Abstract: Objective To investigate the effects of prophylactic administration of Shufeng Jiedu capsules on mice withinfluenza A virus pneumonia and the possible mechanisms of intervention. Methods Influenza A (H1N1) virus (FM1 strain) was used to infect ICR mice with nasal drops to construct a viral pneumonia model. The general status of mice in each group was observed at a fixed time every day, and the lung index, inhibition rate, and viral load of mice in each group were calculated; Micro-CT and hematoxylin-eosin staining (HE) were used to observe histomorphological changes in mouse lungs; An enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of tumor necrosis factor (TNF-α) and interleukin-6 (IL-6) in lung tissues; protein immunoblotting (Western blot) was used to detect the expression levels of TLR4 and MyD88 proteins in lung tissues. Results Prophylactic administration of Shufeng Jiedu capsules reduced lung index, decreased viral load in lung tissue, repaired lung damage, attenuated lung lesions and decreased TNF-α and IL-6 levels in lung tissues in mice with influenza. Western blot results showed that Shufeng Jiedu capsules could down-regulatethe expression of TLR4 and MyD88 proteins in lung tissue. Conclusion Prophylactic administration of Shufeng Jieducapsules had a protective effect in mice with influenza A virus pneumonia. The mechanism is related to the inhibition of viral replication, improvement of lung tissue lesions, inhibition of inflammatory factor release and down-regulation of TLR4 and MyD88 protein expression in lung tissue.

Key words: influenza A virus, Shufeng Jiedu capsules, anti-viral effect, TLR4/MyD88, mice, lung tissue, pneumonia