Circulating microRNA ( miRNA) in blood has good specificity and stability, which in⁃volved in many biological processes. Screening miRNAs in blood responded to radiation and radio⁃protector by global expression profile could provide reference to utilize circulating miRNA as biomar⁃kers of radiation and targets of radioprotector. Kunming mice were whole⁃body exposed to X rays and carbon ions, then, radiosensitivity of circulating miRNA were detected by qRT⁃PCR analysis. It was found that many kinds of circulating miRNAs responded to radiation, and most of them were closely associated with immune system and hematopoietic system. Among these radiation related miRNAs, let⁃7a, miR⁃223 and miR⁃574 showed obvious radiosensitivity and dose⁃effect, which demonstrated that they were potential biomarkers of radiation. Then, mice were treated with Angelica sinensis pol⁃ysaccharide (ASP) by gavage. The authors studied the radiation protection features of ASP and compared the expression levels of circulating miRNAs between ASP treatedgroup and control group after irradiation. The results showed that ASP significantly protected the immune system and hemato⁃ poietic system of irradiated mice, meanwhile, the expression pattern of some miRNAs was distinc⁃tively different between the ASP treated group and the control group. Those findings indicate that different circulating miRNA has different sensitivity to radioprotector, and they could be possible tar⁃gets of radioprotector against radiation damage.%循环血microRNA（ miRNA）具有很好的特异性和稳定性，并且参与多种生物过程。通过表达谱筛选循环血中对辐射及辐射防护药物敏感的miRNA，可以为循环血miRNA作为辐射标志物及辐射防护药靶提供依据和参考。利用X射线和碳离子束对昆明小鼠进行全身照射，采用实时定量PCR的方法研究了循环血中miRNA对辐射的敏感性，发现循环血中多种miR⁃NA对辐射有响应，并且这些miRNA大多与免疫系统和造血系统密切相关，其中的let⁃7a，miR⁃223和miR⁃574呈现出较强的辐射敏感性和较明显的剂量效应关系，具有作为辐射生物标志物的潜能；并利用当归多糖对小鼠进行灌胃，研究了其辐射防护特性，并且对给药组和未给药组小鼠在辐射处理后循环血中的miRNA表达水平进行了比较。结果表明，当归多糖对辐射处理小鼠的免疫系统和造血系统具有显著的保护作用，给药组循环血中部分miRNA表达变化趋势与未给药组明显不同，循环血中不同的miRNA对辐射防护药物有不同的敏感性，或可作为辐射防护药物药靶使用。
展开▼
