【摘要】 研究酵母β-葡聚糖(BG)对X射线辐照致人脐静脉内皮细胞(Eahy926)损伤的防护作用。用四甲基偶氮唑盐(MTT)法评价BG的Eahy926细胞毒性,筛选出BG的最佳浓度和作用时间(10μg/mL,24 h)。用克隆存活法分析BG对Eahy926细胞辐射敏感性的影响。在X射线辐照至吸收剂量2Gy后0.5和24 h,用流式细胞仪分析细胞凋亡分布、DNA损伤和细胞内活性氧(ROS)水平,并用试剂盒检测超氧化物歧化酶(SOD)活性和过氧化氢酶(CAT)活性。结果显示:BG对Eahy926细胞无毒性作用;与单独辐照组相比,BG预处理能减轻X射线辐射损伤,显著提高X射线辐照后细胞的克隆存活率;辐照后同一时间点,BG预处理组细胞DNA损伤、细胞凋亡率和细胞内ROS水平都明显低于单独辐照组;而BG预处理组细胞SOD和CAT酶活性均明显高于单独辐照组;在辐照后0.5和24 h,BG预处理组DNA损伤修复率高于单独辐照组。结果表明,BG对X射线造成的Eahy926细胞损伤有一定防护作用,其机制可能与BG清除细胞内自由基、提高抗氧化酶活性、减轻DNA损伤和细胞凋亡、促进DNA损伤修复有关。更多还原

【Abstract】 To explore the radioprotective effect of Saccharomyces cerevisiae-derived-beta-D-glucan(BG) on human umbilical vein endothelial cells(Eahy926), cytotoxicity of BG on Eahy926 cells was detected by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide(MTT), and the optimum concentration and pretreatment time were confirmed(10 μg/mL, 24 h). The clone formation assay was used to detect the BG effect on radiosensitivity of Eahy926 cells. At 0.5 h and 24 h after X-ray irradiation at a absorbed dose of 2 Gy, the apoptosis, DNA damage, and intracellular reactive oxygen species(ROS) of Eahy926 cells in each group were measured through flow cytometry, and the enzyme activities of superoxide dismutase(SOD) and catalase(CAT) were also detected. The results showed that BG was non-toxic to Eahy926 cells. BG pretreatment could decrease the cell damage caused by X-rays and significantly increase clone survival rates. At 0.5 h and 24 h after irradiation, the DNA damage, cell apoptosis rates, and intracellular ROS level of the BG pretreatment group were significantly lower than those of the 2 Gy group, and the enzyme activities of SOD and CAT were higher than those of the 2 Gy group. At 0.5 h and 24 h after irradiation, the repair rates of DNA damage in the BG pretreatment group were higher than those in the 2 Gy group. The results indicate that BG has a radioprotection effect on Eahy926 cells, and the mechanism may be attributed to BG’s effect on scavenge of ROS, enhancement of antioxidase activities, reduction of DNA damage and cell apoptosis, and promotion of the repair of DNA damage.更多还原