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Published on: May 21, 2018
Bacteroides fragilis induce necrosis on mice peritoneal macrophages: In vitro and in vivo assays
J M B D Vieira1, S H Seabra, D C Vallim
1Laboratório de Tecnologia em Cultura de Células, UEZO, Rio de Janeiro, Brazil. jmanya@terra.com.br
Abstract:
Bacteroides fragilis is an anaerobic bacteria component of human intestinal microbiota and agent of infections. In the host B. fragilis interacts with macrophages, which produces toxic radicals like NO. The interaction of activated mice peritoneal macrophages with four strains of B. fragilis was evaluated on this study. Previously was shown that such strains could cause metabolic and morphologic alterations related to macrophage death. In this work propidium iodide staining showed the strains inducing macrophage necrosis in that the labeling was evident. Besides nitroblue tetrazolium test showed that B. fragilis stimulates macrophage to produce oxygen radicals. In vivo assays performed in BalbC mice have results similar to those for in vitro tests as well as scanning electron microscopy, which showed the same surface pore-like structures observed in vitro before. The results revealed that B. fragilis strains studied lead to macrophage death by a process similar to necrosis.
Insights
Bacteroides fragilis, a gut bacteria, triggers macrophage death through necrosis. This study shows these bacteria stimulate macrophages to produce toxic oxygen radicals, leading to cell damage.
Area of Science:
- Microbiology
- Immunology
- Cell Biology
Background:
- Bacteroides fragilis is an anaerobic intestinal bacterium and a cause of infections.
- B. fragilis interacts with host macrophages, which produce nitric oxide (NO).
- Previous studies indicated B. fragilis strains cause metabolic and morphologic alterations leading to macrophage death.
Purpose of the Study:
- To evaluate the interaction of activated mice peritoneal macrophages with four strains of B. fragilis.
- To investigate the mechanism of macrophage death induced by B. fragilis.
Main Methods:
- Propidium iodide staining to detect necrosis.
- Nitroblue tetrazolium test to assess radical production.
- In vivo assays in BalbC mice.
- Scanning electron microscopy.
Main Results:
- Propidium iodide staining confirmed B. fragilis strains induce macrophage necrosis.
- Nitroblue tetrazolium test indicated B. fragilis stimulates macrophages to produce oxygen radicals.
- In vivo and in vitro findings were consistent, with scanning electron microscopy showing pore-like structures on macrophage surfaces.
Conclusions:
- The studied B. fragilis strains induce macrophage death via a necrosis-like process.
- B. fragilis interaction with macrophages involves the production of toxic oxygen radicals.
- The findings provide insights into the pathogenic mechanisms of B. fragilis infections.
