Frequency of gamma H2AX foci in healthy volunteers and health workers occupationally exposed to X-irradiation and its relevance in biological dosimetry.
Gamma-H2AX (γ-H2AX) assay is a marker to measure double-strand breaks in the deoxyribonucleic acid. Variables such as age, oxidative stress, temperature, genetic factors and inter-individual variation have been reported to influence the baseline γ-H2AX focus levels. Therefore, knowledge on baseline frequency of γ-H2AX foci in a targeted population would facilitate reliable radiation triage and dose estimation. The objective of the present study was to establish the baseline data using blood samples from healthy volunteers (n = 130) differing in age, occupation and lifestyle as well as from occupationally exposed health workers (n = 20). The γ-H2AX focus assay was performed using epifluorescence microscopy. In vitro dose-response curve for γ-H2AX foci was constructed in blood samples (n = 3) exposed to X-rays (30 min post-exposure). The mean γ-H2AX focus frequency obtained in healthy volunteers was 0.042 ± 0.001 and showed an age-related increase (p < 0.001). Significantly higher (p < 0.005) focus frequencies were observed in health workers (0.066 ± 0.005) than in healthy volunteers. A sub-group analysis did not show a significant (p > 0.1) difference in γ-H2AX focus frequency among sexes. Blood exposed in vitro to X-rays showed dose-dependent increase in γ-H2AX foci frequency (Y = 0.1902 ± 0.1363 + 2.9020 ± 0.3240 * D). Baseline frequency of γ-H2AX foci obtained from different age groups showed a significant (p < 0.01) influence on the dose-response coefficients. The overall results demonstrated that the γ-H2AX assay can be used as a reliable biomarker for radiation triage and estimating the radiation absorbed dose by considering variables such as age, occupation and lifestyle factors.
Department of Human Genetics, Sri Ramachandra University, Porur, Chennai, 600 116, India.
Venkateswarlu
V
Raavi
Department of Human Genetics, Sri Ramachandra University, Porur, Chennai, 600 116, India.
Safa Abdul Syed
SA
Basheerudeen
Department of Human Genetics, Sri Ramachandra University, Porur, Chennai, 600 116, India.
Vijayalakshmi
V
Jagannathan
Department of Neuro Interventional Radiology, Sri Ramachandra University, Porur, Chennai, 600 116, India.
Santosh
S
Joseph
Chemical Radio Protector and Radiation Dosimetry Research Group, Institute of Nuclear Medicine and Allied Sciences, Brig Mazumdar Road, Timarpur, Delhi, 110 054, India.
Nabo Kumar
NK
Chaudhury
Department of Human Genetics, Sri Ramachandra University, Porur, Chennai, 600 116, India. venkip@yahoo.com.
Perumal
0000-0003-2152-2003
P
Venkatachalam
D000293:Adolescent; D000328:Adult; D000368:Aged; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006282:Health Personnel; D064368:Healthy Volunteers; D006657:Histones / Q000378:metabolism*; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism / Q000528:radiation effects; D008297:Male; D008875:Middle Aged; D016273:Occupational Exposure; D011829:Radiation Dosage; D000069079:Radiation Exposure; D014965:X-Rays; D055815:Young Adult
C468783:H2AX protein, human; D006657:Histones
Biodosimetry; Occupational exposure; X-irradiation; γ-H2AX foci