Objective: The Shixiangru (Mosla chinensis Maxim) total flavonoids (STF) mainly contain luteolin and apigenin. The study aims to examine the inhibitory effects of STF on anti-H1N1 influenza virus and its related molecular mechanisms in pneumonia mice.
Methods: The viral pneumonia mice were treated with Ribavirin or various doses of STF. We observed histological changes of lung by immunohistochemistry and measured lung index to value anti-influenza virus effects of STF. The concentrations of inflammatory cytokines and anti-oxidant factors were detected by ELISA. RT-PCR and western blot assays were used to determine the expression level of TLR pathway's key genes and proteins in lung tissues.
Results: We found that the pathological changes of lung in the viral pneumonia mice obviously alleviated by STF treatments and the STF (288 or 576 mg/kg) could significantly decrease lung indices. Moreover, the up-regulation (IL-6, TNF-α, IFN-γ, and NO) and down-regulation (IL-2, SOD and GSH) of inflammatory cytokines and anti-oxidant factors were associated with higher clearance of virus and reduction of inflammatory lung tissue damage. Meanwhile, the expression levels of TLR3, TLR7, MyD88, TRAF3 and NF-κB p65 of the TLR pathway were reduced by STF treatment.
Conclusions: This study suggested that STF may be a promising candidate for treating H1N1 influenza and subsequent viral pneumonia.
Keywords: Anti-H1N1 influenza; Anti-oxidant factor; Cytokines; Flavonoids; Pneumonia; Toll-like receptors.