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Updated: Sep 20, 2025
Evaluation of T Follicular Helper Cells and Germinal Center Response During Influenza A Virus Infection in Mice
Published on: June 27, 2020
Establishment and Evaluation of Fatigue Mice Model in the Convalescence Phase of Influenza A
Xiaoke Zeng1, Cheng Zhang1, Jianing Shi1
1College of Traditional Chinese Medicine, Hunan University of Chinese Medicine, Xueshi Road Campus, Changsha 410208, China.
Abstract:
Certain strains of Influenza A virus (IAV), a primary cause of influenza, can lead to pneumonia. Patients recovering from influenza pneumonia may experience physical discomfort akin to post-acute sequelae of COVID-19 (PASC). Despite extensive clinical research on viral pneumonia during convalescence, animal model studies are scarce, highlighting the need for a reliable model for pharmaceutical research. In this study, BALB/c mice were divided into three groups: NC (control), MC (infected with IAV), and Model (treated with oseltamivir post-infection for five days). A fatigue model was then induced in the Model group through diet restriction and weight-bearing swimming. The results showed the MC group had a 75% survival rate, while the NC and Model groups had 100%. Both the MC and Model groups experienced rapid weight loss followed by gradual recovery, differing significantly from the NC group. From dpi (days post-inoculation) 6 to dpi9, the MC group lost more weight than the NC group. The MC group had the highest pulmonary index, but there was no significant difference in IAV Nucleoprotein (NP) expression across groups. The Model group had higher IL-10 levels than the NC and MC groups, while the MC group had the highest TNF-α expression. Hematoxylin and eosin (H&E) staining revealed pathological changes in the MC and Model groups, with severe damage and pulmonary fibrosis in the MC group. Oxidative stress markers showed the MC group had the highest lactate dehydrogenase (LDH) and malondialdehyde (MDA) levels and lowest superoxide dismutase (SOD) activity. Electron microscopy indicated mitochondrial damage in both the MC and Model groups. The Model group had the lowest splenic and thymic indices, with histological findings showing larger splenic nodules in the MC group and poor thymocyte density and atrophy in the Model group. The successful creation of this mouse model of influenza pneumonia convalescence phase fatigue, exhibiting fatigue syndrome with various symptoms, holds significance for PASC and other viral pneumonia convalescence phase animal model research.
Insights
Researchers developed a mouse model for influenza pneumonia's fatigue phase, mimicking post-viral symptoms. This model aids pharmaceutical research into conditions like post-acute sequelae of COVID-19 (PASC).
Area of Science:
- Virology
- Immunology
- Pathology
Background:
- Influenza A virus (IAV) can cause pneumonia, with recovery symptoms resembling post-acute sequelae of COVID-19 (PASC).
- Limited animal models exist for studying viral pneumonia convalescence, hindering pharmaceutical research.
Purpose of the Study:
- To establish a reliable mouse model for the convalescence phase of influenza pneumonia, focusing on fatigue syndrome.
- To investigate the pathological and immunological changes during influenza pneumonia recovery.
Main Methods:
- BALB/c mice were infected with IAV and treated with oseltamivir.
- A fatigue model was induced via diet restriction and swimming.
- Survival rates, weight changes, pulmonary indices, immune markers (IL-10, TNF-α), tissue pathology (H&E), oxidative stress (LDH, MDA, SOD), and organ indices (spleen, thymus) were analyzed.
Main Results:
- The model group showed 100% survival, unlike the infected group (75%).
- Both infected and model groups exhibited weight loss and recovery patterns distinct from controls.
- Influenza pneumonia induced significant pulmonary damage, fibrosis, oxidative stress, mitochondrial dysfunction, and immune alterations.
Conclusions:
- A novel mouse model successfully replicates influenza pneumonia convalescence fatigue syndrome.
- This model is valuable for pharmaceutical research on PASC and other viral pneumonia recovery phases.
