黄芪多糖对X射线辐射所致BMSCs全基因组低甲基化的防护作用

目的 研究黄芪多糖(Astragalus polysaccharide,APS)对多次X线电离辐射(ionizing radiation,IR)所致骨髓间充质干细胞(bone marrow stem cells,BMSCs)全基因组甲基化水平的影响。方法 采用APS作用于5次每次2 Gy X射线辐射的BMSCs,将BMSCs分为对照组、APS组、IR组和APS+IR组。采用胞质分裂阻断法测定微核形成率;细胞染色体核型分析检测细胞核损伤;EPIGENTEK试剂盒检测各组BMSCs全基因组甲基化程度;Westernblotting检测各组BMSCs甲基转移酶DNMT3a、DNMT3b,甲基化CpG结合蛋白2(MeCP2)、甲基化CpG结合域蛋白2(MBD2)和各组BMSCs癌基因c-Myc、H-ras,抑癌基因P53、P16的蛋白表达水平。结果 与对照组比较,IR组微核数目和染色体畸变明显增加(P<0.01),BMSCs全基因组甲基化程度明显降低(P<0.01);与IR组比较,APS+IR组微核数目和染色体畸变减少(P<0.05),BMSCs全基因组甲基化程度升高(P<0.01)。在蛋白表达上,与对照组比较,IR组DNMT3a和MeCP2均明显降低(P<0.01),c-Myc、H-ras的表达明显升高,P53、P16的表达显著降低(P<0.01);与IR组比较,APS+IR组DNMT3a和MeCP2明显升高(P<0.01或P<0.05),c-Myc、H-ras的表达降低(P<0.01),P53、P16的表达显著升高(P<0.01)。结论 黄芪多糖能够防治多次X线辐射所致BMSCs全基因组甲基化水平,降低BMSCs的恶化风险。

Protective Effect of Astragalus Polysaccharide on the Hypomethylation of BMSCs Genome Induced by Multiple X-ray Radiation

OBJECTIVE To study the effect of Astragalus polysaccharide(APS) on the whole genome methylation level of bone marrow stem cells(BMSCs) induced by multiple X-ray ionizing radiation(IR).METHODS APS was used to act on BMSCs irradiated 5 times with 2 Gy X-rays per time, and BMSCs were divided into control group, APS group, IR group and APS+IR group. Cytokinesis blocking method was used to determine the rate of micronucleus formation; cell chromosome karyotype analysis was used to detect nuclear damage; EPIGENTEK kit was used to detect the degree of methylation of the whole genome of BMSCs in each group; Western blotting was used to detect the expression levels of BMSCs methyltransferase DNMT3a, DNMT3b, methyl-Cp G-binding protein 2(MeCP2), methyl-Cp G-binding domain protein 2(MBD2), oncogenes c-Myc, H-ras, and tumor suppressor genes P53 and P16 of BMSCs in each group.RESULTS Compared with the control group, the number of micronuclei and chromosome aberrations in IR group increased significantly(P<0.01), the degree of methylation of the whole genome of BMSCs in the IR group was significantly decreased(P<0.01); compared with IR group, the number of micronuclei and chromosome aberrations in the APS+IR group decreased(P<0.05), the degree of methylation of the whole genome of BMSCs in APS+IR group increased(P<0.01). In terms of protein characterization, compared with the control group, DNMT3a and MeCP2 in IR group were significantly decreased(P<0.01), the expressions of c-Myc and H-ras were significantly increased, and the expressions of P53 and P16 were significantly decreased(P<0.01). Compared with IR group, DNMT3a and MeCP2 in the APS+IR group were significantly increased(P<0.01 or P<0.05), the expressions of c-Myc and H-ras were decreased(P<0.01), and the expressions of P53 and P16 were significantly increased(P<0.01).CONCLUSION APS can prevent and control the methylation level of the whole genome of BMSCs induced by multiple X-ray radiation, and reduce the risk of deterioration of BMSCs.