Study On The Mechanism Of Cytotoxicity Induced By Indium Sulfate In L929Cells

Objective：Indium is a rare metal, which is widely used in information,spaceaviation,energy source,military affairs and medical science. As the indium and indiumcompound being widely used, the population of exposed group has becoming larger.Indium which absorbed through different routes is transported to the soft tissue andbone by blood, and excrete from body by urine and dung. The objective of the researchis to study the cytotoxicity, DNA damage, cytotoxicity mechanism of indium sulfate,and to explore the possible genetic toxicity mechanism, in order to find basis data forexploring effective measures to protect the population health of exposed group.Methods:(1) L929cells were used as the experiment system. Cytotoxicity ofindium sulfate was determined by MTT Cell Proliferation Assay (MTT method) toinvestigate the change of survival rate of cells exposed to different dosages for differentexposure periods, and to investigate the dose-effect relation.(2) Single cell gelelectrophoresis (SCGE) was used to detect the DNA single-strand breaks of cellsexposed to different dosages of indium sulfate.(3) Immunofluorescence (IF) was usedto investigate the DNA double-strand breaks of cells exposed to different dosages ofindium sulfate.(4) DCFH-DA assay was used to study the content of reactive oxygenspecies (ROS) after L929stained by the fluorescent probes which exposed to differentdosages of indium sulfate.(5) JC-1was used to detect the change of mitochondrialmembrane after L929stained by the fluorescent probes which exposed to differentdosages of indium sulfate.Result:(1) As showed in the MTT assay, the absorption of cells (treated24and48hours from the concentration of1mmol/L indium sulfate) turned lower than that ofthe control group, and the difference was significant (P <0.05). As the concentrationincreased, the survival rate of cells showed concentration-dependent relationship.(2)The comet cells ratio elevated as the concentration increased in SCGE exposed to1～4 mmol/L indium sulfate for2and12hours showing significant statistic differences (P<0.05). All the analysis indexes including tail length, Olive tail moment and tail DNA%increased in a dose-dependent pattern.(3) Immunofluorescence showed that focalpoint of γH2AX and its fluorescence intensity increased in L929cells exposed to1～6mmol/L indium sulfate for2hours,and the statistic difference was significant.(4)Levels of reactive oxygen species (ROS) increased as the concentration of indiumsulfate increased and showed a linear correlation by flowcytometry.(5) Levels ofmitochondrial membrane potential (MMP) decreased as the concentration of the indiumsulfate increased (treated for12h), and the statistic difference was significant (P <0.05).Conclusion:(1) Condition in vitro, indium sulfate could inhibit proliferationsignificantly. The survival rate of cells decreased as the concentration of indium sulfateincreased.The result also showed dose-depend relationship.(2) Indium sulfate (treatedfor2h, from the concentration of1mmol/L) could cause single-strand breaks.(3)Indium sulfate could cause double-strand breaks of L929cells.(4) Indium sulfate couldcause the increase of ROS.(5) Indium sulfate reduce the concentration of MMP. Theresults of the study showed that indium sulfate could increase of ROS in L929cells tocause the DNA damage, and reduce the MMP to influence the viability ofmitochondrial.