Sofiati Purnami

Micronucleus assay-based evaluation of radiosensitivity of lymphocytes among inhabitants living in high background radiation area of Mamuju, West Sulawesi, Indonesia

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.

Evaluation on The Supplementation of Fermented Garlic Extract in Protecting Human Lymphocytes In Vitro From The Negative Impact of Gamma-Rays

Garlic ( Allium sativum ) contains a wide range of phytocompounds that produce various responses in human body. However the knowledge on the potential of fermented form of garlic in protecting negative impacts of radiation is very limited. In this research in vitro efficacy of fermented garlic in protecting negative impact of gamma ray was studied using cytogenetic test. A set of culture of human lymphocytes was irradiated with 60 Co gamma rays at dose of 2 Gy (dose rate of 2 Gy/min) and fermented garlic extract at four working concentrations of 0, 125, 250 and 500 mg/mL were added to these cells and then were incubated at 37 o C for 48 hrs. Colcemid was added at 3 hr before harvest to collect metaphase cells and it was done by standard methodology for cytogenetic analysis. The fermented garlic extract significantly (p<0.05) did not exhibited antigenotoxic effect of gamma rays and its effectiveness was same as in control (without extract treatment) group. In contrary all concentration of chemicals (125, 250 and 500 mg/mL) were seemingly tend to induce higher number of dicentric and fragment chromosomes than control under microscopic observation. Mitotic index of the cell that was determined with programmed metaphase finder also did not influenced by garlic addition. It was concluded that aqueous garlic extract did not possesses its efficacy in protecting impact of ionizing radiation.

Establishment of a dose-response curve for X-ray-induced micronuclei in human lymphocytes

The cytokinesis-block micronucleus assay in peripheral blood lymphocytes is an established technique for biodosimetry. The aim of this project was to generate a X-ray induced micronuclei (MN) curve for peripheral blood lymphocytes taken from five healthy donors. The blood samples were irradiated with X-rays of 122 KeV at a dose rate of 0.652 Gy/min to doses of 0.5, 1, 2, 3, and 4 Gy. The blood samples were then cultured for 72 h at 37°C and processed following the International Atomic Energy Agency standard procedure with slight modifications. The result showed that the yields of MN frequencies were increased with the increase of radiation dose. Reconstruction of the relationship of MN with dose was fitted to a linear-quadratic model using Chromosome Aberration Calculation Software version 2.0. Due to their advantages, mainly, the dependence on radiation dose and dose rate, despite their limitation, these curves will be useful as alternative method for in vitro dose reconstruction and can support the preparedness for public or occupational radiation overexposure and protection. The results reported here also give us confidence to apply the obtained calibration curve of MN for future biological dosimetry requirements in Indonesia.