RESUMO
CONTEXT: There are plenty of evidence that suggest that the potential high doses of radiation result in severe health effects to exposed individuals, although there is no consensus about the health impact of low dose of ionizing radiation (IR). AIMS: This study aimed to discuss the effect a range of IR doses on the changes of gene expression and serum protein levels of two immune factors transforming growth factor-ß (TGF-ß) and interferon gamma (IFN-γ) in rats. Findings from this study can be useful to develop a suitable biomarker for biological dosimetry applications. SUBJECTS AND METHODS: After 24 h of irradiation of rats with the doses of 1000, 500, 100, 50, and 20 mGy, the gene expression of TGF-ß and IFN-γ in lymphocytes was assessed using quantitative polymerase chain reaction. Besides, the protein level of these two factors in blood plasma was determined by enzyme-linked immunosorbent assay (ELISA) kits. STATISTICAL ANALYSIS USED: One-way analysis of variance Tukey-Kramer Multiple Comparisons Test was used. P <0.05 was considered statistically significant. RESULTS: Significant increases in the expression levels of TGF-ß and IFN-γ genes were observed by increasing the dose from 100 to 500 mGy and then 1000 mGy compared to the control (P < 0.05). The ELISA tests showed significant differences in the serum level of TGF-ß cytokine in the dose of 1000 mGy, while the serum level of IFN-γ cytokine showed significant differences in doses of 20 mGy and 1000 mGy compared to the control (P < 0.05). CONCLUSIONS: The results of this study showed the changes in the expression of TGF-ß and IFN-γ genes after irradiation more than 100 mGy in lymphocytes compared to the control group; the changes in the serum levels of these cytokines only occurred in the specific doses compared to the control group.