Pollution of ionising radiation diagnostic dose and its targeted and non-targeted effects on human primary fibroblast cells

Abstract

One of the key issues of current radiation research is the biological effect of low doses of X-ray, which can instigate to chromosomal damage in direct irradiated and bystander cells. Additionally, the direct irradiated and bystander cells demonstrate delayed damage responses within their progeny, underlying radiation-induced genomic instability (GI). In this study we tried to mimic the effects of diagnostic procedure doses of X-ray (0.5 rad) on human fibroblast cells, which are considered as a one of the environmental polluter. Human fibroblast cells were irradiated with 0.5 rad X-ray, which were considered the direct irradiated cells; whilst radiation-induced bystander effects (BE) were induced by media transfer. Both cell populations were propagated until 24 generations for delayed responses. The direct, bystander and their progeny cells were subjected to chromosomal analysis and comet assay to measure chromosomal and total DNA damage in these cells. Early response of chromosome damage was observed in the direct irradiated cells; however it was statistically insignificant. Bystander cells showed higher chromosomal damage than the irradiated cells; but it was insignificant compare to the corresponding control groups. Conversely, comet data demonstrated a significant DNA damage in both direct irradiated and bystander cells as initial responses. Interestingly, progeny of direct irradiated and bystander cells showed a significant chromosomal instability and DNA damage after 24 population doublings following irradiation. The findings suggested that the diagnostic procedure doses of X-ray could cause a profound chromosomal instability within human primary fibroblast cells; which are considered as a hallmark of carcinogenesis.