高表达谷胱甘肽过氧化物酶1对阿尔茨海默病细胞模型的作用

目的 将谷胱甘肽过氧化物酶1 (GPX1)重组质粒转染肾上腺嗜铬细胞瘤(PC12)细胞，使其在细胞内高表达，探讨GPX1清除自由基、抗氧化应激的细胞保护作用。 方法 将GPX1重组质粒、pLNCX空载体质粒转染PC12细胞，用新霉素(G418)筛选稳定表达GPX1的PC12细胞，以不同β-淀粉样蛋白(Aβ)25-35浓度诱导PC12细胞48 h，确定最佳Aβ25-35浓度，构建理想阿尔茨海默病(AD)细胞模型。以最佳Aβ25-35浓度分别诱导转染GPX1重组质粒组、转染pLNCX空载体质粒组和正常PC12细胞组48 h，比色法比较其吸光度(A)值。 结果 用G418筛选出了稳定高表达GPX1的细胞克隆。与无Aβ25-35的空白对照组比较，20 μmol/LAβ25-35可使PC12细胞的抑制率显著升高，达24.7％，差异有统计学意义(P＜0.01)，确定Aβ25-35的最佳诱导浓度为20 μmol/L。最佳Aβ25-35诱导浓度诱导各细胞组48h后，与转染pLNCX空载体质粒细胞组和正常PC12细胞组比较，转染GPX1重组质粒细胞组A值明显升高，分别为（0.53±0.02）与(0.44±0.02)，（0.53±0.02）与(0.39±0.07)，均P＜0.01]结论转染GPX1重组质粒可增强细胞清除自由基的能力，逆转Aβ25-35所致的细胞生存率降低。

Protective effect of high expression of glutathione peroxidase on cell model of Alzheimer disease

Objective To study the effects of eliminating free radical and increasing antioxidative capacity of glutathione peroxidase 1(GPX1) on PC12 cells. Methods GPX1 recombinant plasmid and Plncxplasmid were transfected into PC12 cells and PC12 cells highly-expressing GPX1 stably were sieved by G418 solution. PC12 ceils were treated with different concentrations of amyloid β-protein (Aβ25-35) for 48 h, to decide the optimal concentration of Aβ25-35 and construct ideal cell model. GPX1/pLNCX/PC12 group, pLNCX/ PC12 group and PC12 group were treated with optimal concentration of Aβ25-35 ,respectively for 48 h, and their absorbance (A) value by MTT conversion was compared among three groups.Results Cell clone highly expressing GPX1 stably were obtained by G418 selection. The increment of cell inhibition ratio was 24.7 ％ after 20 μmol/L Aβ25-35 treatment for 48 h, compared with control group (P＜0.01). Thus the optimization concentration of Aβ25-35 was 20 μmol/L. After treatment with 20 μmol/L for 48 h, the A value was significantly higher in GPX1/pLNCX/PC12 group than in pLNCX/ PC12 group and in PC12 cells group(0.53±0. 02 vs. 0.44±0.02;0.53±0.02 vs. 0.39±0.07, P＜0.01). Conclusions Transfection of GPX1 recombinant plasmid may protect cell against injury from free radical and reverse the decrease of PC12 cell survival rate impaired by Aβ25-35.