Oxidant injury of cultured cells: biochemical consequences

Abstract

The experimental results summarized here suggest a mechanism of oxidant induced cell injury which begins with the generation of DNA strand breaks. The mechanism of the generation of these breaks is currently under investigation. The presence of DNA strand breaks activates pADPr polymerase which causes the conversion of cellular NAD to pADPr and free nicotinamide. It is likely that low levels of NAD are associated with inhibition of glycolysis and thereby contribute to the oxidant-induced fall in cell ATP. Additional factors are likely to contribute to altered cell metabolism following oxidant injury. Hyslop has shown that the Vmax of a critical enzyme of the glycolytic pathway, glyceraldehyde-3-phosphate dehydrogenase, is decreased following exposure to oxidant. Finally, it is likely that the oxidative phosphorylation functions of the mitochondrial membrane may also be perturbed by oxidant injury. The extent to which these alterations in cell metabolism occur in vivo following exposure to oxidants may be of great importance to our understanding of acute inflammatory tissue injury.