Related Experiment Videos
Comparison of blood and peritoneal neutrophil activity in rabbits with and without peritonitis
Abstract:
The neutrophil (polymorphonuclear cell, or PMN) function is an essential component of the host defense against infection. However, infection itself may alter PMN activity. To investigate both the effects of infection on PMN activity and PMN activity on survival, we evaluated control and infected blood and peritoneal PMN phagocytosis, chemotaxis, and superoxide anion production in rabbits with and without peritonitis. Control blood and peritoneal PMNs were obtained from noninfected rabbits which were subjected to intraperitoneal infusion of sterile hypertonic saline. Infected blood and peritoneal PMNs were obtained from rabbits which had undergone appendiceal devascularization and ligation 18 hr earlier. Phagocytosis was similar in all groups except for a threefold increase in normal peritoneal PMNs. Chemotaxis was inhibited by infection in the blood and peritoneal PMNs. Normal peritoneal PMNs also had decreased chemotaxis. Superoxide anion production was comparable in the infected and control blood; however, both control and infected peritoneal PMNs had elevated superoxide anion production. Of the infected rabbits, four died in 5 days or less. Of the six that lived, two developed intraabdominal abscesses. Blood and peritoneal PMN activity was similar in all rabbits despite their outcome. We conclude that (1) blood and peritoneal PMNs have different basal activities and responses to infection; (2) the milieu of the peritoneal cavity appears to alter the PMNs present; and (3) PMN activity did not predict morbidity or mortality.
Insights
Infection alters neutrophil (polymorphonuclear cell, or PMN) function, with distinct effects on blood and peritoneal PMNs. However, PMN activity did not predict survival or complications in infected rabbits.
Area of Science:
- Immunology
- Infectious Disease
Background:
- Neutrophil (polymorphonuclear cell, or PMN) function is critical for host defense against infection.
- Infections can significantly alter PMN activity, potentially impacting host outcomes.
- Understanding these alterations is crucial for managing infectious diseases.
Purpose of the Study:
- To investigate the effects of infection on neutrophil (PMN) activity.
- To examine the relationship between PMN activity and survival in an infection model.
- To compare the behavior of blood versus peritoneal neutrophils.
Main Methods:
- Evaluated phagocytosis, chemotaxis, and superoxide anion production in control and infected rabbits with peritonitis.
- Isolated blood and peritoneal neutrophils from rabbits subjected to sterile saline infusion or appendiceal devascularization.
- Compared PMN functions across different groups and correlated with rabbit survival and morbidity.
Main Results:
- Normal peritoneal neutrophils showed a threefold increase in phagocytosis compared to other groups.
- Infection inhibited chemotaxis in both blood and peritoneal neutrophils; normal peritoneal neutrophils also had reduced chemotaxis.
- Superoxide anion production was elevated in both control and infected peritoneal neutrophils, but comparable in blood neutrophils.
- PMN activity was similar in rabbits regardless of their outcome (death, survival, or abscess formation).
Conclusions:
- Blood and peritoneal neutrophils exhibit distinct basal activities and responses to infection.
- The peritoneal environment modifies the characteristics of resident neutrophils.
- Neutrophil (PMN) activity levels did not serve as a reliable predictor of morbidity or mortality in this rabbit peritonitis model.