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Updated: Apr 8, 2026
Detecting Migration and Infiltration of Neutrophils in Mice
Published on: February 6, 2020
Neutrophilic infiltration in lungs of mice with peritonitis in acid or basic medium
Bruno F Muniz1, Gabriel M Netto1, Moacir Jr Ferreira1
1Laboratory of Experimental Surgery (Medical School) and Laboratory of Protozoosis (Institute of Biological Sciences), Universidade Federal de Minas Gerais Belo Horizonte, Minas Gerais, Brasil (Brazil).
Background:
Bacterial peritonitis is associated with systemic complications such as pneumonia.
Objective:
To determine in an experimental model of peritonitis whether the pH of peritoneal fluid infection influences the influx of neutrophils into the lung, and whether treatment outcome would be similar in peritonitis with liquid at any pH.
Materials And Methods:
We studied 48 mice with peritonitis induced by cecal ligation and puncture. The animals were distributed randomly into three groups: the first one had an injection into the peritoneal cavity with saline, pH 7.0; the second group was injected with saline, pH 8.0; and the third group with saline, pH 3.0. After 2 hours, half the animals in each group was treated by washing the abdominal cavity with warm saline solution and administration of ceftriaxone every 12 hours, and half of each group was killed by anesthetic overdose, and lung biopsy was done. The animals kept in treatment were killed 24 hours after treatment, and lung biopsy was also performed. The samples were stained with H&E and the number of neutrophils in 20 areas was checked. The mean number of cells in each group was compared between groups and with an untreated one.
Results:
The group with peritonitis associated with alkaline solution showed a higher population of neutrophils during untreated peritonitis (P = 0.04). The response to treatment by lavage of the peritoneal cavity and antibiotics was more effective in reducing the population of neutrophils in the group with peritonitis at pH 8.0, unlike that observed in animals with peritonitis at pH 3.0 (P = 0.03).
Conclusion:
Peritonitis associated with lower pH solution, despite the lower influx of leukocytes in the first two hours after installation of peritonitis, was not able to reduce the population of these cells in mice's lung in response to standard therapy.
Insights
Peritonitis pH impacts neutrophil lung influx. Alkaline peritonitis (pH 8.0) responded better to treatment than acidic (pH 3.0), suggesting pH influences treatment efficacy in bacterial peritonitis.
Area of Science:
- Experimental pathology
- Microbiology
- Immunology
Background:
- Bacterial peritonitis can lead to systemic complications, including pneumonia.
- Understanding factors influencing peritonitis progression is crucial for effective treatment.
Purpose of the Study:
- To investigate the influence of peritoneal fluid pH on neutrophil migration to the lungs in an experimental peritonitis model.
- To evaluate if treatment outcomes for peritonitis vary based on peritoneal fluid pH.
Main Methods:
- A mouse model of peritonitis was established using cecal ligation and puncture.
- Animals were assigned to groups receiving peritoneal saline injections at pH 7.0, 8.0, or 3.0.
- Neutrophil counts in lung biopsies were assessed after 2 hours and 24 hours post-treatment with lavage and antibiotics (ceftriaxone).
Main Results:
- Untreated peritonitis with alkaline fluid (pH 8.0) showed a significantly higher neutrophil population in the lungs compared to other groups (P = 0.04).
- Treatment involving peritoneal lavage and antibiotics was more effective in reducing lung neutrophils in the pH 8.0 peritonitis group compared to the pH 3.0 group (P = 0.03).
Conclusions:
- Peritoneal fluid pH significantly affects neutrophil influx into the lungs during experimental peritonitis.
- Acidic peritonitis (pH 3.0) demonstrated a lower initial neutrophil influx but was less responsive to standard therapy compared to alkaline peritonitis (pH 8.0).
