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ACUTE VASCULAR LESIONS IN MICE FOLLOWING INJECTIONS OF PNEUMOCOCCI
1Pathological Laboratory and Medical Clinic of Johns Hopkins University, Baltimore.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Pneumococci injections in mice cause toxic degeneration of blood vessel walls, leading to fatal intrathoracic hemorrhages. This occurs even with dead bacteria, suggesting a poison-induced vascular injury.
Area of Science:
- Pathology
- Toxicology
- Vascular Biology
Background:
- Intrathoracic hemorrhages are observed in mice post-pneumococci inoculation.
- The precise mechanism of hemorrhage in these cases requires elucidation.
Purpose of the Study:
- To investigate the cause of large intrathoracic hemorrhages in mice following pneumococci inoculation.
- To determine the pathological changes in thoracic organs and blood vessels.
Main Methods:
- Histological examination of thoracic organs from mice inoculated with live and dead pneumococci.
- Autopsy and microbiological cultures to identify causative agents and inflammatory responses.
Main Results:
- Acute, localized degeneration of large vessel walls (aorta, pulmonary arteries) was observed.
- Hemorrhage resulted from the tearing of degenerated vessel walls due to blood pressure.
- Lesions were linked to pneumococci inoculation, irrespective of bacterial viability, and lacked inflammatory signs.
Conclusions:
- Pneumococci-derived toxins likely cause acute degeneration of vessel walls.
- This toxic vascular injury is the primary cause of observed intrathoracic hemorrhages in mice.
- The findings highlight a non-inflammatory, toxin-mediated vascular pathology induced by pneumococci.
