Functional differences between activated and normal rat liver macrophages: LPS uptake capacity by flow cytometric analysis in contrast with TNF-alpha release.

Activated liver macrophages are considered to play an important role in the development of liver injuries. Functional differences between activated and normal rat liver macrophages were investigated. In addition, from the therapeutic point of view, the effects of prostaglandin E1, prostaglandin I2 and E3330 ((2E)-3-[5-(2,3-dimethoxy-6-methyl-1,4- benzoquinoyl)]-2-nonyl-2-propenoic acid) on the functions of liver macrophages were also determined. Rat liver macrophages were primed by Propionibacterium acnes and activated by a small dose of lipopolysaccharide. Lipopolysaccharide uptake capacity was evaluated quantitatively by flow cytometric analysis. Tumor necrosis factor-alpha activities were measured by bioassay. There were no significant differences in lipopolysaccharide uptake capacity between activated and normal liver macrophages, while activated liver macrophages had a significantly (P < 0.01) higher capacity in the release of tumor necrosis factor-alpha. Prostaglandin E1 and E3330 inhibited tumor necrosis factor-alpha release without suppressing lipopolysaccharide uptake capacity. In this study we have clarified the functional differences between activated and normal liver macrophages. The beneficial effects of prostaglandin E1 and E3330 on the functions of liver macrophages were also demonstrated.