Evaluation of Mitotic and Nuclear Division Indexes in Peripheral Blood Lymphocytes of Botteng Village, Mamuju Inhabitants

The biological effects of chronic natural low level ionizing radiation exposure on human population have been a thrust area of study in radiation biology. Botteng village in Mamuju a western coastal city in West Sulawesi, Indonesia, has areas with some of the highest levels of natural radiation measured to date compared to other areas throughout this country. Botteng inhabitants exposed to low radiation dose on their daily basis. Radiation exposure can causes a delay in the cell cycle, thus it will decrease the cell proliferation rate. Aim of this study was to evaluate the mitotic and nuclear division indexes in peripheral blood lymphocytes among people living in Botteng, an area with high natural background radiation in Indonesia. Blood samples were collected from thirty six healthy adult subjects in Botteng and thirteen healthy adult subjects
in normal background radiation area. Mitotic index was calculated as the proportion of metaphase for 500 cells for each sample. By cytokinesis block micronucleus assay the assessment in proportion of mononucleated, binucleated, trinucleated and tetranucleated cells/500 cells were conducted to calculate nuclear division index. Study results showed that in this study the MI (8.98± 2.50 vs 9.09±2.84) and NDI (1.35±0.15 vs 1.40±0.15) in Botteng was lower compared to control group. Statistical analysis revealed that the different was insignificant (P>0.005). It is possible that peripheral blood lymphocytes in Botteng inhabitants were under the toxic effect of mutagenic agent that was probably radon exposure in this study suffer
DNA damages and cannot survive the division cellular cycle that made cells enter in a process of necrosis or apoptosis
before the finish of the first division. This study also showed that there was insignificant difference of MI and NDI in respect to age for all samples. Based on the results in can be concluded that chronic low radiation dose exposure in Botteng has no significant effect on lymphocytes proliferation. Further study using larger sample number should be conduct in further study to ensure the effect of chronic low radiation dose exposure on lymphocytes proliferation.
Keywords: Lymphocytes, Mitotic Index, Nuclear Division Index, Botteng, High background radiation