Has reactive oxygen a role in methylglyoxal toxicity? A study on cultured rat hepatocytes

The toxicity of methylglyoxal and its ability to generate reactive oxygen species were investigated in cultured rat hepatocytes. Under aerobic and anaerobic conditions methylglyoxal increased lactate dehydrogenase (LDH) release and trypan blue uptake in a concentration dependent manner. Those concentrations of methylglyoxal causing cell injury (1 mM <) also caused the release of reactive oxygen species as indicated by peroxidase-catalyzed luminol chemiluminescence. Release of reactive oxygen was detectable only under aerobic conditions, and only became significant when a large portion of the cells had already lost their viability. It is concluded that methylglyoxal injuries cultured rat hepatocytes and induces the generation of reactive oxygen species. The reactive oxygen species, however, are essentially not involved in methylglyoxal hepatotoxicity but are released by already severely injured cells.