Figure 6: Lactate attenuated pro-inflammatory cytokine secretion in lipopolysaccharide-activated macrophages. Differentiated THP-1 macrophages were cultured in standard media containing various concentrations of lactic acid. The cells were incubated in untreated (CON) condition or exposed to lipopolysaccharide (100 ng/ml) for 24 h, and the pro-inflammatory cytokine levels were measured. (a) Tumor necrosis factor-α and (b) interleukin-6 production increased upon lipopolysaccharide exposure. The lipopolysaccharide-induced pro-inflammatory cytokine production was attenuated by lactic acid in a dose-dependent manner. *P < 0.05 versus respective CON groups; #P < 0.05 versus lipopolysaccharide + lactic acid 0 mM groups (n = 8/groups).