Search

While the widespread application of ionizing radiation in diagnostic and therapeutic medical procedures is unavoidable, Effects of low doses of ionizing radiation LDIR (low doses of ionizing radiation) are not quite obvious. Moreover, it has been showed that LDIR could affect our immune system. The aim of this study was to appraise the effects of LDIR on the inflammation genes expression levels of the immune system. Balb/C mice were exposed to 20, 50 and 100 mGy WBI by gamma rays from a Cobalt-60 source. Lymphocytes of their spleen were extracted 24 h after exposing the animal for gene expression analysis. IL-4, IFN- γ and TGF- β expression levels were examined by relative quantitative real-time PCR and IFN- γ /IL-4 ratio was evaluated. To compare means values of gene expression the independent samples T -test was performed. The results of this study are evident that low doses of gamma radiation can induce changes on the expression level of the investigated genes and IFN-/IL-4 ratio in Balb/C spleen lymphocytes. A significant reduction of IL-4, IFN- γ and TGF- β genes and an increase of IFN- γ /IL-4 ratio has been induced in the group with 20 mGy of LDIR, while IFN- γ /IL-4 ratio was not changed following to 50 and 100 mGy of gamma irradiation. Our result revealed that 20 mGy dose of gamma radiation can activate protection mechanisms as apoptosis and therefore cause the reduction of investigated genes and immune response shifting to Th1 and thereupon humoral immunity. However no shift to immune response has been observed in the groups which have received doses of 50 and 100 mGy. These results may be of importance to radiation workers and autoimmune patients. There is not any relationship that might lead to a conflict of interest. Mashhad University of Medical Sciences (MUMS) has financially supported this work. [ABSTRACT FROM AUTHOR]

Radioadaptive response (RAR) describes the phenomenan where low dose (called the 'priming dose') of ionizing radiation (IR) reduces harmful effects of subsequent higherdoses of IR (called the 'challenge dose'). The aim of this study was to investigate the role of immune system genes in the adaptive response induced by low-dose of ionizing radiation. Mice were exposed to γ -rays from a 60Co source, to a series of priming and challenge doses at 31 mGy/min and 449 mGy/min respectively. Challenge dose was delivered 24 h following to priming dose. Expression level of two genes; IFN- γ IL-4 were examined by relative quantitative real-time polymerase chain reaction (RT-PCR) in 24 h after exposure. The non-parametric two independent samples T-test were performed to compare mean of gene expression level. The results of this study showed that the gene expression of both IL-4 and IFN- γ values significantly reduced after receiving high doses (P < 0.0001) whereas IL-4 gene expression level increased after low dose. Interestingly, there was no significant difference between IL-4 and IFN- γ genes expression of the adaptive and control group. Gene expression of TGF- β after low and high dose and adaptive group significantly reduced (P < 0.001). The ratio of IFN- γ /IL-4 for high dose group was increased significantly (P < 0.0001). These results are evident for that ionizing radiation may play a role in Th1 and Th2 cytokine expression immune response shift of Th1 cells toward Th2 after low and high dose radiation. Adaptive response to ionizing radiation induced by low dose of gamma ray can reduce the harmful effect of the radiation. There is not any relationship that might lead to a conflict of interest. Mashhad University of Medical Sciences (MUMS) has financially supported this work. [ABSTRACT FROM AUTHOR]