Damage to F-actin and cell death induced by chromium VI and nickel in primary monolayer cultures of rat hepatocytes.
The toxicity of hexavalent chromium and nickel was investigated using primary cultures of hepatocytes as an in vitro system. Cr VI and Ni are widely used in the steel and orthopaedic implant industry. Although their toxicity has been extensively investigated, the mechanism(s) of action is/are not fully understood. Monolayer cultures of hepatocytes (10(5) cells/cm2) were exposed to various concentrations of Cr VI and Ni for 24 h. Cells were stained with phalloidin-FITC for the detection of the cytoskeletal component, F-actin, and Annexin V-FITC and propidium iodide for the detection of the mode of cell death. Exposure of cells to Cr VI (1, 5, 10 and 50 microM) resulted in the loss of the cell cytoskeleton, and this was accompanied by membrane blebbing and shrinking of the cell. Ni, on the other hand, induced detectable damage to the cytoskeleton only at 500 microM. Staining of the cells with Annexin V and propidium iodide showed that Cr VI induces apoptosis at low concentrations (5 microM), and necrosis at higher concentrations (25 and 50 microM). Ni almost exclusively induced necrosis at 500 microM with very few cells undergoing apoptosis. Below this concentration it had no discernable effect on hepatocytes. Damage to the cell cytoskeleton caused by Cr VI may be an early indication of apoptosis in hepatocytes.
Gunaratnam
Mekala
M
Bioengineering Unit, University of Strathclyde, Wolfson Centre, 106 Rottenrow, Glasgow G4 0NW, UK.
Grant
Mary Helen
MH
D000199:Actins / Q000187:drug effects* / Q000648:ultrastructure; D000818:Animals; D017304:Annexin A5 / Q000031:analogs & derivatives*; D018929:Cell Culture Techniques; D016923:Cell Death; D002478:Cells, Cultured; D002857:Chromium / Q000633:toxicity*; D003599:Cytoskeleton / Q000187:drug effects / Q000473:pathology; D016650:Fluorescein-5-isothiocyanate / Q000031:analogs & derivatives*; D022781:Hepatocytes / Q000187:drug effects* / Q000473:pathology / Q000648:ultrastructure; D018613:Microscopy, Confocal; D009532:Nickel / Q000633:toxicity*; D010590:Phalloidine; D051381:Rats
D000199:Actins; D017304:Annexin A5; C492760:FITC-annexin A5; D002857:Chromium; D010590:Phalloidine; C074702:chromium hexavalent ion; D009532:Nickel; D016650:Fluorescein-5-isothiocyanate