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The response of isolated rabbit hepatic macrophages (H-M macrophage) to lipopolysaccharide (LPS)
Abstract:
In order to evaluate the possible role of the hepatic macrophage (H-M macrophage) in lipopolysaccharide-induced shock and disseminated intravascular coagulation (DIC), a technique has been developed for the isolation and maintenance in culture of rabbit H-M macrophage. Characterization of the resultant cell population by morphology, nonspecific esterase staining, phagocytosis of latex beads, by presence of Fc and C3b membrane receptors confirms a pure population of M macrophage without outgrowth of other cell types for up to 10 days in culture. The exposure in vitro of the H-M macrophage to LPS (either Salmonella minnesota R595 or Escherichia coli 0111:B4) stimulates a selective increase in activity of several cellular enzyme: LDH, lysozyme, plasminogen activator, and a procoagulant factor, with minimal changes in acid phosphatase and beta-glucuronidase detected. Concomitantly, both in vivo and in vitro treatment with LPS produces an apparent direct cellular toxicity. The combined effect of toxicity and selective stimulation and release of mediators in LPS-stimulated H-M macrophage may play a central role in the endotoxemic shock syndrome.
Insights
Hepatic macrophages (H-M macrophages) play a key role in lipopolysaccharide-induced shock and disseminated intravascular coagulation (DIC). LPS stimulation increases H-M macrophage enzyme activity and causes toxicity, contributing to endotoxemic shock.
Area of Science:
- Immunology
- Cell Biology
- Pathophysiology
Background:
- Hepatic macrophages (H-M macrophages) are crucial immune cells in the liver.
- Lipopolysaccharide (LPS) is a potent endotoxin that can trigger severe inflammatory responses.
- Disseminated intravascular coagulation (DIC) is a life-threatening condition involving widespread blood clotting.
Purpose of the Study:
- To investigate the role of H-M macrophages in LPS-induced shock and DIC.
- To develop a method for isolating and culturing rabbit H-M macrophages for in vitro studies.
Main Methods:
- Isolated and cultured rabbit H-M macrophages, confirming purity via morphology, esterase staining, phagocytosis, and receptor presence.
- Exposed H-M macrophages in vitro to LPS from Salmonella minnesota R595 and Escherichia coli 0111:B4.
- Assessed cellular enzyme activity (LDH, lysozyme, plasminogen activator, procoagulant factor) and cellular toxicity post-LPS exposure.
Main Results:
- A pure H-M macrophage population was maintained in culture for up to 10 days.
- LPS stimulation selectively increased LDH, lysozyme, plasminogen activator, and procoagulant factor activity in H-M macrophages.
- LPS exposure induced direct cellular toxicity in H-M macrophages both in vivo and in vitro.
Conclusions:
- The combined effects of LPS-induced H-M macrophage toxicity and mediator release are implicated in endotoxemic shock.
- H-M macrophages are central players in the pathophysiology of LPS-induced shock and DIC.