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Tissue apoptosis in mice infected with Leptospira interrogans serovar Icterohaemorrhagiae
Márcia Marinho1, Cilene Vidovix Táparo1, Itamar S Oliveira-Júnior2
1Department of Support, Production and Animal Health, Veterinary Medicine School, São Paulo State University (UNESP - Univ Estadual Paulista), Araçatuba, São Paulo Brazil.
Background:
This investigation aimed to evaluate the occurrence of some apoptotic features induced by Leptospira interrogans serovar Icterohaemorrhagiae infection in young BALB/c mice during 2, 4, 7, 10, 14 and 21 days post-infection (dpi).
Methods:
The animals were euthanized and lung, liver and kidneys were harvested to histopathology analysis and immunohistochemistry to caspase-3 antigen detection was performed.
Results:
Chromatin condensation in kidney and liver tissues, but not in lung tissue, was observed. Caspase-3 reactive cells, mainly characterized as renal epithelial cells, were detected in the days 14 and 21 at high levels when compared to days 2, 4 and 7 (p = 0.025; p < 0.05). Lung sections revealed caspase-3 labeled alveolar cells in 10 and 14 days post-infection was higher than observed at 7 days (p = 0.0497; p < 0.05). Liver sections demonstrated reactive cells at a highest level at 14 and 21 days post-infection when comparison to 2, 4, 7 and 10 days (p = 0.0069; p < 0.05).
Conclusions:
Our results suggest that infection of L. interrogans induce in kidney, liver and lung an activation of apoptosis mediated by caspase-3 dependent pathway in later phases of infectious process.
Insights
Leptospira interrogans infection in mice triggers apoptosis in the kidneys and liver, indicated by caspase-3 activation. These apoptotic changes become more pronounced in later stages of the infection.
Area of Science:
- Pathology
- Microbiology
- Immunology
Background:
- Investigates apoptotic features induced by Leptospira interrogans serovar Icterohaemorrhagiae infection.
- Utilizes young BALB/c mice as a model system.
- Examines infection dynamics over 2, 4, 7, 10, 14, and 21 days post-infection (dpi).
Purpose of the Study:
- To evaluate the occurrence and characteristics of apoptosis in mice infected with Leptospira interrogans.
- To determine the role of caspase-3 in the apoptotic process during leptospirosis.
- To correlate apoptotic changes with the progression of infection in key organs.
Main Methods:
- Histopathological analysis of lung, liver, and kidney tissues.
- Immunohistochemistry for the detection of caspase-3 antigen.
- Euthanasia of infected mice at predetermined time points for tissue harvesting.
Main Results:
- Chromatin condensation observed in kidney and liver tissues, but not lung.
- Increased caspase-3 reactive cells (renal epithelial cells) noted at 14 and 21 dpi compared to earlier time points (p < 0.05).
- Elevated caspase-3 labeled alveolar cells in lung at 10 and 14 dpi, and in liver at 14 and 21 dpi (p < 0.05).
Conclusions:
- Leptospira interrogans infection activates apoptosis in the kidney, liver, and lung.
- The observed apoptosis is mediated by a caspase-3 dependent pathway.
- Apoptotic changes are prominent in the later phases of the infectious process.
