Micronucleus Assay-based Evaluation of Radiosensitivity of Lymphocytes among Inhabitants Living in High Background Radiation Area of Mamuju, West Sulawesi, Indonesia

Abstract

Naturally occurring radiation can be found all around us and account for most of the radiation received by human beings each year. Indonesia has a region with high-dose natural radiation located in the suburb of West Sulawesi province with a dose rate up to 2800 nSv/h; however, its impact was not fully understood. The aim of this study was to evaluate the radiosensitivity of 12 peripheral blood lymphocytes of inhabitant from high background radiation area (HBRA) and 10 from normal background radiation area (NBRA) based on cytokinesis-block micronucleus (CBMN) assay after challenged with 1.5 Gy of gamma ray. The analysis of CBMN was done according to standard procedure as per IAEA guidelines, and frequency of binucleate (mitotic) cells with micronuclei (MN) was scored in around 2000 binucleate lymphocytes cells per culture in microscopic analysis. Mean MN frequency for HBRA was lower than that of NBRA (0.121 vs. 0.189) after irradiation, indicating an adaptive response in HBRA group that resulted in less radiosensitivity; however, there was no statistically significant different ( P > 0.05) between these two groups. The MN number was higher in women compared to men for both HBRA (0.15 vs. 0.09) and NBRA (0.216 vs. 0.147) groups. Besides, there was no statistically significant difference ( P > 0.05) in Nuclear Division Index (NDI), as measured in 500 metaphase cells with published formula, between HBRA and NBRA samples (1.24 vs. 1.21). The lower MN frequency prompts us to conclude that there is an adaptive response in the lymphocytes of inhabitants as an indicator of lower radiosensitivity to the high natural radiation exposure. Further studies using large number of samples are required to obtain more comprehensive conclusion along with the assessment of other types of radiosensitivity-related biomarkers.

Safety Assessments for Supporting the Application of Nuclear Technology in Indonesia and a Comprehensive Study on High Natural Radioactivity Area

“…Other assessments such as proteomic with mass spectrometry were conducted to determine the research on γ-h2ax, g0, and g2 micronucleus assays. This is in addition to tp53 arg72pro genotyping, nuclear division, mitotic indexes, etc (16) Based on all parameters or biomarkers evaluation and assessment, the natural radiation exposure in MAMUJU failed significantly to affect the health condition of the population under study. Furthermore, there is no significant difference between the study group and its control, which suggests a low risk of natural radiation-exposed related to the induction of any negative impacts (13)(14)(15)(16).…”

“…This is in addition to tp53 arg72pro genotyping, nuclear division, mitotic indexes, etc (16) Based on all parameters or biomarkers evaluation and assessment, the natural radiation exposure in MAMUJU failed significantly to affect the health condition of the population under study. Furthermore, there is no significant difference between the study group and its control, which suggests a low risk of natural radiation-exposed related to the induction of any negative impacts (13)(14)(15)(16). Therefore, a research to protect the affected inhabitants of such areas with improved methodologies is important and urgently needed.…”

Changes in Radiosensitivity to Gamma-Rays of Lymphocytes from Hyperthyroid Patients Treated with I-131

“…To our knowledge, there are no other specific studies indicating the presence of an AR in patients exposed to ionizing radiation for medical reasons. Some studies on AR in humans have only been performed ex vivo on lymphocytes taken from healthy donors [ 10 ] or refer to cohorts of healthy donors from occupational or environmental exposures [ 11 , 12 , 13 , 14 ].…”

The Evaluation of Frequencies of Cytogenetic Biomarkers in Lymphocyte of Residents from High Natural Radiation Area in West Sulawesi, Indonesia

“…These three distinguished endpoints can be analyzed at the same time in this assay [6]. Their frequencies in peripheral blood lymphocytes are formed due to chromosomal aberrations arising under the action of ionizing radiation with a similar formation mechanism [13], [14]. These nuclear anomalies are associated with cancer risk.…”