Protective Effect of Pyruvate upon Cultured Mesothelial Cells Exposed to 2 m<i>M</i> Hydrogen Peroxide

Abstract

Rat peritoneal mesothelial cells in culture have the capability of generating hydrogen peroxide. Exposure of these cells to glucose-enriched, lactated-buffered fluids for peritoneal dialysis significantly increases the production of H(2)O(2). Increased liberation of oxygen radicals also involves the risk of damaging the peritoneal membrane. Pyruvate being a natural oxidant scavenger abundantly present in mammalian cells, we hypothesized that its protective effects facing H(2)O(2) can eventually be of relevance for the mesothelial monolayer of patients on long-term peritoneal dialysis. So far, we designed an experimental study in which rat peritoneal mesothelial cells in culture were exposed to 2 mM H(2)O(2). Cell damage was estimated in terms of decreased capability of the mitochondrial dehydrogenases to reduce MTT. Addition of 2 mM sodium pyruvate to the medium prevented the negative effect of hydrogen peroxide. The MTT/protein values for the control group were 0.00357 +/- 0.00075. The ratio after exposure to 2 mM H(2)O(2) was 0. 00217 +/- 0.00028, whereas that detected in cells incubated in H(2)O(2) plus pyruvate was 0.00325 +/- 0.0082 (p < 0.05). These results indicate that pyruvate protected rat peritoneal mesothelial cells in culture against oxidant injury. These data are one more piece of evidence pointing at pyruvate as a potentially useful buffer for peritoneal dialysis solutions.