摘要
目的 研究低剂量电离辐射对转录因子NF κBDNA结合活性的影响 ,探讨NF κB结合活性信号传导通路的机理。方法 采用凝胶电泳移动变化分析及免疫组织化学的方法检测了X射线照射后EL 4细胞NF κBDNA结合活性的时程变化及p65核转位、IκBα水平的变化 ,同时用脂质体介导的瞬时转染法将空质粒和NF κB 荧光素酶表达质粒转染到NIH3T3细胞内 ,并用PKC信号通路阻断剂CalphostinC处理 ,检测受照后其荧光素酶的表达变化。结果 0 0 75GyX射线照射可诱导NF κB、p50 p65和p50 p50活性增强 ,而前者活性增强更明显。这种转录激活能力的增强 ,涉及到辐射诱导的p65核转位和IκBα水平的变化 ,表现为受照后p65亚基核阳性率明显升高 ,而IκBα水平的变化正相反 ,在照后 4h分别达到峰值和低谷。而且PCK信号通路阻断剂CalphostinC可降低 0 0 75Gy照射对NF κB的活化效应。结论 低水平照射诱导NF κB的迅速活化 ,而且可能通过PKC通路 ,进而调节细胞因子等特异基因的表达 ,促使免疫功能增强 ,这可能是低剂量辐射兴奋效应的机理之一。
Objective To observe the effect of low dose radiation (LDR) on the activation of NF-κB and the possible mechanism of its signal tra nsduction. Methods Electrophoretic mobility shift assay (EMSA) and immunohistochemistry were used to detect the changes of DNA-binding activity o f NF-κB and the nuclear translocation of p65 in EL-4 cells,respectively.Meanw hile,LipofectAMINE-mediated transient transfection was used to carry vacant pla smid and NF-κB-luciferase-containing plasmid into NIH3T3 cells,with or witho ut the addition of PKC-specific blocking agent Calphostin C,to detect the expre ssion of luciferase after irradiation. Results X-rays of 0^075 Gy increased the activities of p50/p65 a nd p50/p50 dimers,especially the former.The translocation of p65 into nuclei inc reased and IκBα exhibited the opposite changes.Calphostin C reversed the effec t of 0 075 Gy radiation on the activity of NF-κB. Conclusion The activation of NF-κB induced by LDR might be effec ted via the PKC pathway,resulting in the facilitation of the expression of cytok ines and up-regulation of immune functions,which might be involved in the mecha nisms of excitatory effects of LDR.;
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2003年第6期408-410,共3页
Chinese Journal of Radiological Medicine and Protection
