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Neutrophil migration induced by inflammatory stimuli is reduced by macrophage depletion
G E Souza1, F Q Cunha, R Mello
1Department of Pharmacology, Faculty of Pharmaceutical Sciences, University of São Paulo, Brazil.
Abstract:
Previous experiments of our group have shown that neutrophil migration induced by inflammatory stimuli is reduced by agents which block the release from macrophages of a specific factor for neutrophil migration (MNCF, [1, 2]). The present paper evaluated the influence of macrophage depletion induced by lavage of the peritoneal cavity on neutrophil migration. In both normal and thioglycollate-stimulated peritoneal cavities, lavage with saline reduced the resident macrophage population by about 80% and significantly blocked neutrophil migration induced by inflammatory stimuli such as carrageenin, zymosan and E. coli endotoxin. Peritoneal lavage, however, did not affect neutrophil migration induced by MNCF. Thus, these results support the suggestion that macrophages participate in the control of neutrophil migration induced by acute inflammatory stimuli.
Insights
Macrophages are crucial for controlling neutrophil migration during acute inflammation. Depleting macrophages significantly blocks inflammatory cell movement, highlighting their essential role in the immune response.
Area of Science:
- Immunology
- Cell Biology
Background:
- Neutrophil migration is vital for acute inflammatory responses.
- Macrophages release a specific factor for neutrophil migration (MNCF).
- Previous studies indicated agents blocking MNCF release reduce neutrophil migration.
Purpose of the Study:
- To evaluate the influence of macrophage depletion on neutrophil migration.
- To determine the role of macrophages in mediating neutrophil recruitment during acute inflammation.
Main Methods:
- Peritoneal lavage was used to deplete resident macrophages.
- Neutrophil migration was assessed in normal and thioglycollate-stimulated peritoneal cavities.
- Migration was induced by inflammatory stimuli (carrageenin, zymosan, E. coli endotoxin) and MNCF.
Main Results:
- Peritoneal lavage reduced the macrophage population by approximately 80%.
- Macrophage depletion significantly blocked neutrophil migration induced by inflammatory stimuli.
- Neutrophil migration induced by MNCF was not affected by macrophage depletion.
Conclusions:
- Macrophages play a significant role in controlling neutrophil migration during acute inflammatory responses.
- The findings support the hypothesis that macrophages are essential mediators of inflammatory cell recruitment.