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目的探讨叔丁基对苯二酚(tert-butylhydroquinone,tBHQ)对Chang肝细胞无机砷甲基化代谢的影响。方法将Chang肝细胞密度调整为1×105个/ml,采用25μmol/L tBHQ溶液预处理24 h后,再用5μmol/L的tBHQ溶液和0.1、0.5、1.0和5.0μmol/L亚砷酸钠溶液联合染毒24 h;并采用0.1、0.5、1.0和5.0μmol/L亚砷酸钠溶液单独染毒24 h;并设溶剂对照(三蒸水)。采用超低温捕集-氢化物发生-原子吸收分光光度法分别测定细胞内和培养液中的无机砷(inorganicarsenic,iAs)、一甲基砷(monomethylated arsenic,MMA)和二甲基砷(dimethylated arsenic,DMA)含量,并计算一甲基化率(primary methylation index,PMI)和二甲基化率(secondary methylation index,SMI)。结果随着亚砷酸钠染毒剂量的增加,亚砷酸钠单独染毒组和tBHQ+亚砷酸钠染毒组Chang肝细胞内tAs和iAs含量及Chang肝细胞和培养液中的总MMA含量均升高;亚砷酸钠单独染毒组细胞+培养液总DMA含量之间无差异;tBHQ+亚砷酸钠染毒组细胞+培养液总DMA含量呈上升趋势;0.5μmol/L亚砷酸钠单独染毒组和tBHQ+亚砷酸钠染毒组细胞+培养液中的PMI最高,然后随着亚砷酸钠染毒浓度的升高而逐渐降低;亚砷酸钠单独染毒组细胞+培养液中的SMI呈逐渐降低,而tBHQ+亚砷酸钠染毒组细胞+培养液中的SMI呈逐渐升高趋势。此外,与相同浓度的亚砷酸钠单独染毒组比较,tBHQ+0.5,1.0、5.0μmol/L亚砷酸钠染毒组Chang肝细胞内的tAs和iAs含量较低(P<0.05),而细胞+培养液中总DMA含量、PMI和SMI则较高(P<0.05)。结论高浓度砷暴露能够抑制砷的二甲基化过程;而tBHQ预处理能够增加砷的甲基化代谢,降低肝细胞内砷含量,从而增强Chang肝细胞对无机砷暴露的解毒能力。
Objective To investigate the effect of tert-butylhydroquinone (tBHQ) on the metabolism of inorganic arsenic methylation in Chang hepatocytes. Methods The density of Chang hepatocytes was adjusted to 1 × 105 cells / ml, pretreated with 25 μmol / L tBHQ for 24 h, then incubated with 5 μmol / L tBHQ solution and 0.1, 0.5, 1.0 and 5.0 μmol / L sodium arsenite Solution for 24 h. The cells were exposed to 0.1, 0.5, 1.0 and 5.0 μmol / L sodium arsenite solution for 24 h. Solvent control (triple distilled water) was also used. The concentrations of inorganic arsenic (iAs), monomethylated arsenic (MMA) and dimethylated arsenic (IAA) in cells and in culture medium were determined by ultra-low temperature capture-hydride generation- atomic absorption spectrophotometry DMA) content, and calculate the primary methylation index (PMI) and the secondary methylation index (SMI). Results With the dose of sodium arsenite increased, the content of tAs and iAs in Chang hepatocytes and the total MMA in Chang hepatocytes and culture medium were significantly higher in arsenite-treated and tBHQ + sodium arsenite-exposed groups The content of total DMA in cells and culture medium of tBHQ + sodium arsenite increased. The concentration of 0.5μmol / L arsenious acid Sodium alone and tBHQ + sodium arsenite exposure group cells + culture medium PMI highest, and then with the arsenic trioxide concentration increased the concentration and gradually decreased; sodium arsenite single exposure group cells + The SMI in culture medium decreased gradually, while the SMI in tBHQ + sodium arsenite treatment group + culture medium increased gradually. In addition, the tAs and iAs contents in Chang hepatocytes of tBHQ + 0.5,1.0,5.0μmol / L sodium arsenite exposure group were lower than those of the same concentration sodium arsenite alone exposure group (P <0.05) The total DMA content in cells + culture medium, PMI and SMI were higher (P <0.05). Conclusion High concentrations of arsenic exposure can inhibit the arsenic dimerization process. However, tBHQ pretreatment can increase the methylation level of arsenic, decrease the arsenic content in hepatocytes, and enhance the detoxification of Chang hepatocytes to inorganic arsenic exposure.