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Cellular- and permeability-changes in the peritoneal cavity of mice after injection of endotoxon
Abstract:
Injection of endotoxin into the peritoneal cavity of mice causes an early emigration of PMN-leucocytes and therafter a decrease in macrophage count. The number of lymphocytes shows only a transient increase. One and 2 injections of endotoxin rise the fibrinogen and protein level of the peritoneal fluid. A simple test for measuring the change in permeability (and lymph circulation) was described ("congo red elimination's test"). Changes in permeability occur after a latent period of 2 hours following endotoxin administration, culminate during the 1st day and last about 3-4 days. The possible mechanisms of the above phenomena are discussed.
Insights
Endotoxin injection in mice rapidly alters peritoneal fluid by increasing polymorphonuclear leukocytes (PMN-leukocytes) and fibrinogen, while decreasing macrophages. Permeability changes occur within hours, peaking on day one.
Area of Science:
- Immunology
- Physiology
Background:
- Endotoxin administration triggers inflammatory responses in the peritoneal cavity.
- Understanding cellular and protein dynamics in peritoneal fluid is crucial for studying inflammation.
Purpose of the Study:
- To investigate the effects of endotoxin on peritoneal fluid composition and vascular permeability in mice.
- To characterize the temporal changes in cellular populations and protein levels post-endotoxin challenge.
Main Methods:
- Mice were injected with endotoxin into the peritoneal cavity.
- Polymorphonuclear leukocytes (PMN-leukocytes), macrophages, and lymphocytes were quantified.
- Fibrinogen and protein levels in peritoneal fluid were measured.
- Vascular permeability was assessed using the "congo red elimination's test".
Main Results:
- Early emigration of PMN-leukocytes and a subsequent decrease in macrophage count were observed.
- Lymphocyte numbers showed only a transient increase.
- One and two endotoxin injections elevated peritoneal fluid fibrinogen and protein levels.
- Vascular permeability increased after a 2-hour latent period, peaking on day 1 and lasting 3-4 days.
Conclusions:
- Endotoxin induces significant, time-dependent changes in peritoneal fluid cellularity and protein content.
- The study quantifies alterations in vascular permeability following endotoxin exposure.
- The findings provide insights into the mechanisms of endotoxin-induced peritoneal inflammation.