Study of γ-H2AX as DNA double strand break biomarker in resident living in high natural radiation area of Mamuju, West Sulawesi

Abstract

High expression of phospho histone γ-H2AX, a sensitive marker of double stranded DNA damage, is believed to be an indication of defective DNA repair pathway or genomic instability that may cause mutations and ultimately cancer. DNA damage can be caused by ionizing radiation exposure. Beside in medical treatment/diagnosis or industry, ionizing radiation exposure can also be found in naturally in regions of high natural back ground radiation. In this study we collect the blood from 45 volunteers living in Mamuju, a region with highest natural radiation in Indonesia (dose of ∼7 mSv/year). Subjects were grouped as high natural background area (HNBA) (n = 37) and control area (n = 8). The expression γ-H2AX foci were evaluated by one of researcher fluorescence microscope examination. Our results show that the average foci numbers per cell were in the normal range. While not statistical different, the average of γ-H2AX foci in exposed area higher in the exposed compared to the control area, 0.31 versus 0.13 (p > 0.05), respectively. Moreover, there was also no statistical difference of average γ-H2AX foci between man and woman, old and young people in exposed and control area (p > 0.05). In this preliminary study we find that γ-H2AX foci (and thus DNA double strand break) frequency in residents living in the HNBA of Mamuju, West Sulawesi, show a trend towards higher (albeit not significant) average values relative to the control area. More research is needed to further scrutinize these observations.