The use of cyclic voltammetry for the evaluation of oxidative damage in biological samples

A method using cyclic voltammetry to evaluate oxidative damage in biological systems is presented. Three biological systems were tested: Escherichia coli cells, the rat jejunal mucosa, and the enzyme, lactate dehydrogenase. Exposure of E. coli cells to oxidative stress resulted in a rapid decrease in their survival and a decrease in their ability to accumulate ¹⁴C-leucine. This was accompanied by a significant increase in the oxidation potential of the cells. Similar results were obtained when the rat jejunal mucosa was exposed in a perfusion system to oxidative stress induced by the hydroxyl radical produced by either hydrogen peroxide and ferrous ions or the combination of ascorbic acid and copper ions. Loss of cellular potassium was taken as an indication of damage to the rat jejunum. Exposure of lactate dehydrogenase to oxidative stress induced by hydroxyl and peroxyl radicals also resulted in a significant loss of enzyme activity along with a pronounced change in the cyclic voltammogram of the enzyme. It was concluded that measurement of the oxidation potentials of these biological systems can give an indication of the occurrence of oxidative damage.