摘要目的 研究方格星虫多糖(Sipunculus nudus polysaccharide,SNP)对HUVEC细胞电离辐射损伤的保护作用.方法 采用CCK-8法测定137Csγ射线照射的SNP预处理HUVEC细胞的存活率,筛选获得137Cs γ射线的最佳辐照剂量为8 Gy,SNP的最佳处理浓度为100 g/ml.采用克隆形成法检测SNP预处理后HUVEC细胞的辐照敏感性.采用Hoechst33342和PI双染色法及流式细胞术测定HUVEC细胞凋亡情况.结果 HUVEC细胞存活率随辐射剂量增大而显著下降(P＜0.01);而经一定浓度的SNP预处理后,HUVEC细胞存活率显著上升,且与浓度呈正相关(P＜0.01),当SNP终浓度为100 μg/ml时,存活率最高,由照射后的63.43％上升至84.96％ (P ＜0.01);SNP预处理组的细胞克隆形成率显著高于未处理组(P＜0.01).与辐照模型组相比,SNP预处理的细胞凋亡率和细胞内活性氧(reactive oxygen species,ROS)水平均显著下降,其中凋亡率由15.6％降至6.8％,ROS水平由47.10×104降至41.77×104,差异均有统计学意义(P＜0.05或P＜0.01);Hoechst33342着色的蓝色荧光和PI着色的红色荧光也显著降低(P＜0.01).结论 SNP预处理能提高照射后细胞存活率和克隆形成率,有效降低辐射诱导的细胞凋亡和细胞内ROS水平,表明SNP对电离辐射所致的HUVEC细胞损伤具有较好的保护作用.

abstractsObjective To investigate the protective effect of sipunculusnudus polysaccharide (SNP) on HUVEC cell damage induced by ionizing radiation.Methods The survival rate of HUVEC cells was detected by CCK-8,after irradiation with 137Cs γ-rays and pre-treatment with SNP,and optimal absorption dose rate of 137Cs γ-ray was 8 Gy and optimal concentration of SNP was confirmed to be 100 g/mL.The radiation sensitivity of HUVEC cells pretreated with SNP was detected by clone formation assay.Apoptosis rate of HUVEC cells was measured by Hoechst33342/PI staining and flow cytometry.Results The results indicated that the survival rate of HUVEC cells decreased significantly with the increase of irradiation dose (P ＜ 0.01).When pretreated with SNP,the survival rate of HUVEC cells significantly increased,and it was positively correlated with the concentration of SNP.When the end concentration of SNP was as high as 100 μg/ml,the survival rate reached the highest (84.96％),and the survival rate after irradiation increased from 63.43％ to 84.96％ (P ＜0.01).The rate of clone formation in the SNP-treated group was also significantly higher as compared with that of the control group(P ＜ 0.01).Compared with the irradiation model group,the apoptosis rate and intracellular reactive oxygen species (ROS) levels in the SNP-treated group decreased significantly,with the apoptosis rate decreasing from 15.6％ to 6.8％,and ROS level decreasing from 47.10 × 104 to 41.77 × 104,with statistical signficance (P ＜ 0.05 or P ＜ 0.01).The blue fluorescence of the Hoechst 33342 coloring and red fluorescence of PI coloring also decreased signficantly in the SNP-treated group (P ＜ 0.01).Conclusion The results suggested that SNP pretreatment could increase cell survival rate and cloning rate after irradiation,reduce radiation-induced apoptosis and intracellular ROS levels effectively,indicating that SNP treatment could exert a certain protective effect on HUVEC cell damage induced by ionizing radiation.