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为探讨低剂量电离辐射生物效应作用机制,本文研究了不同剂量单次辐照后,人淋巴母细胞基因表达转录谱的变化。采用0.1 Gy、0.5 Gy和1.0 Gy剂量的γ射线照射人淋巴母细胞,未照射细胞为对照组。照射后4 h提取细胞总RNA,用含有45 033个基因的人类全基因组表达谱芯片检测分析。对差异表达基因进行层次聚类分析、基因本体论分析和通路分析,并用实时荧光定量PCR验证。结果表明,3个剂量组均上调表达的基因1330个,下调表达的基因1002个。基因表达量与吸收剂量相关的基因共18个,其中与剂量正相关的基因16个,负相关的基因2个。层次聚类分析结果表明,4个实验组中,0.1 Gy和1.0 Gy照射组差异表达基因相似程度最高。这些差异表达的基因涉及到多条通路,如细胞周期、p53信号通路、碱基切除修复、RNA转运和内质网蛋白加工等。实时荧光定量PCR检测结果表明,CASP9(caspase 9)mRNA在照射后4 h随吸收剂量表达变化与基因芯片检测结果一致。基因芯片筛选出的差异表达基因有助于阐明低剂量辐射生物效应作用机理,与辐射剂量相关的差异表达基因有可能成为低剂量辐射暴露的生物剂量计。
In order to explore the mechanism of biological effects of low-dose ionizing radiation, we studied the changes of transcriptional profiles of gene expression in human lymphoblasts after single-dose irradiation. Human lymphoblasts were irradiated with γ-rays at doses of 0.1 Gy, 0.5 Gy and 1.0 Gy, and non-irradiated cells were used as control. Total RNA was extracted 4 h after irradiation and analyzed by human genome-wide profiling with 45 033 genes. Hierarchical cluster analysis, gene ontology analysis and pathway analysis of differentially expressed genes were performed and verified by real-time fluorescence quantitative PCR. The results showed that 1,330 genes were up-regulated and 1002 genes were down-regulated in the three dose groups. Gene expression and absorbed dose related genes a total of 18, of which there are 16 positive correlated with the dose, negative 2 genes. Hierarchical cluster analysis showed that among the four experimental groups, the highest similarity was found between the differentially expressed genes in 0.1 Gy and 1.0 Gy irradiation groups. These differentially expressed genes involved in multiple pathways, such as cell cycle, p53 signaling, base excision repair, RNA transport and endoplasmic reticulum protein processing. Real-time PCR results showed that caspase 9 mRNA was consistent with the results of microarray assay at 4 h after irradiation. Differentially expressed genes screened by cDNA microarray help elucidate the mechanism of biological effects of low-dose radiation. Differentially expressed genes related to radiation dose may become biological dosimeters for low-dose radiation exposure.