中文摘要：

目的 研究超小尺寸碳量子点（CQDs）在小鼠体内的辐射防护效果,揭示其辐射防护机制.研究机体对CQDs的免疫反应与CQDs的体内毒性.方法 给小鼠注射不同质量浓度的CQDs溶液,采用高剂量γ射线辐照构建小鼠全身辐射损伤模型,通过检测辐照后30 d内小鼠的存活率、骨髓DNA、股骨有核细胞数（BMNC）、超氧化物歧化酶（SOD）和丙二醛（MDA）水平,评估CQDs的辐射防护效果,并探究可能的防护机制.通过检测小鼠注射CQDs前后的体质量变化、肝指数、脾指数,研究CQDs的体内毒性.结果 CQDs对于小鼠具有明显的辐射防护作用.与对照组相比,CQDs处理过的辐照小鼠30 d存活率从0％提高到40％.证明CQDs可有效降低辐照造成的机体造血系统损伤,提高骨髓DNA、股骨BMNC、肝和肺的SOD水平,减少MDA产生.免疫反应结果表明,CQDs的体内毒性较小,不会引发机体的排异反应.结论 CQDs在辐射防护领域具有较大的应用前景,可为新型纳米材料在医学领域的应用提供新思路.

英文摘要：

Objective To study the radioprotective effects of ultra-small carbon quantum dots （CQDs） in mice in vivo,and to reveal the protective mechanism,as well as to study the body immune response to CQDs and the toxicity in vivo.Methods Mice were injected with different concentrations of CQDs solution.Mice models of systemic radiation injury were constructed by high dose gamma rays radiation.The 30-days survival rate,bone marrow DNA,femoral bone marrow nucleated cells （BMNC）,tissue superoxide dismutase （SOD） and malondialdehyde （MDA） were measured to evaluate the radioprotective effects of CQDs,and to investigate the possible protective mechanism.The toxicity of CQDs in vivo was studied by measuring the changes of body weight,liver index and spleen index before and after injections of CQDs in mice.Results CQDs showed obvious radioprotective effects on mice in vivo.Compared with the control group,the 30-days survival rate of irradiated mice treated with CQDs increased from 0% to 40%.CQDs could effectively reduce the hematopoietic system damages caused by radiation,and increase the level of bone marrow DNA,femur BMNC,liver and lung SOD,as well as reduce the production of MDA in liver and lung.The results of immunological reaction tests showed that CQDs had less toxicity in vivo and did not trigger the body immune response.Conclusions CQDs has tremendous application prospects in the field of radiation protection.This study can provide new ideas for the application of new nano-materials in medical field.