The Role of Oxidative Stress on the Apoptosis of Rat Hepatocytes Induced by Cadmium

【Objective】The role of oxidative stress on the apoptosis of rat hepatocytes induced by cadmium was studied.【Method】Rat hepatocytes were isolated by a two-step perfusion technique.After 24 h planting,hepatocytes were treated with cadmium acetate,or treated with Cd in the presence or absence of Z-VAD-fmk or NAC.Cell viability was measured with MTT assay,the apoptosis,reactive oxygen species(ROS) generation,mitochondrial membrane potential(ΔΨm) collapse were measured by flow cytometry.The hepatocytes homogenate was prepared to detect the levels of caspase-3,malondialdehyde(MDA) and reduced glutathione hormone(GSH) in spectro photometric assay.【Result】 The results showed that cellular viability decreased and apoptosis rate increased significantly or very significantly(P0.05 or P0.01) in a dose-dependent manner after exposure to 2.5,5 and 10 μmol?L-1 Cd.Cd(2.5 and 5 μmol?L-1) induced ROS generation significently in 1.5 hours(P0.05 or P0.01).Cd induced ΔΨm collapse.NAC effectively protected hepatocytes against apoptosis induced by Cd.Cd induced ROS generation and ΔΨm collapse were blocked by NAC(P0.05).The GSH content decreased with the increase of the content of Cd.There was very significant difference in partial groups than the control group at 12 h(P0.01),but GSH content increased with the increase of the dose of Cd at 24 h.The activities of MDA level increased.The caspase-3 activity didn't increase.No effect of Z-VAD-fmk on apoptosis was observed.【Conclusion】These results showed that ROS generation and oxidative stress by Cd triggers apoptosis via caspase-independent pathway.