The Screening Of Serum Biomarkers In Irradiated Mouse And Serum Amyloid A1 As A Biomarker For Radiation Damage

Aims:After large-scale nuclear and radiation accidents,dose estimation and classified diagnosis of the exposed individuals are the key links to guide medical personnel to treat the wounded in a timely and effective manner.With the rapid development of molecular biology technology,molecular biology methods represented by proteomics technology and lipidomics technology have been paid more and more attention to screen radiation biomarkers for biological dose estimation.This project first screened serum biomarkers of radiation-damaged mice by proteomics and lipidomics techniques.Subsequently,we explored whether SAA1 increased after radiation,the correlation between the increase of SAA1 and radiation-induced death in mice,and the feasibility of SAA1 as a biomarker of human radiation exposure.Methods1.Investigating radiation-responsive proteins using proteomics approaches in the serum samples of mice exposed to 0,2,5.5,7 and 8 Gy,6 h,24 h and 72 h post-irradiation.Based on the fold change and the correlation with irradiated dose,screening the protein biomarker in irradiated mouse.2.Investigating radiation-responsive lipids using lipidomics approaches in the serum samples of mice exposed to 0,2,5.5,7 and 8 Gy,6 h,24 h and 72 h post-irradiation.Based on the fold change and the correlation with irradiated dose,screening the lipid biomarker in irradiated mouse.3.Serum SAA1 levels in C57BL/6J mice receiving TBI(total body irradiation)at 1,2,4,8 and 12 Gy after 0.25,0.5,1,2,3,5 and 7 days was detected by ELISA.4.Serum SAA1 levels in C57BL/6J mice in 10Gy group,10Gy+Amifostine group and Amifostine group was detected by ELISA,and observing the corresponding survival days.5.The serum SAA1 concentration in the 17 nasopharyngeal carcinoma patients after radiotherapy was detected by ELISA.Results1.Proteomics identified a total of 452 proteins in the serum at 6 hours,24 hours and 72 hours after the mice were irradiated with 0,2,5.5,7 and 8 Gy,including 98 radiation-responsive proteins.ORM2,HP,SAA1,SAA2,MBL2,COL1A1 and APCS could be used as protein biomarkers for dose assessment.2.Lipidomics identified 42 lipid molecules in serum at 6 hours,24 hours and 72 hours after irradiation of 0,2,5.5,7 and 8 Gy mice,of which 7 radiation-responsive lipids,including,including PC(18:2/18:2),PC(18:0/18:2),Lyso PC 18:1,PC(18:0/20:4),SM(D18:01 24:1),PC(16:0/18:1)and Lyso PC 18:2,they all could be lipid biomarkers for irradiated mouse.3.A moderate SAA1 increase was observed at 6 hours in serum samples from irradiated mice at all doses used,with a peak at 12 hours,then decreased to day 3 after exposure.And a second SAA1 increase was observed from day 5 to 7 in mouse of 8 and 12 Gy irradiated.4.The cut-off value of the second increase of SAA1 to predict subsequent lethality in 10Gy irradiated mouse was 1.15μg/ml,with sensitivity of 8/17,specificity of 2/3,and precision of 8/9 on day 5,with the sensitivity of 13/16,specificity of 2/3,and precision of 13/14 on day 7.Treatment with amifostine before 10 Gy irradiation could improve the survival rate in irradiated mice and inhibit the second increase of SAA1.5.The serum SAA1 concentration in 17 nasopharyngeal carcinoma patients after radiotherapy(44.63 μg/mL)was considerably higher than the pre-therapeutic concentration(0.54 μg/mL).The ROC curve of SAA1 as a biomarker in discriminating radiation exposure of patients with nasopharyngeal carcinoma showed the area under the curve(AUC)was 0.941±0.05,with a cut-off value of 9.34 μg/mL and corresponding sensitivity of 18/18,specificity of 16/18,and precision of 18/20.Conclusion 1.ORM2,HP,SAA1,SAA2,MBL2,COL1A1 and APCS could be potential protein biomarkers for irradiated mouse.2.PC(18:2/18:2),PC(18:0/18:2),Lyso PC 18:1,PC(18:0/20:4),SM(D18:0/24:1),PC(16:0/18:1)and Lyso PC 18:2 could be potential lipid biomarkers for irradiated mouse.3.SAA1 could be a useful biomarker for the radiation dose estimation in the early stage of radiation damage in a mouse irradiation model.4.SAA1 second increase was successfully identified as a potential biomarker of predicting subsequent lethality of irradiated mouse.5.SAA1 resulted a potential biomarker in human radiation exposure.