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Production of hydrogen peroxide by alveolar macrophages. Effect of barbiturates
J Wilhelm1, J Sojková, J Herget
1Department of Medical Chemistry and Biochemistry, Second Faculty of Medicine, Charles University, Prague, Czech Republic.
Abstract:
Production of hydrogen peroxide by rat lung alveolar macrophages represents one of the key events in the inflammatory process. For the interpretation of the in vitro measurements it is important to control all possible interfering influences. The present work documents that the type of anaesthesia might critically influence the observed results. H2O2 production was measured in isolated rat alveolar macrophages by luminol chemiluminescence catalyzed by horseradish peroxidase. Three different mechanisms of H2O2 production were observed after stimulation of cells with a chemotactic peptide (FMLP), phorbol ester (PMA), and during cell adherence. All these activities were influenced independently by the treatment with barbiturates, which both stimulated or inhibited the H2O2 production, depending on the barbiturate concentration. As the effective barbiturate concentrations were found to be within the range used for the anaesthesia of experimental animals, the presented results imply that barbiturates are not suitable for experiments in which the production of reactive oxygen species by phagocytes is measured, and that other anaesthetics should be tested.
Insights
Anesthesia type critically impacts hydrogen peroxide (H2O2) production measurements in rat macrophages. Barbiturates, commonly used for anesthesia, interfere with reactive oxygen species assays, necessitating alternative anesthetic choices for accurate results.
Area of Science:
- Immunology
- Cellular Biology
- Pharmacology
Background:
- Hydrogen peroxide (H2O2) production by alveolar macrophages is crucial in inflammation.
- Accurate in vitro measurement requires controlling confounding factors.
- Anesthetic agents can potentially interfere with cellular assays.
Purpose of the Study:
- To investigate the influence of anesthesia on H2O2 production in rat alveolar macrophages.
- To determine if barbiturates affect H2O2 generation by phagocytes.
- To assess the suitability of barbiturates for reactive oxygen species experiments.
Main Methods:
- Isolated rat lung alveolar macrophages were used.
- Luminol chemiluminescence catalyzed by horseradish peroxidase measured H2O2 production.
- Cells were stimulated with FMLP, PMA, and assessed during adherence.
- Effects of varying barbiturate concentrations were evaluated.
Main Results:
- Barbiturates significantly influenced H2O2 production, acting as either stimulators or inhibitors.
- Observed effects were concentration-dependent.
- Interference occurred across different H2O2 production pathways (FMLP, PMA, adherence).
Conclusions:
- Barbiturate anesthesia can critically alter H2O2 production measurements in macrophages.
- Effective barbiturate concentrations overlap with those used in animal anesthesia.
- Barbiturates are unsuitable for experiments measuring phagocyte reactive oxygen species; alternative anesthetics should be considered.