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目的探讨氮氧自由基R-1(下称R-1)对人胃上皮细胞GES电离辐射的防护作用。方法应用MTT法检测R-1对GES细胞24 h、48 h和72 h的毒性作用。给予0、1、2、4、8Gy的60Co-γ射线辐照后72 h和12 d分别采用MTT法和克隆形成实验,检测不同浓度R-1对GES细胞辐射防护作用。选取防护效果最佳的0.125μmol/L浓度组对GES细胞进行预处理,给予4Gy的60Co-γ射线照射后的24 h、48 h、72 h分别采用Hoechst33258荧光染色法和流式细胞仪观察GES细胞凋亡。结果与0μmol/L浓度组相比,当R-1的浓度低于1μmol/L时,GES细胞各时间点的吸光值无明显变化(P>0.05),而浓度高于2μmol/L时,其吸光值随浓度的增高下降(P<0.05)。选用0.1、0.125、0.25、0.5、1μmol/L的浓度组检测辐射防护作用,与0μmol/L组相比,R-1各浓度组的吸光值和克隆形成率提高(P<0.05)。故采用辐射防护效果最佳的0.125μmol/L浓度组处理后续实验,与照射组相比,药物+照射组的GES细胞数量明显增多、折光性强、轮廓清晰、微核和核碎裂数量减少、凋亡细胞和凋亡率显著下降。结论 R-1能有效地防护60Co-γ射线对GES细胞的辐射损伤,其辐射防护作用可能与减少细胞凋亡数量相关。
Objective To investigate the protective effect of nitroxide R-1 (R-1) on GES ionizing radiation in human gastric epithelial cells. Methods MTT assay was used to detect the toxic effects of R-1 on GES cells at 24 h, 48 h and 72 h. Radiation protection of GES cells with different concentrations of R-1 was detected by MTT assay and clonogenic assay at 72 h and 12 d after irradiation with 60Co-γ-rays of 0, 1, 2, 4 and 8 Gy respectively. GES cells were pretreated with 0. 125μmol / L with the best protective effect. Goe cells were irradiated with 60Co-γ-ray of 4Gy 24 hours, 48 hours and 72 hours after exposure to Hoechst 33258 fluorescence staining and flow cytometry, respectively Apoptosis. Results When the concentration of R-1 was lower than 1μmol / L, there was no significant change in absorbance at each time point (P> 0.05), while at the concentration of 2μmol / L, Absorbance decreased with increasing concentration (P <0.05). The radioprotective effects of 0.1, 0.125, 0.25, 0.5 and 1 μmol / L were detected. Compared with 0 μmol / L group, the absorbance and the colony formation rate of R-1 increased (P <0.05). Therefore, the radiation protective effect of the best 0.125μmol / L concentration group for subsequent experiments, compared with the irradiated group, the drug + irradiation group of GES cells increased significantly, strong refraction, clear outline, the number of micronuclei and nuclear fragmentation decreased , Apoptotic cells and apoptosis rate decreased significantly. Conclusion R-1 can effectively protect the GES cells from radiation injury induced by 60Co-γ-rays, and its radioprotective effect may be related to the reduction of the number of apoptotic cells.