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Methods for Detecting Cough and Airway Inflammation in Mice
Published on: August 2, 2024
Pathological examination of lung tissues in influenza a virus-infected mice
Nilton Akio Muto1, Yuji Sunden, Tomoe Hattori
1Division of Molecular Pathobiology, Research Center for Zoonosis Control, Hokkaido University, Sapporo, Japan.
Abstract:
This study examined pathological changes in the lung tissues of young and aged mice infected with influenza virus. Young mice inoculated with influenza virus showed body weight loss at 4 days post-infection (dpi), meanwhile body weight decrease started from 9 dpi in the aged mice. We histopathologically examined the lungs of these mice. Immunohistochemical examination revealed that viral antigen-positive bronchiolar and alveolar epithelial cell numbers at 3 dpi were significantly higher in young mice than in the aged ones. Further, viral antigen-positive cells were observed at 9 dpi in the aged mice, but not in the young ones. Diffuse and severe bronchointerstitial pneumonia characterized by the accumulation of polymorphonuclear leukocytes (PMNs) was observed in young mice at 6 dpi. Histopathological changes in the aged mice were milder than those in the young mice. Moreover, T cell and macrophage accumulation in the lungs was significantly higher in the young mice than in the aged mice at 9 dpi. These results suggest that there may be a correlation between the relatively low level of infiltration of PMNs, macrophages, and T lymphocytes and the delayed body weight loss and longer lasting infections observed in the lungs of the aged mice. These findings provide detailed insights into the age-specific course of infection in young and aged populations with associated differences in lung pathology.
Insights
Aged mice infected with influenza virus exhibit delayed body weight loss and milder lung pathology compared to young mice. This is linked to lower immune cell infiltration, suggesting age-specific differences in viral infection response.
Area of Science:
- Immunology
- Pathology
- Virology
Background:
- Influenza virus infection impacts different age groups variably.
- Understanding age-related differences in host response is crucial for managing viral infections.
Purpose of the Study:
- To compare the pathological changes and immune responses in the lungs of young and aged mice infected with influenza virus.
- To investigate the correlation between immune cell infiltration and disease progression in different age groups.
Main Methods:
- Histopathological examination of lung tissues.
- Immunohistochemical analysis to detect viral antigens and immune cell infiltration (T cells, macrophages, polymorphonuclear leukocytes - PMNs).
- Monitoring of body weight changes post-infection.
Main Results:
- Young mice showed earlier body weight loss and higher viral antigen-positive cells at 3 days post-infection (dpi) compared to aged mice.
- Aged mice exhibited delayed onset of body weight loss (9 dpi) and prolonged presence of viral antigens.
- Young mice displayed more severe bronchointerstitial pneumonia with significant infiltration of PMNs, T cells, and macrophages at 6-9 dpi, while aged mice showed milder pathology and lower immune cell accumulation.
Conclusions:
- Aged mice demonstrate a delayed and less severe response to influenza virus infection, characterized by reduced immune cell infiltration.
- Lower levels of PMNs, macrophages, and T lymphocytes in aged mice correlate with delayed weight loss and persistent infection.
- These findings highlight significant age-specific differences in lung pathology and immune response during influenza virus infection.
