Qiangzhi Decoction (羌跖汤) protects mice from influenza A pneumonia through inhibition of inflammatory cytokine storm

OBJECTIVE: To investigate the preventive effects of Qiangzhi Decoction (羌跖汤, QZD) on influenza A pneumonia through inhibition of inflammatory cytokine storm in vivo and in vitro. METHODS: One hundred ICR mice were randomly divided into the virus control, the Tamiflu control and the QZD high-, medium-, and low-dose groups. Mice were infected intranasally with influenza virus (H1N1) at 10 median lethal dose (LD(50)). QZD and Tamiflu were administered intragastrically twice daily from day 0 to day 7 after infection. The virus control group was treated with distilled water alone under the same condition. The number of surviving mice was recorded daily for 14 days after viral infection. The histological damage and viral replication and the expression of inflammatory cytokines were monitored. Additionally, the suppression capacity on the secretion of regulated on activation normal T cells expressed and secreted (RANTES) and tumor necrosis factor-α (TNF-α) in epithelial and macrophage cell-lines were evaluated. RESULTS: Compared with the virus control group, the survival rate of the QZD groups signifificantly improved in a dose-dependent manner (P<0.05), the viral titers in lung tissue was inhibited (P<0.05), and the production of inflammatory cytokines interferon-γ (IFN-γ), interleukin-6 (IL-6), TNF-α, and intercellular adhesion molecule-1 (ICAM-1) were suppressed (P<0.05). Meanwhile, the secretion of RANTETS and TNF-α by epithelial and macrophage cell-lines was inhibited with the treatment of QZD respectively in vitro (p<0.05) CONCLUSIONS: The preventive effects of QZD on influenza virus infection might be due to its unique cytokine inhibition mechanism. QZD may have significant therapeutic potential in combination with antiviral drugs.