Macrophages from rat livers with micronodular and macronodular cirrhosis differ with respect to mediator release and DNA-synthesis

Background/Aims: Liver macrophages play an essential role in necro-inflammatory liver damage which leads to fibrosis and cirrhosis. The aim of the present study was to compare the mediator release and the DNA synthesis of macrophages at an early and at a later stage of liver cirrhosis induced by thioacetamide. Methods: Liver macrophages were isolated by an enzymic digestion method, followed by elutriation. The release of reactive oxygen species and cytokines, and the synthesis of DNA were measured in cultivated cells. Results: The vitality of isolated macrophages from cirrhotic livers was always higher than 98%. The total yield of macrophages was less in micronodular cirrhotic livers and was markedly higher in macronodular cirrhotic livers when compared with age-matched controls. The cellular granules measured by sideward light scattering showed a shift to larger sizes in macrophages from micronodular cirrhotic livers when compared with the controls and the other experimental group. Macrophages from both cirrhosis groups exhibited a markedly higher unstimulated and lipopolysaccharide-stimulated IL-6 production than the controls. The release of TNF-alpha did not differ between controls and the experimental groups. Macrophages from macronodular cirrhotic livers produced higher amounts of nitric oxide but less superoxide anion radicals than the controls. DNA synthesis was 10-12-fold and 3-10-fold higher in macrophages from micronodular and macronodular cirrhotic livers, respectively, when compared with the age-matched controls. Conclusions: The data presented provide evidence that it is possible to isolate and to cultivate macrophages from livers with high yield and vitality at different stages of cirrhogenesis. Our results clearly demonstrate functional differences between macrophages from livers with micro- or macronodular cirrhosis; this finding may be important for the pathogenesis or perpetuation of the cirrhogenetic process.