Wanglaoji Herbal Tea Protects Against Influenza-Induced Pneumonia In Restraint-Stressed Mice Via Its Anti-Inflammatory Effects

Background and Objective: Wanglaoji Herbal Tea (WHT) is considered a traditional remedy for "Shanghuo" in Southern China. Studies have proven that WHT has the potential to modulate immunity against viral epidemics. However, experimental data supporting the pharmacological activities of WHT are limited. The current study aimed to investigate the protective effects and related mechanisms of WHT against influenza induced pneumonia in mice exposed to restraint stress. Materials and Methods: In this study, restraint-stressed mice infected with A/FM/1/47 (H1N1) virus were employed as the model to investigate the anti-inflammatory effects of WHT. On the second day of oral administration of WHT, all mice except the normal and virus control groups were restrained for 18 h. Mice were infected with influenza virus after recovering from restraint stress for 3 days. Body weight, morbidity and mortality were recorded daily for 21 days. In addition, the oxidative activity (MDA, SOD and iNOS), inflammatory markers (TNF-alpha and IL-1 beta), histopathologic changes, influenza-related mRNA expression (NP) and influenza-related protein expressions (MAVS, p-IRF3, IFN-beta and NF-kappa B) in the lung tissues were determined on the fourth day of post-viral infection. The data was statistically analyzed by one-way ANOVA using the SPSS software (Version 19). Multiple Tukey's post hoc test was used to determine the statistical significance. Results: The results showed that WHT reduced morbidity and mortality. Meanwhile, WHT ameliorated oxidative damage by decreasing the level of MDA and increasing SOD activity. Further experimental results showed that WHT not only improved mitochondrial antiviral signaling protein (MAVS) and p-IRF3 protein expression to promote the IFN-beta responses but also down-regulated NF-kappa B protein expression to dampen excessive inflammatory cytokine responses in the restraint-stressed mice infected with the influenza virus. These results demonstrated that WHT elevated the hosts' immune system and ameliorated influenza-induced pneumonia. Conclusion: The WHT reduces pneumonia caused by influenza virus infection in restraint-stressed mice by regulating the MAVS antiviral signaling pathway.