Protective role of glycine and kolaviron on lipopolysaccharide-induced alterations of raw U937 cells and U937-derived macrophages

The effect of glycine and kolaviron on lipopolysaccharide-induced U937 cell damage and activation of U937-derived macrophages was studied. U937 cells were incubated with either glycine or kolaviron or both for 24 h before exposure to lipopolysaccharide. Cell viability and production of reactive oxygen species (ROS) were later assessed. In the other experiment, the U937 cells were transformed to the macrophage form using phorbol 12-myristate 13-acetate and incubated with or without glycine or kolaviron or both before exposure to lipopolysaccharide. Production of TNF-α, IL-1, IL-6 and NO were later assessed. The expression of the antioxidant enzymes- superoxide dismutase (SOD) and catalase (CAT) was also evaluated via reverse transcription polymerase chain reaction (RT PCR). It revealed that lipopolysaccharide caused significant cell death and production of reactive oxygen species that was reduced by glycine and kolaviron. Glycine and kolaviron also reduced lipopolysaccharide-mediated secretion of TNF-α, IL-1, IL-6 and NO in U937-derived macrophages. In some cases, pre-incubation of cells with both glycine and kolaviron was better than the individual responses. Glycine and kolaviron also reduced lipopolysaccharide-induced alterations in the expression of SOD and CAT (p<0.05). The study shows that both glycine and kolaviron (either separately or in combination) reduced lipopolysaccharide-mediated alterations in U937 cells and U937-derived macrophages.