Anti-inflammatory effects of Boletus edulis polysaccharide on asthma pathology

Asthma is a chronic airway disease common around the world. The burden of this disease could be reduced with new and effective treatments. Here, the efficacy of a polysaccharide extract from the Boletus edulis (BEP) mushroom, which has demonstrated anti-inflammatory properties, was tested in a mouse model of asthma. Five groups of BaLB/C mice were developed; one group served as a control and did not have asthma induction. The other four groups of mice were sensitized by ovalbumin challenge. FinePointe™ RC animal airway resistance and pulmonary compliance was used to assess airway function in asthma models. Three of the 4 model groups received treatments: one received pravastatin, one received dexamethasone, and one received BEP. Histopathology of lung tissues was performed using H&E and AB-PAS staining. Levels of cytokines IL-4 and IFN-g were detected using ELISA, qRT-PCR, and Western blotting. Cyclophilin A was measured by Western blot, and flow cytometry was used to determine the proportion of CD4⁺CD25⁺FOXP3⁺ Treg cells. BEP treatment resulted in improvements in lung pathology, IL-4 level (P<0.05), and IFN-γ level (P<0.05) similar to traditional dexamethasone treatment. Further, the proportion of anti-inflammatory CD4⁺CD25⁺FOXP3⁺ Treg cells significantly increased (P<0.05) compared to untreated asthma models, and expression of cyclophilin A significantly decreased (P<0.05). Thus, Boletus edulis polysaccharide reduces pro-inflammatory responses and increases anti-inflammatory responses in mouse models of asthma, suggesting this may be a novel treatment method.