Detection And Analysis Of DNA Damage Induced By Different Types Of Radiation

As the science and technology progressing, the understanding of the radiation has increased from physiological levels to cellular and molecular levels. Radiation is divided into ionizing radiation and non-ionizing radiation according to the radiation energy of particles. Heavy ion radiation belongs to ionizing radiation and ultraviolet radiation belongs to non-ionizing radiation. Different types of radiation can produce different biological effects on DNA damage and influence cell morphology, cell proliferation, differentiation, cell signaling pathways and gene expression. The aim of this study is to reveal the effects and molecular mechanism in DNA damage induced by different types of radiation, the characteristic of acute and chronic DNA damage induced by ultraviolet radiation and heavy ion radiation were discussed, dose effects on DNA damage were evaluated, and molecular mechanism in DNA damage induced by different types of radiation were analyzed.In this study, CD4+T lymphocytes were exposure to ultraviolet ray (UVC) radiation and 56Fe heavy ion radiation. Relative fluorescence intensity of yH2AX was used to reflect acute damage and micronucleus formation rate to reflect chronic damage. In addition, I evaluate the dose effects on DNA damage caused by different types of radiation. qRT-PCR was used to analyze the expression levels of miRNAs (miR-22,34a)and western blot was used to analyze the expression levels of apoptosis related genes(Bcl-2 and BAX).The results showed that yH2AX relative fluorescence intensity and radiation dose appeared good linear relationship within low dose (UVC 32J/m2,56Fe 1Gy). Distinct from UVC radiation, heavy ion obviously chronic DNA damage, showing the increased in micronuclei formation rate in a dose-dependent manner and hereditary features. miR-22 expression was significantly increased at 64J/m2 dose of UVC exposure whereas miR-34a expression was changed within 8-32J/m2,56Fe heavy ion radiation resulted in the increase in miR-22 within 0.1-1Gy dose, but decreased miR-34a expression at 0.5Gy dose. These findings suggest that 56Fe and UVC have different effects on miR-22 and miR-34a expression.In addition, compared with the control group, the expression levels of Bcl-2 and BAX did not show obvious changes after UVC radiation, however, anti-apoptotic protein Bcl-2 was down-regulated and pro-apoptotic protein BAX was up-regulated after heavy ion radiation, which revealed that heavy ion radiation induced apoptosis in CD4 cells.The present study demonstrated that the heavy-ion 56Fe iron and UVC ultraviolet radiation can induce acute or chronic injury in CD4 cells while the characteristics and molecular mechanisms were different.This study provides valuable scientific basis for the detection of DNA damage and research on molecular mechanism induced by different types of radiation (UVC and 56Fe) as well as the assessment of radiation exposure risk.