Involvement of Calcium, Reactive Oxygen Species, and ATP in Hexavalent Chromium-Induced Damage in Red Blood Cells

Aim: The aim of this study was to investigate the mechanisms of Cr6+-induced red blood cells (RBCs) damage. Methods: The effect of Cr6+ exposure on RBCs was evaluated by hemolytic rate and blood gas assays. After exposure to 20 μM Cr6+, the percentage of phosphatidylserine (PS)-exposing cells, intracellular Ca2+, reactive oxygen species (ROS), and ATP levels were evaluated, and cell morphology was observed. RBCs were exposed to Cr6+ in different Ringer solutions to investigate the role of changes of Ca2+, ROS, and ATP levels in eryptosis and morphology. Results: The Cr6+-induced damage of RBCs was dose-dependent. After a 6 h incubation with Cr6+, RBCs exhibited significant Ca2+ influx, ROS increase, ATP depletion, and PS exposure, but displayed no obvious change in morphology at this time point. After 24 h Cr6+ exposure, the RBCs decreased in size, appeared to be spike-like, and had decreased forward scatter. Inhibition of Ca2+ influx attenuated PS-exposure caused by 6 h Cr6+ exposure, but did not prevent 24 h Cr6+ exposure-induced morphological change in RBCs. Inhibition of rapid ATP consumption using adenine significantly ameliorated Cr6+-caused PS-exposure at 12 h, 24 h and 48 h, and prevented 24 h Cr6+ incubation-induced morphological change in RBCs. Conclusion: Cr6+ can lead to eryptosis. Ca2+ influx, increased ROS levels, and rapid ATP consumption are closely related to Cr6+-induced RBCs damage. Ca2+ influx plays an extremely important role in Cr6+-mediated toxicity