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The pathogenesis of Chlamydia pneumoniae-type pneumonitis in mice
1Department of Respiratory Medicine, Nanjing Jinling Hospital, Medical College of Nanjing University, Nanjing 210002, China. shichen@jlonline.com
Objective:
To evaluate mice as experimental animals for Chlamydia pneumoniae (C. pneumoniae) infection and investigate the pathogenesis of C. pneumoniae derived pneumonitis.
Methods:
Icr mice were inoculated with the C. pneumoniae strain, CWL-029, either intranasally or intravenously. After a single dose inoculation, mice were killed on the 1st, 3rd, 7th, 14th, 21st, 28th and 60th days. The pathological changes in lung tissue were analyzed.
Results:
The Icr mice were shown to be susceptible to C. pneumoniae. Inoculation into mice with C. pneumoniae induced a prolonged course of lung infection, as demonstrated by persistence of lung pathology (up to 60 days). Via intranasal inoculation of mice, lung pathology was characterized by patchy interstitial pneumonitis with predominantly neutrophil leukocyte infiltration early (within the first 7 days) and lymphocyte infiltration in the later stages (14 days later) of infection. After intravenous inoculation, a similarly developed interstitial pneumonitis was observed, but it was milder and patchier, especially in early stages. C. pneumoniae DNA was detected by polymerase chain reaction (PCR) intermittently in the lung tissue. Inoculated mice developed serum IgG antibody responses.
Conclusion:
The Icr mice were susceptible to C. pneumoniae, resulting in a pulmonary infection characterized by interstitial pneumonitis, occurring most strongly via intranasal inoculation.
Insights
Mice are susceptible to Chlamydia pneumoniae (C. pneumoniae) infection, developing prolonged lung inflammation. Intranasal inoculation causes more severe interstitial pneumonitis than intravenous routes.
Area of Science:
- * Infectious Diseases
- * Pulmonology
- * Animal Models
Background:
- * Chlamydia pneumoniae (C. pneumoniae) is a significant respiratory pathogen.
- * Understanding its pathogenesis requires suitable animal models.
Purpose of the Study:
- * To assess the utility of Icr mice for modeling C. pneumoniae infection.
- * To investigate the pathological mechanisms of C. pneumoniae-induced pneumonitis.
Main Methods:
- * Icr mice were intranasally or intravenously inoculated with C. pneumoniae strain CWL-029.
- * Lung tissues were analyzed for pathological changes at multiple time points (days 1-60).
- * C. pneumoniae DNA detection via PCR and serum antibody responses were assessed.
Main Results:
- * Icr mice exhibited susceptibility to C. pneumoniae, with persistent lung pathology up to 60 days.
- * Intranasal inoculation led to patchy interstitial pneumonitis with neutrophil and lymphocyte infiltration.
- * Intravenous inoculation resulted in milder, patchier pneumonitis; C. pneumoniae DNA was intermittently detected.
Conclusions:
- * Icr mice serve as a viable model for studying C. pneumoniae pulmonary infections.
- * Intranasal inoculation is a more effective route for inducing C. pneumoniae-induced interstitial pneumonitis in mice.