二甲双胍减轻听神经细胞株HEI-OC1放射性损伤的实验研究

Protective effect of metformin against radiation-induced cytotoxicity in an auditory cell line HEI-OC1

目的探讨二甲双胍对听神经细胞株HEI-OC1放射性损伤的保护作用及可能的分子机制。方法体外培养听神经细胞株HEI-OC1,实验分为正常对照组、照射组、照射+二甲双胍干预组(干预组),MTT法检测各组细胞的生长曲线,流式细胞术检测各组细胞的凋亡率,超氧化物歧化酶(SOD)和丙二醛(MDA)检测试剂盒检测氧化应激指标的改变,免疫印迹检测凋亡相关蛋白Bax及Bcl-2的表达。结果照射后HEI-OC1细胞的生长受到抑制,不同浓度的二甲双胍干预能够减轻照射导致的细胞生长抑制。正常对照组、照射组及干预组细胞凋亡百分比分别为(2.58±0.21)%、(8.92±0.19)%、(3.69±0.18)%,提示二甲双胍干预后显著减少了照射引起的细胞凋亡,且凋亡因子Bax和Bcl-2的蛋白表达也较照射组明显降低(P<0.05)。与正常对照组相比,照射组SOD活性下降[(0.82±0.08)U/mg vs(2.36±0.12)U/mg],MDA含量增加[(1.36±0.15)nmol/mg vs(0.61±0.09)nmol/mg],而采用二甲双胍干预后,SOD活性上升(1.91±0.13)U/mg,MDA含量有所下降(0.78±0.10)nmol/mg,差异均有统计学意义(P<0.05)。结论二甲双胍能够减轻射线对听神经细胞的放射性损伤,该损伤机制与二甲双胍对氧化应激反应的抑制有关。

Objective To investigate the protective effect of mefformin against radiation-induced damage in auditory cell line HEI-OC 1 and the possible molecular mechanisms. Methods Experimental groups include：control, radiation, irradiation ＋ metformin. Cell viability was determined using MTT cell proliferation assay. Oxidative stress and apoptosis were assessed by flow cytometry analysis, reactive oxygen species （ROS） measurement, and western blotting. Results After irradiation, the cell viability was inhibited compared with the control group, while treated with different concentrations of mefformin reduced radiation-induced cell growth inhibition. The apoptosis ratios of the normal control group, irradiation group and intervention group were （2.58±0.21）%, （8.92±0.19）%, （3.69±0.18）%, respectively. This result suggested that mefformin intervention significantly reduced the apoptosis induced by irradiation, and the protein expression of Bax and Bcl-2 was distinctly lower than irradiation group （P〈0.05）. Compared with the control group, irradiation group decreased the activity of SOD （0.82±0.08）U/mg vs （2.36±0.12）U/mg, increased the content of MDA （1.36±0.15）nmol/mg vs （0.61±0.09） nmol/mg, while treated by mefformin, SOD activity increased （1.91±0.13） U/mg and the content of MDA decreased （0.78±0.10） nmol/mg. The differences were statistically significant （P〈0.05）. Conclusion We propose that mefformin protects against radiation-induced eytotoxicity by limiting ROS production and preventing apoptosis.