Study On The Expression Of S100A4 And IGJ Gene In Human Lymphocyte Strain As A Radiation Biological Dosimetry

ObjectiveThe result of radiation safety assessment, health hazards, and the classification, diagnosis and treatment of various conditions of acute chronic radiation injuries are dependent on radiation dose. How to determine the individual exposure dose after the nuclear accident is an urgent problem which should be solved quickly and precisely.There are a lot of kinds of radiation dosimeters, and some of them can detect the individual radiation dose accurately and quickly, such as physical dosimeter. However the fact that everyone equipped with appropriate physical radiation dosimeter is not realistic during the occurring of a nuclear accident or in the massive crowd radioactive hazard investigation or in some other special working environment. Then a reliable biological dosimeter is needed to accomplish this task.At present, some radiation biodosimeters are commonly used, such as analysis of chromosome aberrations, micronuclei analysis etc. Among them, the analysis of chromosome aberration, which is regarded as a "gold standard", is currently the most widely used method. It is reliable, stable sensitive, and it is the international recognized by IAEA. The chromosome aberration frequency occurred in background exposure is very low, but it can be induced high frequency applied to the external irradiation, and the chromosome aberration is also easy to identify. At present, this method is mainly used in human lymphocytes and some research use skin fibroblasts as the analysis object, either. But the chromosome aberration analysis still has obvious shortcomings in current situation) such as the heavy workload of analysis, the long time it is needed, the high requirements for the analyser, and this method can’t be achieved mass detection in a short time. Therefore, it is urgent to find a more rapid, simple, sensitive biological dosimeter.In recent years, along with the study of molecular mechanism on ionizing radiation-induced DNA damage, we found that ionizing radiation could induce some gene expression changes which belong to transcriptional regulation network, and these genes are known as DNA damage inducible genes. Explore the mechanisms and networks of changes in the expression of these genes are effective ways to find new effects radiation molecular biological markers, even so a good radiation biological dosimeter can be found in this way. Although studies have found that some of the DNA damage induced genes have a good dose effect relationship at present, for more accurate and timely estimating of the individual according to the situation, experts and scholars in the field of radiation biodosimetry thought that about 10-20 DNA damage induced genes were need, which has good biological radiation dosimeter features to compose an array. At present, the number of reliable DNA damage induced genes have been validated for radiation biological dosimeter is unable to meet this requirement, we also need to find more new DNA damage inducible genes which can be the radiation biological dosimeter. Therefore this paper will investigate the S100A4 and IGJ gene, and explore its feasibility as a radiation biological dosimeter on the basis of gene chip.Methods:1. AHH-1 cells was exposed to different doses (0,1,3,5,8,10,15 and 18 Gy) of 60Co y-rays, and its mRNA levels of S100A4 was detected by reverse transcription PCR and real-time PCR at 4,8,12,24,48 and 72 h after irradiation.2. AHH-1 cells was exposed to different doses (0,1,3,5,8,10,15 and 18 Gy) of 60Co y-rays, and its protein levels of S100A4 was detected by Western blotting at 24,48,and 72 h after irradiation.Results:1. Within the range of applied doses, the level of S100A4 gene expression was up-regulated with a good dose-response, the value of R2 is high, and had obvious difference at different time points at 24 h-72 h time points.2. At the transcriptional level, within the range of applied doses, the level of IGJ gene expression was not up-regulated with a good dose-response. Overall, in addition to the individual dose, IGJ gene transcription level with the irradiation dose is increased first and then decreased. In the 0-5 Gy dose range, IGJ mRNA expression increases with the increase of irradiation dose. The results are inconsistent with the gene chip.3. At the protein level, within the range of applied dose (0-3 Gy), the level of S100A4 gene expression was up-regulated with a good dose-response at 24 h and 48 h time points; within the range of applied dose (0-5 Gy), the level of S100A4 protein was down-regulated with a good dose-response at 72 h time-point.Conclusion:1. S100A4 gene expression at transcriptional level could be detected easily and had optimum dose-responses at certain time-points after irradiation.2. IGJ gene expression at transcriptional level could be detected easily and didn’t have optimum dose-responses at certain time-points after irradiation, the relationship between gene expression level and irradiation dose needs further study.3. At the protein level, within the range of applied dose (0-3 Gy), S100A4 gene expression could be detected easily and had optimum dose-responses at 24 h and 48 h time points after irradiation.In summary, the expression of S100A4 gene has the basic character as a biodosimeter. The applicability of IGJ gene expression as a biodosimeter needs further exploration.