-H2AX level using flow cytometry

Area of Science:

• Radiation Biology
• Molecular Biology
• Biomedical Science

Background:

• DNA double-strand breaks (DSBs) are critical DNA damage lesions induced by ionizing radiation (IR).
• γ-H2AX foci in lymphocytes serve as a reliable biomarker for quantifying DSBs.
• Assessing IR-induced DNA damage and recovery is crucial for understanding radiation effects.

Purpose of the Study:

• To investigate IR-induced DNA damage in mice using γ-H2AX fluorescence analysis via flow cytometry (FCM).
• To quantitatively assess DNA damage and recovery following both external and internal irradiation.
• To evaluate the efficacy of FCM as a method for measuring IR-induced DNA damage.

Main Methods:

• Quantification of γ-H2AX levels in CD4/CD8/B220-positive lymphocytes using mean fluorescence intensity (MFI) by FCM.
• Assessment of dose-dependency and temporal changes of MFI values in vitro and in vivo after external irradiation.
• Evaluation of DNA damage and recovery at 1h and 24h post-internal irradiation with I-131 sodium iodide, including blood-absorbed dose estimation.

Main Results:

• External radiation exposure damage showed a positive correlation with absorbed radiation dose.
• Lymphocytes demonstrated recovery from external irradiation-induced damage within 3 days.
• Internal low-dose irradiation-induced DNA damage was found to recover within 24 hours.

Conclusions:

• Flow cytometry is an effective method for quantitatively assessing DNA damage induced by ionizing radiation.
• γ-H2AX fluorescence analysis by FCM provides a sensitive and reliable measure of IR-induced DNA damage in lymphocytes.
• The study demonstrates the utility of FCM in evaluating both acute and recovery phases of DNA damage from external and internal radiation sources.