Abstract: OBJECTIVE: To investigate the effect of Gubenfangxiao decoction(GBFXD) on respiratory-syncytial-virus(RSV)-induced asthma and the expression of asthma susceptibility gene, orosomucoid 1-like protein 3(ORMDL3) in mice.METHODS: Seventy-two female BALB/c mice were randomly assigned to normal, model, GBFXD high dose, GBFXD moderate dose, GBFXD low dose and montelukast groups. An asthma model was induced via intraperitoneal injection and aerosol inhalation of ovalbumin(OVA) and repeated intranasal instillation of RSV in all mice, except those in the normal group. All treatments were administered at the first onset of asthma(within 8 weeks of model establishment) and the mice were euthanized after 28 days of treatment. The levels of transforming growth factor-β(TGF-β) and interleukin-6(IL-6) in bronchoalveolar lavage fluid(BALF) of the mice were measured and the expression of asthma susceptibility gene ORMDL3 in lung tissue was determined using real-time polymerase chain reaction(RT-PCR) and western blotting.RESULTS: Expression of ORMDL3 and levels of TGF-β and IL-6 were significantly higher in the model group(P < 0.05, P < 0.01) compared with the normal mice. Levels of ORMDL3, TGF-β and IL-6 were significantly lower in all three GBFXD treated groups(P < 0.05) compared with the model group.However, the levels in the GBFXD treatment groups did not differ significantly from the montelukast group.CONCLUSION: GBFXD had a therapeutic effect in this experimental model. The functional mechanism of GBFXD may involve multiple factors, including alleviation of airway inflammation, down-regulation of asthma susceptibility gene ORMDL3 and inhibition of airway remodeling.

Key words: Asthma, ORMDL3 protein, mouse, Airway remodeling, Gubenfangxiao decoction