Mast cell degranulation in a novel fungus concentration-dependent rat model for acute invasive fungal rhinosinusitis

Abstract

Acute invasive fungal rhinosinusitis (AIFR) is a lethal disease afflicting immunocompromised individuals. Knowledge about this disease is limited due to the scarcity of AIFR animal models. Mast cells (MCs) are immune cells that participate in allergic and inflammatory conditions. Limited attention has been given to MCs in AIFR. Our objectives were to create a rat model of AIFR based on analyzing the impact of different fungal concentrations on establishing infection, and to examine the relationship between MCs and rat AIFR. Rats were divided randomly into four groups. The inoculated <i>Aspergillus fumigatus</i> concentration was 5 × 107 conidia/mL in group A, 107 conidia/mL in group B, and 106 conidia/mL in group C. Group D was the control set. Hematology and histopathology investigations were performed. An AIFR rat model was established successfully with an incidence rate of 90% in group A, 50% in group B and 10% in group C. The total number of MCs in the experimental groups was not significantly increased, but MCs degranulation was only found in infected nasal cavities. This investigation illustrates that various fungal concentrations have different effects on AIFR incidence, and MCs may play a role in the protection of sinuses against acute <i>A. fumigatus</i> infection.