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Updated: Jun 10, 2026
A Simple and Efficient Method to Isolate Macrophages from Mixed Primary Cultures of Adult Liver Cells
Published on: May 24, 2011
Stimulation of in vitro rat hepatocyte proliferation by conditioned medium obtained from an immortalized macrophage
E Piatti1, M Righi, L Marabini
1Department of Pharmacology "E. Trabucchi", School of Medicine, University of Milan, Via Vanvitelli, 32, 20129 Milan, Italy.
Abstract:
The hepatomitogenic effect of conditioned medium (CDM), obtained from the N-11 mouse macrophage cell line was analysed in rat hepatocyte primary cultures. CDM concentrations from 0.01% to 100% were used and the stimulating action in terms of mitotic index (MI) was evaluated. A clear mitogenic effect was observed only with concentrations higher than 10% with peak effects around 60%. Further increase in CDM concentrations resulted in an MI decrease, and at 100% CDM the effect was totally abolished. Tests addressed to identify the presence of hepatocyte growth factor (HGF) yielded negative results. In order to identify the mitogenic factor(s) involved, we tested CDM obtained after lipopolysaccharide (LPS) stimulation of N-11 cells. Comparison of the results obtained with untreated or LPS stimulated CDMs suggested that macrophage activation does not affect the release of hepatomitogenic activity. To further characterize this macrophage-derived activity, we checked whether CDM could interact with the mitogenic effects of epidermal growth factor (EGF). CDM (10 or 50%) showed no stimulatory effect to hepatocytes cultured in the presence of a maximally stimulatory concentration of EGF. Conversely, both CDM concentrations were able to increase the MI of hepatocyte cultures treated with a suboptimal dose of EGF. These results suggest that macrophages release factor(s) which interact, in hepatocytes, with the EGF signal transduction mechanisms, or with the EGF receptor itself.
Insights
Mouse macrophages release factors that stimulate liver cell division (mitogenesis). This macrophage-derived activity enhances the effects of epidermal growth factor (EGF) on hepatocytes, suggesting interaction with EGF signaling pathways.
Area of Science:
- Cell biology
- Hepatology
- Immunology
Background:
- Macrophage-derived factors can influence liver cell proliferation.
- Understanding these factors is crucial for liver regeneration research.
Purpose of the Study:
- To investigate the hepatomitogenic potential of conditioned medium (CDM) from N-11 mouse macrophages.
- To explore the interaction of macrophage-derived factors with epidermal growth factor (EGF) signaling in hepatocytes.
Main Methods:
- Primary rat hepatocyte cultures were treated with varying concentrations of N-11 cell CDM.
- Mitotic index (MI) was assessed to quantify mitogenic effects.
- Hepatocyte Growth Factor (HGF) presence was tested; CDM from LPS-stimulated macrophages was also evaluated.
Main Results:
- CDM exhibited a dose-dependent hepatomitogenic effect, with peak activity at 60% concentration; higher concentrations reduced this effect.
- Hepatocyte Growth Factor (HGF) was not detected in the CDM.
- Macrophage activation via lipopolysaccharide (LPS) did not alter hepatomitogenic activity.
- CDM potentiated the mitogenic effect of suboptimal doses of epidermal growth factor (EGF) in hepatocytes.
Conclusions:
- Macrophages release hepatomitogenic factors independent of HGF.
- These macrophage-derived factors interact with or modulate the epidermal growth factor (EGF) signaling pathway in hepatocytes.
