出版社：Korean Society of Environmental Health and Toxicology
摘要：The production of reactive oxygen species on addition of hexavalent chromium (pota ssium dichromate,KfCr^O;) to lung cells in culture was studied using flow cytometer analysis. A Coulter Epics Profile flow cytometer was used to detect the formation of reactive oxygen species after KzCr.O： was added to A549 cells grown to confluence. The cells were loaded with the dye. 2'. 7' -dichlorofluorescein diacetate,after which cellular esterases removed the acetate groups and the dye was trapped intracellularly. Reactive oxygen species oxidized the dye,with resultant fluorescence. Increased doses of Cr(VI) caused increasing fluorescence (10-fold higher than background at 200 fiM). Addition of Cr(III) compounds,as the picolinate or chloride,caused no increased fluorescence. Electron paramagnetic resonance (EPR) spectroscopic studies indicated that three (as yet unidentified) spectral "signals'' of the free radical type were formed on addition of 20,50,100 and 200 pM Cr(VI) to the A549 cells in suspension. Two other KPR 'signals" with the characteristics of Cr(V) entities were seen at field values lower than the standard free radical value.
