THE IMPORTANCE OF SODIUM PYRUVATE IN ASSESSING DAMAGE PRODUCED BY HYDROGEN-PEROXIDE

Instability of hydrogen peroxide solutions was noted during the experi mental exposure of human cells in culture to hydrogen peroxide in expe riments designed to study the production and repair of DNA single-stra nd breaks, A hydrogen peroxide concentrate was diluted into culture me dium, which was then added to experimental cell cultures at various ti mes, with all cultures assessed for DNA damage at 2 h. Only cells trea ted by the first addition had observable DNA damage. This result was u nexpected since these cells had had the maximum repair time. It was de termined that the hydrogen peroxide had been eliminated by the culture medium. To determine the mechanism of this elimination, 200 mu M hydr ogen peroxide was added to various cell culture components, and the so lutions were assayed or hydrogen peroxide after 1 h at 37 degrees C, A lthough most components (except the balanced salts) showed some hydrog en peroxide degradation, it was found that sodium pyruvate was most ef fective, by a wide margin, in eliminating hydrogen peroxide and its to xic effects. This was confirmed by addition of pyruvate to balanced sa le solutions or buffers, and observing the same elimination of hydroge n peroxide, We subsequently found a few earlier reports describing the decarboxylation reaction between hydrogen peroxide and pyruvate, but no kinetic measurements have been published and there seems to be no g eneral appreciation for the very high efficiency of this reaction. The present work presents a preliminary assessment of the importance of p yruvate in the study of hydrogen peroxide and other reactive oxygen sp ecies in mammalian cell culture. Published by Elsevier Science Inc.