Oxidant-producing activity of FE(II) in tissue culture media.
Huang-X; Zalma-R; Pezerat-H; Costa-M
Toxicologist 1996 Mar; 30(1)(Part 2):298
Ferrous iron (Fe2+) is able to produce oxidants and may play an important role in diverse pathologies such as tissue aging and cancer. Using electron spin resonance and spin trapping technique, we investigated the role of cell culture medium compositions, and pH, on the formation of oxidants produced by Fe2+ and O2. We found that oxidant formation in distilled water increased proportional to the concentrations of Fe2+ from 50 uM to 5 mM, and then sharply decreased to zero as the concentration of Fe2+ reached 50 mM. This phenomena was observed in several tested cell culture media, and oxidant producing activity for a given concentration of Fe2+ was in an increasing order as follows: complete a-MEM < bicarbonate buffer < distilled water < 10 mM of PBS < 50 mM of PBS < 250 mM of PBS. The concentration of Fe2+ which gave the maximal oxidant-producing activity was shifted higher in proportion to the concentration of PBS, i.e. from 5 mM of Fe2+ to 50 mM when PBS was increased from 10 mM to 250 mM. The disappearance of free radical adducts at higher concentrations of Fe2+ is probably due to the low pH and low oxygen diffusion in the tested media, which can significantly slow down the oxidative reactions. Our studies strongly indicate that pH of the cell culture medium plays a determinant role in Fe2+ -catalyzed oxidant formation, and should be taken into account when testing Fe2+ compounds in biological systems.
Iron-compounds; Tissue-culture; Cancer; Cell-cultures; Oxides; Oxidative-processes; Oxidation; Oxidation-reduction-reactions; Biological-systems
The Toxicologist. Society of Toxicology 35th Annual Meeting, March 10-14,1996, Anaheim, California
New York University, New York, New York