Iodoacetonitrile Induced Oxidative Stress in Three Types of Human Hepatocytes

Objective To study the characteristics and mechanism of toxic effects of iodoacetonitrile (IAN) on human hepatocytes,and select suitable cells for examining the toxic effects of environmental pollutants.

Methods After IAN exposure at various concentrations,human liver cancer cells (HepG2) and human normal liver cells (Chang Liver and LO2) were observed for the morphological changes under microscope and detected for cell viability with Cell Counting Kit-8(CCK-8) and intracellular level of reactive oxygen species (ROS),antioxidant response element (ARE) luciferase reporter gene activity,glutathione (GSH) content,and superoxide dismutase (SOD) activity simultaneously.

Results ①The morphology of the three types of human hepatocytes in the 50 μmol/L groups showed round and shrinking cells with fuzzy cell edges and disappeared intercellular junctions;the 100 μmol/L groups showed massive apoptosis.② The viability of HepG2 decreased significantly in the 100 μmol/L group (P<0.05).The viability of Chang liver decreased with higher concentrations of IAN (r=-0.974,P<0.05) and compared with control group,the viability of Chang liver decreased significantly when the concentration of IAN was over 20 μmol/L (all Ps<0.05).The viability of LO2 increased in the 10 μmol/L group (P<0.05) while decreased in the 50 μmol/L and 100 μmol/L groups significantly (both Ps<0.05).③ In the 100 μmol/L groups,the levels of ROS of the three types of human hepatocytes were higher than that of the control group (all Ps<0.05).Among them,the intracellular ROS of HepG2 increased slightly.④ The ARE reporter gene activity varied depending on the concentration of IAN (r=0.944,P<0.05) and increased significantly in the 5 μmol/L groups and the 10 μmol/L groups (both Ps<0.05).⑤ The activities of SOD in the three types of human hepatocytes all decreased (all Ps<0.05) in the 20 μmol/L group,but the SOD in Chang liver cells increased (P<0.05) in the 1 μmol/L group.⑥ The changes of GSH in three human hepatocytes were not significant (all Ps>0.05).

Conclusion The cytotoxicity of IAN on the three types of human hepatocytes can be caused by oxidative stress.Compared to HepG2,Chang Liver and LO2 are more sensitive to the toxicity of IAN and suitable to be the cell models for studying toxic effects of environmental pollutants.