Complex chromosomal aberrations induced by low doses of densely ionising radiation in human cells

In collaboration with National Institute of Radiological Sciences (NIRS) heavy ion facility (HIMAC), we have conducted experiments twice with Carbon heavy ion radiation. Human peripheral blood from three healthy donors was exposed to carbon heavy ions at 0.1, 0.25, 0.5 and 1.0 Gy. We have investigated induced DNA damage, the differential gene expression profile, and cytokine and chemokines profile following irradiation. Gene expression profile analysis indicates changes in the expression of genes after exposure. However, it was observed there was more marked expressional changes based on the post irradiation time rather than between the doses. A dose dependent increase in the extent of DNA damage and double strand breaks formation was observed in our study. We also observed changes in the cytokines and chemokines level in the plasma following irradiation. Our study as mentioned in the last year's report exhibited a dose dependent increase in the production of both micronuclei and chromosome aberrations. Studies are being done to investigate the complex chromosome translocations by multi-colour fluorescence in situ hybridization technique. Collectively our results indicate that irradiation with low doses of carbon ion induces varied molecular and cellular changes including chromosomal aberrations. (author)