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Combined effects of both bacteria and gastric juice on pneumonia in mice
1Department of Geriatric Medicine, Tohoku University School of Medicine, Sendai, Japan.
Abstract:
The effects of a combined inoculation of gastric juice and Streptococcus pneumoniae on the lungs of mice was investigated. Survival rates of mice inoculated with bacteria alone, gastric juice alone, and both bacteria and gastric juice were compared over 18 days. Xanthine oxidase (XO) activities in the lung tissues of mice inoculated with bacteria and gastric juice were measured and injected with a free radical scavenger, pyran-superoxide dismutase (pyran-SOD). A high mortality rate was observed in mice inoculated with both gastric juice and Streptococcus pneumoniae (81%). Mice inoculated with either Streptococcus pneumoniae or gastric juice showed a separate mortality rate of up to 10% during 18 days after inoculation. XO activity in the lung tissue of the mice inoculated with both gastric juice and bacteria was higher than in mice inoculated with either of them separately. The high mortality rate in the group inoculated with both two agents was reduced to 25% by the administration of pyran-SOD. XO activity raised by Streptococcus pneumoniae and gastric juice was significantly reduced by pyran-SOD. Thus, we suggest an important role in the combined effects of gastric juice and bacteria on pneumonia.
Insights
Combined gastric juice and Streptococcus pneumoniae significantly increased pneumonia mortality in mice. A free radical scavenger, pyran-superoxide dismutase (pyran-SOD), reduced mortality and xanthine oxidase activity, suggesting a role in pneumonia pathogenesis.
Area of Science:
- Microbiology
- Pathophysiology
- Toxicology
Background:
- Pneumonia is a significant global health concern.
- The role of gastric juice in bacterial lung infections is not fully understood.
- Streptococcus pneumoniae is a common cause of bacterial pneumonia.
Purpose of the Study:
- To investigate the synergistic effects of gastric juice and Streptococcus pneumoniae on mouse lung infections.
- To evaluate the impact of combined agents on mortality rates and lung tissue xanthine oxidase (XO) activity.
- To assess the efficacy of a free radical scavenger, pyran-superoxide dismutase (pyran-SOD), in mitigating these effects.
Main Methods:
- Mice were inoculated with Streptococcus pneumoniae, gastric juice, or both.
- Survival rates were monitored over 18 days.
- Xanthine oxidase (XO) activity in lung tissue was measured.
- Mice received pyran-superoxide dismutase (pyran-SOD) to assess its protective effects.
Main Results:
- Combined inoculation resulted in an 81% mortality rate, compared to 10% for individual inoculations.
- XO activity was significantly elevated in mice exposed to both agents.
- Administration of pyran-SOD reduced mortality to 25% and decreased XO activity.
- Pyran-SOD effectively counteracted the increase in XO activity induced by the combined agents.
Conclusions:
- Gastric juice potentiates the pathogenicity of Streptococcus pneumoniae, leading to increased pneumonia mortality.
- Xanthine oxidase (XO) activity plays a crucial role in the observed synergistic toxicity.
- Free radical scavenging with pyran-SOD demonstrates a potential therapeutic strategy against this combined insult.