低剂量亚硝酸钠预适应对过氧化氢损伤PC12细胞的保护作用

目的:研究亚硝酸钠(NaNO2)预适应对过氧化氢(H2O2)损伤鼠肾上腺嗜铬细胞瘤(PC12)细胞的保护作用。方法:分别以系列浓度的NaNO2作用PC12细胞24h,细胞的增殖活性采用四甲基偶氮唑蓝(MTT)法和活细胞计数法,用Hoechst 33258染色计数凝集和碎核细胞占细胞总数的百分比为细胞凋亡率。以3mmol/L浓度的NaNO2预适应细胞24h后,加或不加一氧化氮清除剂亚铁血红蛋白(hemo),再用1.1mmol/L H2O2暴露6h,细胞存活率检测用MTT、凋亡检测用流式细胞术和Hoechst 33258/PI染色。比色法测定丙二醛(MDA)含量和酶活性。结果:NaNO2对PC12细胞增殖作用呈典型的β型曲线,最大低促效应出现在第24h,最大低促效应剂量为1.4mmol/L,最大促增殖效应为对照组的156%,未观察到不良效应水平(NOAEL)为6mmol/L,细胞增殖半数抑制率(IC50)值为45mmol/L。用3mmol/L NaNO2预适应24h,然后用1.1mmol/LH2O2暴露6h,细胞增殖活性比单纯H2O2组明显升高(P0.05)。用1.1mmol/L H2O2暴露6h,非预适应组细胞凋亡率为44.9%;3mmol/L NaNO2预适应组细胞凋亡率为19.1%,差异显著(P0.05),这种现象可以被一氧化氮清除剂亚铁血红蛋白(hemo)所抑制。3mmol/L NaNO2预适应组细胞超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性和谷胱甘肽过氧化物酶(GSH-Px)水平升高,MDA含量降低(P0.05)。结论:低于6mmol/L NaNO2暴露能够引起PC12细胞的低促效应。低浓度NaNO2预适应,通过降低细胞脂质过氧化,提高抗氧化酶活性,保护过氧化氢毒害的PC12细胞。亚硝酸盐还原为一氧化氮在细胞保护过程中起关键作用。

Cytoprotective role of low-dose sodium nitrite preconditioning against H_2O_2 induced damage in PC12 cells

AIM:To study the cytoprotective role of NaNO2 preconditioning against H2O2 induced damage in PC12 cells. METHODS: PC12 cells were treated with different concentrations of NaNO2 for 6 h,12 h,24 h and 48 h,respectively. The viability of the cells was measured by MTT method and cell counting. The apoptotic rate of PC12 was determined by Hoechst 33258 staining to calculate the ratio of the cells between concentrated and broken nucleus in the total cell count. PC12 cells were pretreated with NaNO2 at concentrati...