RESUMO
INTRODUCTION: In the present study, the radioadaptive role of the immune system induced by low dose (LD) was investigated for its in vivo protective activity. MATERIALS AND METHODS: Quantitative analysis of cytokine gene expression was assessed for their in vivo activity in BALB/c mice. To evaluate the adaptive response induced by LD on the mice spleen lymphocyte, the cytokine interleukin (IL)-4, interferon (IFN)-γ, and transforming growth factor (TGF)-ß expression was measured by a real-time quantitative polymerase chain reaction. To verify the radioadaptive effect of LD, animals were preirradiated at 10 cGy from a 60 Co source and then challenge dose at 200 cGy was delivered. Independent sample student's t-test was employed to compare cytokine gene expression in radioadaptive (10 + 200 cGy), LD (10 cGy), high-dose (HD, 200 cGy), and control groups of animals. RESULTS: Following the HD, the cytokine gene expression of IFN-γ, IL-4, and TGF-ß was significantly decreased compared to the control group (P = 0.0001). However, TGF-ß expression was also decreased significantly in the LD and adaptive groups compared to the control group (P = 0.0001). IFN-γ/IL-4 ratio in the adaptive group was significantly decreased compared to the HD group (P = 0.0001). CONCLUSION: These results indicate that the immune system plays an important role for radioadaptive response induction by LD radiation to adjust the harmful effects of HD irradiation.
Assuntos
Adaptação Fisiológica/imunologia , Imunidade Adaptativa/efeitos da radiação , Regulação da Expressão Gênica/efeitos da radiação , Adaptação Fisiológica/efeitos da radiação , Animais , Células Cultivadas , Relação Dose-Resposta à Radiação , Regulação da Expressão Gênica/imunologia , Interferon gama/genética , Interleucina-4/genética , Masculino , Camundongos , Modelos Animais , Cultura Primária de Células , Linfócitos T/imunologia , Linfócitos T/metabolismo , Linfócitos T/efeitos da radiação , Fator de Crescimento Transformador beta/genética , Irradiação Corporal TotalRESUMO
OBJECTIVES: Nowadays, ionizing radiation (IR) has a significant contribution to the diagnostic and therapeutic medicine, and following that, health risks to individuals through unexpected exposure is greatly increased. Therefore, biological and molecular technology for estimation of dose (biodosimetry) is taken into consideration. In biodosimetry methods stimulation of cells to proliferation is routine to achieve more sensitivity of techniques. However, this concept has recently been challenged by new molecular methods such as gene expression analysis. This study aims to investigate the stimulation effects on gene expression biodosimetry. MATERIALS AND METHODS: The blood samples were taken from15 patients who were irradiated by TC-99 MIBI, before radiopharmaceutical injection and 24 hr after injection. Lymphocytes were extracted immediately and activated by (phytohemagglutinin) PHA for 24 hr and XPA and FDXR expression levels were investigated by employing relative quantitative Real-Time PCR. RESULTS: The results of this study show a significant increase in the FDXR expression level and a significant decrease in the XPA after stimulation of irradiated lymphocytes. Interestingly, a significant increasing trend in the FDXR expression level (at 0.05 significance level) following cell stimulation to the division was observed. CONCLUSION: Our results suggest that the PHA activation role in gene expression-based biodosimetry is strongly depended on the target genes and the relevant protein pathways. Finally, cell stimulation looks to be useful for some specific genes, such as FDXR, due to the increasing trend in expression and improvement of sensitivity of gene expression-based biodosimetry method.
