硫氧还蛋白对氢醌细胞毒性的抑制

Inhibitory effect of thioredoxin on cytotoxicity of hydroquinone

目的 氢醌引起细胞凋亡 ,可能是通过降低细胞内巯基水平及升高活性氧水平改变细胞内氧化还原状态。鉴于硫氧还蛋白在维持细胞氧化还原状态平衡上也起着重要作用 ,本研究探讨人硫氧还蛋白(hTRX)对氢醌细胞毒作用有无影响。方法 采用脂质体法 ,将真核表达质粒pVP2 2 hTRX和pVP2 2分别转入人胚肾细胞中 ,并将获得的G4 18抗性单克隆细胞株hTRX12和VP2 2细胞进行Western印迹法分析。分别用荧光探针DCFH DA法、碘化丙啶染色法及MTT法测定活性氧水平、凋亡率及细胞存活率。结果 用不同浓度氢醌处理hTRX12细胞与VP2 2细胞 ,hTRX过度表达可降低氢醌所致的活性氧水平升高 ,降低氢醌诱导的凋亡 ,抑制氢醌的细胞毒性。另外 ,用重组人硫氧还蛋白 (rhTRX)与氢醌同时处理未转染人胚肾细胞 ,也可观察到类似结果。结论硫氧还蛋白可对抗氢醌的细胞毒性 。

AIM Hydroquinone (HQ) induces apoptosis in vitro probably by changing the cellular redox status through reducing the cellular thiol level and increasing the cellular reactive oxygen species (ROS) level. Thioredoxin(TRX) plays an important role in maintaining the cellular redox status. The present study is to investigate if the human thioredoxin(hTRX) will affect the cytotoxicity of HQ. METHODS The eukaryotic expression vectors pVP22-hTRX and pVP22 were introduced into human embryonic kidney cell line (HEK293) by liposome-mediated transfection, and the G418 resistant monocolonies, hTRX12 cells and VP22 cells, were selected. Expression of recombinant gene VP22-hTRX in hTRX12 cells was verified by Western blot. ROS level, apoptosis and cell viability were measured following treatment with HQ in hTRX12 cells and VP22 cells by fluorescence analyzer using DCFH-DA, flow cytometry using propidium iodide, and MTT assay, respectively. RESULTS ROS generation, apoptosis and cell viability decrease caused by HQ could be inhibited by hTRX overexpression. In addition, the recombinant hTRX(rhTRX) had the similar effects on the ROS generation and cell viability decrease caused by HQ. CONCLUSION The results indicated that the hTRX could inhibit the cytotoxicity of HQ by reducing HQ-caused ROS generation and by increasing cellular thiol level.