Hexavalent Chromium Induced Oxidative Stress and Toxicity on isolated human lymphocytes

Introduction: The most toxic form of chromium (Cr) in the environment is the oxyanion chromate (Cr (VI)). In this form it is soluble and is transported into the cells. Chromate structurally resemble phosphate and sulfate, and can be transported into cells by the anion carrier.  Methods and Results: In this study, toxicity effects of Cr (VI) on isolated human lymphocytes was studied using accelerated cytotoxicity mechanisms screening (ACMS) technique. Human lymphocytes were isolated from blood of healthy persons using Ficoll-paque PLUS standard method. The trypan blue dye was used to cytotoxicity assay. The mechanistic parameters including reactive oxygen species (ROS), lysosomal membrane destabilization, mitochondrial membrane potential (MMP) collapse, lipid peroxidation, GSH and GSSG levels were assessed after 1, 2 and 3 hrs in potassium dichromate treated lymphocytes. The results indicate that toxicity of Cr (VI) was concentration dependent in human lymphocytes. Cr (VI) significantly (p<0.05) induced ROS production, MMP reduction, lysosomal membrane destabilization and lipid peroxidation in human lymphocytes. There was also a decrease in intracellular GSH and raise in extracellular GSSG levels in Cr (VI) treated lymphocytes.  Conclusion: OOur findings revealed that ROS formation with subsequent cellular damages is the molecular mechanism for Cr (VI) induced human blood lymphocyte toxicity