A novel fungus concentration-dependent rat model for acute invasive fungal rhinosinusitis: an experimental study
Yuyan Yan1, Zuotao Zhao2, Hongfei Wan3
1Department of Pathology, Affiliated Beijing Tongren Hospital, Capital Medical University, Beijing, 100730, People's Republic of China. yanyuyan20061979@126.com.
Background:
Acute invasive fungal rhinosinusitis is a lethal infectious process afflicting immunocompromised individuals. Knowledge about this disease is still limited due to the scarcity of animal models designed to study the pathogenesis of this infection. Mast cells are tissue-resident immune cells that participate in a variety of allergic and inflammatory conditions. Limited attention has been given to the role of mast cells in acute invasive fungal rhinosinusitis. Therefore, the objectives of this study were to create a rat model of acute invasive fungal rhinosinusitis based on analyzing the impact of different fungal concentrations on establishing infection, and to observe the changes of mast cells in rats with this disease.
Methods:
Sprague-Dawley rats were divided randomly into four groups, three of which were experimental and received different concentrations of Aspergillus fumigatus inoculations, and one was a control group (D). The inoculated Aspergillus fumigatus concentrations were 5 × 10(7) conidia/ml in group A, 10(7) conidia/ml in group B, and 10(6) conidia/ml in group C. Before fungal inoculation, rats were immunosuppressed using cyclophosphamide and cortisone acetate, and had Merocel sponges inserted into the right nares. Hematology and histopathology investigations were then performed.
Results:
An acute invasive fungal rhinosinusitis rat model was established successfully with an incidence rate of 90% in group A, 50% in group B and 10% in group C. Aspergillus fumigatus invasion was observed in 20% of the lungs in group A, but was not seen in the remaining groups. In addition, no fungi invaded the orbital tissue, brains, livers, spleens or kidneys of any rat. Compared with the control set, the total number of mast cells in the experimental groups was not significantly increased, but mast cell degranulation, on the other hand, was only found in infected nasal cavities.
Conclusions:
This investigation illustrates that various fungal concentrations have different effects on the incidence of acute invasive fungal rhinosinusitis, and it also demonstrates the feasibility of using this model to study the process of fungal rhinosinusoidal invasion. In addition, the results suggest that mast cells may play a role in the protection of sinuses against acute Aspergillus fumigatus infection and in the clearance of established hyphal masses.
Insights
This study developed a rat model for acute invasive fungal rhinosinusitis, finding that higher Aspergillus fumigatus concentrations increase infection rates. Mast cells in infected sinuses showed degranulation, suggesting a protective role against fungal invasion.
Area of Science:
- Mycology
- Immunology
- Pathogenesis
Background:
- Acute invasive fungal rhinosinusitis is a severe infection in immunocompromised individuals.
- Limited animal models exist for studying this disease's pathogenesis.
- The role of mast cells in fungal rhinosinusitis requires further investigation.
Purpose of the Study:
- To establish a rat model for acute invasive fungal rhinosinusitis.
- To analyze the impact of varying Aspergillus fumigatus concentrations on infection.
- To observe mast cell changes during fungal rhinosinusitis.
Main Methods:
- Sprague-Dawley rats were immunosuppressed and inoculated with different concentrations of Aspergillus fumigatus.
- A control group received no fungal inoculation.
- Hematology and histopathology were performed to assess infection and mast cell activity.
Main Results:
- A rat model of acute invasive fungal rhinosinusitis was successfully established.
- Infection incidence correlated with fungal concentration (90% at 5x10^7 conidia/ml).
- Mast cell degranulation occurred in infected nasal cavities, but total numbers did not significantly increase.
Conclusions:
- Fungal concentration significantly influences the incidence of acute invasive fungal rhinosinusitis.
- The developed rat model is suitable for studying fungal rhinosinusoidal invasion.
- Mast cells may protect sinuses against Aspergillus fumigatus and aid in clearing fungal masses.
