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目的探讨低剂量重金属镉、汞单独及等浓度联合作用对人胚肝细胞(LO2)生长的兴奋效应及可能的机制。方法以体外培养的LO2细胞为实验对象,不同浓度的镉、汞单独及等浓度(0.01~100μmol/L)联合处理LO224 h后,用Vi-CELLTMXR活力分析仪分析细胞生长状况;根据Finney数学模型和Logistic回归方法判断联合作用类型;按照二硫代二硝基苯甲酸比色法和黄嘌呤氧化酶法测定谷胱甘肽过氧化物酶(GSH-Px)与超氧化物歧化酶(SOD)的活力;依据Parvinder Kaur的检测方法检测细胞内ROS水平;火焰原子吸收光谱法及原子荧光法分别检测细胞内镉、汞吸收量。结果低剂量的镉、汞(0.01、0.05、0.25μmol/L)单独染毒及镉+汞(0.01,0.05μmol/L)联合染毒处理24 h能明显刺激LO2细胞生长;Finney数学模型显示镉、汞等浓度联合作用于LO2细胞24 h后Q=1.9,说明其联合作用属于相加作用;低剂量的镉、汞单独及联合染毒LO2细胞24 h均能明显诱导SOD与GSH-Px活力升高,当剂量增大到一定水平(25.6μmol/L)后又抑制两种酶活力。细胞内ROS水平与重金属吸收量随染毒剂量增加而增加。结论低浓度重金属镉、汞单独及等浓度联合作用对LO2生长存在Hormesis效应,其机制可能是低浓度镉、汞诱导细胞GSH-Px、SOD活力增强,清除过量的自由基,保护细胞免受氧化损伤,提高细胞存活率。
Objective To investigate the excitatory effect of low and heavy metal cadmium and mercury on the growth of human embryonic hepatocytes (LO2) and its possible mechanism. Methods LO2 cells cultured in vitro were cultured in the presence of cadmium and mercury at different concentrations (0.01 ~ 100μmol / L) for 24 h. The cell growth was analyzed by Vi-CELLTMXR activity analyzer. According to the Finney mathematical model And Logistic regression method to determine the type of joint action; glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) were determined by dithiobisnitrobenzoate colorimetric method and xanthine oxidase method, The intracellular ROS level was measured by Parvinder Kaur’s detection method. The levels of Cd and Hg uptake were measured by flame atomic absorption spectrometry and atomic fluorescence spectrometry respectively. Results Exposure of low doses of cadmium and mercury (0.01,0.05 and 0.25μmol / L) alone and cadmium + mercury (0.01,0.05μmol / L) for 24 h significantly stimulated the growth of LO2 cells. The Finney mathematical model showed that cadmium , Mercury and other concentrations of LO2 cells 24 hours after Q = 1.9, indicating that the combined effect belongs to the additive effect; low dose of cadmium, mercury alone and combined exposure to LO2 cells 24 h were significantly induced by SOD and GSH-Px activity Increased, when the dose increased to a certain level (25.6μmol / L) and then inhibit the activity of the two enzymes. Intracellular ROS levels and heavy metal uptake increased with dose. CONCLUSION: Hormesis is induced by low and high concentrations of cadmium and mercury in LO2 alone. The mechanism may be that low concentrations of cadmium and mercury induce cell GSH-Px and SOD to increase their activity and eliminate excess free radicals, thereby protecting cells from oxidation Damage, improve cell survival.