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Histopathological lesions produced by P. aeruginosa lipopolysaccharide in rats
G N Tzanakakis1, D K Veronikis, E D Anastasiou
1Department of Surgery, Brown University, Providence, RI.
Abstract:
The lipopolysaccharide (LPS) of Pseudomonas aeruginosa is considered to be less toxic than the LPS from the Enterobacteriaceae family. The present study was undertaken to determine the time course of lesions produced in the lungs, spleen, liver, kidneys and bone marrow from 1 to 168 hours following a single (1.5mg) intravenous injection of P. aeruginosa LPS--1R (S-form), and its mutant strains, 557 (R-form) and 605 (more-R-form)--in rats. The lesions consisted of atelectasis, infiltration by polymorphonuclear leukocytes, intraalveolar hemorrhage and perivascular edema of the lung, hyperplasia of the white pulp of the spleen, necrosis of hepatic parenchyma, vacuolization of cells of the adrenal zone fasciculata, and hyperplasia of bone marrow. Immunoperoxidase stain for the R-form and the more-R forms of LPS of P. aeruginosa showed similar distribution kinetics within hepatocytes and Kupffer cells, while the S-form required 24 hours to become evident within hepatocytes. The data show that all 3 LPS preparations are toxic, distributed differently within hepatocytes, as demonstrated by immunoperoxidase stains, and exhibit different time courses and severity of lesions within the affected organs.
Insights
Pseudomonas aeruginosa lipopolysaccharide (LPS) exhibits toxicity and distinct organ lesion patterns in rats. Different LPS forms show varied distribution in liver cells, impacting toxicity and lesion development over time.
Area of Science:
- Microbiology
- Toxicology
- Pathology
Background:
- Lipopolysaccharide (LPS) from Pseudomonas aeruginosa is generally considered less toxic than Enterobacteriaceae LPS.
- Understanding the toxicological profile and organ distribution of P. aeruginosa LPS is crucial for assessing its pathogenicity.
Purpose of the Study:
- To investigate the time course and nature of organ lesions induced by different forms of P. aeruginosa LPS in rats.
- To compare the distribution kinetics of S-form, R-form, and more-R-form P. aeruginosa LPS within rat hepatocytes and Kupffer cells.
Main Methods:
- Single intravenous injection of P. aeruginosa LPS (S-form, R-form, more-R-form) in rats.
- Histopathological examination of lungs, spleen, liver, kidneys, and bone marrow from 1 to 168 hours post-injection.
- Immunoperoxidase staining to track LPS distribution in liver cells.
Main Results:
- All three LPS preparations induced significant lesions, including lung atelectasis and edema, splenic white pulp hyperplasia, hepatic necrosis, and bone marrow hyperplasia.
- R-form and more-R-form LPS showed rapid distribution in hepatocytes and Kupffer cells, while S-form LPS uptake was delayed.
- Distinct time courses and severity of organ lesions were observed for each LPS type.
Conclusions:
- P. aeruginosa LPS, in its various forms, is toxic to rats, inducing characteristic organ damage.
- The differential distribution kinetics of LPS forms within hepatocytes influence their toxic effects and lesion development.
- The study highlights the complex toxicological profile and organ-specific pathology of P. aeruginosa LPS.