OBJECTIVEThis study was conducted to study the effects of sodium selenite on rat hepatocellular DNA damage, apoptosis, changes of cell cycle and DNA relative content induced by cadmium chloride in vivo.

METHODSBoth sodium selenite at the dose of 5 micromol/kg and cadmium chloride at the dose of 5 micromol/kg, 10 micromol/kg and 20 micromol/kg were given to rats by i.p. and there were 5 male SD rats in each group. Hepatocellular DNA damage was measured by the single cell gel electrophoresis (or comet assay), hepatocellular apoptosis was measured with TUNEL (TdT-mediated dUTP Nick End Labelling) and flow cytometry, DNA relative content (DNA(RC)) and cell cycle were detected with flow cytometry.

RESULTSWhen sodium selenite at the dose of 5 micromol/kg acted jointly with cadmium chloride at the dose of 5 micromol/kg, 10 micromol/kg and 20 micromol/kg respectively, the results showed that selenium reduced the effect of cadmium on DNA damage and apoptosis and decreased the rates of DNA damage and the rates of apoptosis significantly. Sodium selenite at the dose of 5 micromol/kg increased cell number of G(0)/G(1) period decreased by cadmium chloride at the dose of 5 micromol/kg and increased cell number of G(2)/M period decreased by cadmium chloride at the dose of 10 micromol/kg and 20 micromol/kg. Sodium selenite at the dose of 5 micromol/kg increased DNA relative content reduced by cadmium chloride at the dose of 10 micromol/kg and 20 micromol/kg.

CONCLUSIONSIt was suggested that selenium at certain doses could antagonize DNA damage, apoptosis, changes of cell cycle and DNA relative content induced by cadmium in rat hepatocytes in vivo.