The therapeutic effects of sodium cromoglycate against influenza A virus H5N1 in mice

OBJECTIVES To identify the protective role of sodium cromoglycate in mice during influenza virus infection. DESIGN H5N1 virus-infected mice were treated with the mast cell stabilizer sodium cromoglycate (SCG) to investigate its therapeutic effect. SAMPLE The nose, trachea and lungs from mice were collected. MAIN OUTCOME MEASURES Virus replication and host responses were determined by plaque assay, quantitative PCR, immunohistochemistry, and histology. RESULTS SCG-treated mice survived better than did PBS-treated mice after H5N1 virus infection. Mild pathological changes with fewer inflammatory cell infiltration and fewer virus antigens were observed in the nose, trachea, and lungs of SCG-treated mice on days 3 and 5 post-infection. However, no significant changes in viral load in the lungs were detected between SCG- and PBS-treated mice. Furthermore, significantly decreased expression of interleukin-6, tumor necrosis factor-a, Toll-like receptor 3, and TIR-domain-containing adapter-inducing interferon-b was detected in the lungs of SCG-treated mice, and no higher expression of interferon-c was detected. CONCLUSION These results suggest that SCG has therapeutic roles in H5N1 virus-infected mice by alleviating the inflammatory response rather than inhibition of viral replication in the lungs.