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Published on: February 22, 2019
Cytokine profiles, apoptosis and pathology of experimental Pasteurella multocida serotype A1 infection in mice
P Ezhil Praveena1, Sivakumar Periasamy, A A Kumar
1Division of Veterinary Pathology, Indian Veterinary Research Institute, Izatnagar 243 112, India.
Abstract:
Mice were experimentally infected with Pasteurella multocida serotype A1 to study the cytokine profiles, host cell apoptosis and sequential pathology at different hours of post-infection. Infected mice were dull, anorectic and depressed. A transient leukocytopenia followed by progressive leukocytosis was observed in the course of infection. Serum cytokine profiles showed significantly (P<0.01) higher amount of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6 and mouse KC) in the infected mice when compared to control mice. The circulating lymphocytes were apoptotic on annexin V staining. Apoptotic nuclei were detected in splenocytes, hepatocytes and infiltrating leukocytes of the lungs on TUNEL staining. The lungs were grossly congested and hemorrhagic, and showed infiltration with polymorphonuclear cells at early and mononuclear cells in the late hours of infection. Alveolar epithelia, inter-alveolar septa and capillary endothelium of the lungs showed ultrastructural changes. Liver had degenerative changes in histological and ultrathin sections.
Insights
Pasteurella multocida infection in mice causes inflammation and cell death. Pro-inflammatory cytokines increase, leading to apoptosis in lymphocytes, liver, and lung cells, indicating severe pathology.
Area of Science:
- Veterinary Pathology
- Immunology
- Microbiology
Background:
- Pasteurella multocida is a significant bacterial pathogen in animals.
- Understanding its pathogenic mechanisms is crucial for disease control.
Purpose of the Study:
- To investigate the cytokine profiles, host cell apoptosis, and sequential pathology following experimental Pasteurella multocida serotype A1 infection in mice.
Main Methods:
- Mice were infected with P. multocida A1.
- Serum cytokine levels (TNF-α, IL-1β, IL-6, KC) were measured.
- Apoptosis was assessed using Annexin V and TUNEL staining.
- Histopathological and ultrastructural changes in lungs and liver were examined.
Main Results:
- Infected mice exhibited clinical signs of illness, leukocytopenia followed by leukocytosis.
- Significant increases in pro-inflammatory cytokines were observed.
- Apoptosis was detected in circulating lymphocytes, splenocytes, hepatocytes, and lung-infiltrating leukocytes.
- Lungs showed congestion, hemorrhage, and cellular infiltration; liver exhibited degenerative changes.
Conclusions:
- P. multocida A1 infection induces a strong pro-inflammatory response and widespread host cell apoptosis.
- The observed pathological changes in the lungs and liver contribute to the disease severity.
