Toxic Effects Of Mercuric Chloride On Human Hepatocyte HL-7702 Cells

Mercuric chloride is an important kind of environmental and industrialpollutant. It is widely used in the manufacture of pesticide, dyestuff, battery,germicides, antiseptics, and so on, which is interrelated to the human life.Liver and kidney are the target organs which HgCl₂ metabolize in and attackon. And, HgCl₂ may induce the toxic effects on organism by differentpathways. It became one of the serious menaces to the public health. In thisstudy, the assays, MTT, SCGE, AO/EB, FCM and immunohistochemistry wereapplied respectively to investigate the influence of HgCl₂ on the biologicaleffects of human hepatocyte strain HL-7702, such as cell proliferation, theDNA damage, the distribution of cell cycle and apoptosis and analyze theeffects of HgCl₂ in this process from the cellular level and the molecular level.The conclusion of the study was shown as:1. HgCl₂ had the toxic effect on HL-7702. Cell proliferation was depressedapparently and the tendency of depression was concentration-dependent(P<0.05). The depression ratio of HL-7702 was gradually up with theextension of culture time. At 16 h, it attained the climax, then, decreaseappreciably.2. HgCl₂ induced the damage of DNA in HL-7702, which showed theconcentration-dependent and the time-dependent effects(P<0.05).3. HgCl₂ interfered in the process of DNA synthesis and the distribution of cellcycle in HL-7702. Treated with HgCl₂, HL-7702 showed G0/G1 arrest and thedecrease of cell number in S phase(P<0.05).4. HgCl₂ induced apoptosis in HL-7702. The percentage of apoptosis increasedwith the concentration of HgCl₂ increasing in HL-7702(P<0.05)5. The results of immunohistochemistry showed that the expression of Fas,FasL, Cyt c, caspase-9, caspase-3 were increased, which were significantlydifferent with those of the control groups(P<0.05), when HL-7702 wereexposed to HgCl2. It suggested that the apoptosis induced by HgCl2 may beinvolved in the death acceptor pathways induced by Fas/ FasL and themitochondrion apoptosis pathways induced cyt C.6. HgCl2 induced the expression of protection protein MT in HL-7702. Theexpression of MT was increased in HL-7702 exposed to HgCl2 and showedthe obvious dependence on the concentration of HgCl2(P<0.05).All in all, HgCl2 can induce the cell toxic effects in HL-7702 cells,including decreasing the activity of enzyme with Sulfhydryl, influencing theprogress of cell cycle, inducing cell apoptosis, and so on. The research has theimportant theoretical meaning and the realistic meaning in studying the toxiceffects of HgCl2 on liver and in investigating its toxic mechanism and theantagonized mechanism.