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Increase of bovine alveolar macrophage superoxide anion and hydrogen peroxide release by dusts of different origin
I Berg1, T Schlüter, G Gercken
1Department of Biochemistry and Molecular Biology, University of Hamburg, Federal Republic of Germany.
Abstract:
The release of reactive oxygen intermediates (ROI) from bovine alveolar macrophages (BAM) after stimulation with heavy metal-containing dusts was investigated. BAM were obtained by postmortem lavages of bovine lungs. The dusts were collected from waste incineration, sewage sludge incineration, an electric power station, and from two different factories. Three quartz dusts were used as heavy metal-free controls. The dusts were fractionated by sieving and sedimentation and analyzed by electron microscopy, atomic absorption spectrometry (AAS), and atomic emission spectrometry with inductively coupled plasma (AES-ICP). Incubation of BAM with the dusts (12.5-1000 micrograms/ml medium) led to concentration-dependent increases in ROI release. The secretion of ROI was already seen after 15 min and lasted throughout the experiment up to 90 min, with the exception of a waste incinerator ash, which contained the highest contents of some heavy metals and where the release of ROI ceased after 60 min. We suggest that this dust exhibits simultaneously stimulating and inhibiting effects. The ratio of the secreted O2- and H2O2 varied, depending on the dust being investigated. The release of hydrogen peroxide correlated best, in descending order, with the content of iron, manganese, chromium, vanadium, and arsenic in the dusts.
Insights
Heavy metal dusts stimulate bovine alveolar macrophages (BAM) to release reactive oxygen intermediates (ROI). Specific metal content, like iron and manganese, influences hydrogen peroxide release, indicating varying dust toxicity.
Area of Science:
- Environmental Toxicology
- Cellular Biology
- Occupational Health
Background:
- Bovine alveolar macrophages (BAM) are crucial immune cells in lung defense.
- Industrial dusts can contain heavy metals, posing potential health risks.
- Reactive oxygen intermediates (ROI) are signaling molecules involved in cellular responses and inflammation.
Purpose of the Study:
- To investigate the release of ROI from BAM stimulated by heavy metal-containing dusts.
- To analyze the relationship between dust composition and ROI secretion.
- To assess the potential of different industrial dusts to induce oxidative stress in macrophages.
Main Methods:
- BAM were isolated from bovine lungs via postmortem lavage.
- Dust samples from various industrial sources were characterized (sieving, electron microscopy, AAS, AES-ICP).
- BAM were incubated with dusts at varying concentrations, and ROI release (O2-, H2O2) was measured over time.
Main Results:
- Dust exposure led to a concentration-dependent increase in ROI release from BAM.
- ROI secretion was observed within 15 minutes and persisted up to 90 minutes for most dusts.
- One waste incinerator ash, high in heavy metals, showed a transient ROI release, suggesting dual effects.
- Hydrogen peroxide release correlated with iron, manganese, chromium, vanadium, and arsenic content.
Conclusions:
- Heavy metal-containing industrial dusts can induce significant ROI release from bovine alveolar macrophages.
- The specific heavy metal composition of dusts influences the type and magnitude of ROI response.
- Certain dusts may exhibit complex biological effects, including both stimulation and inhibition of cellular responses.