In vivo study of interferon-γ, transforming growth factor-β, and interleukin-4 gene expression induced by radioadaptive response.

Abstract

In the present study, the radioadaptive role of the immune system induced by low dose (LD) was investigated for its in vivo protective activity. 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)-β 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. Following the HD, the cytokine gene expression of IFN-γ, IL-4, and TGF-β was significantly decreased compared to the control group (P = 0.0001). However, TGF-β 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). 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.