[Effect of Huai Qi Huang on asthma in rats and the mechanism research].

Objective: To study the role and mechanism of action of Huai Qi Huang (HQH) in the rat model of asthma.

Methods: Forty Sprague-Dawley rats were randomly divided into a control group, an asthma model group, a budesonide group, and an HQH group, with 10 rats in each group. A rat model of asthma was established by ovalbumin sensitization and challenge. The budesonide group was given budesonide aerosol 2 mg before each challenge. The HQH group was given HQH 4 g/kg dissolved in water by gavage before each challenge. Hematoxylin and eosin staining was used to observe the pathological changes of lung tissues. The percentage of eosinophils in bronchoalveolar lavage fluid (BALF) was measured. Enzyme-linked immunosorbent assay was used to determine the levels of interleukin-3 (IL-3), interleukin-4 (IL-4), interleukin-5 (IL-5), interleukin-10 (IL-10), interferon gamma (INF-γ), and immunoglobulin E (IgE) in BALF. Flow cytometry was used to determine T-helper type 1 (Th1)/T-helper type 2 (Th2) ratio in peripheral blood and the spleen. RT-PCR and Western blot were used to measure the mRNA and protein expression of T-bet and GATA-3 in lung tissue.

Results: Compared with the control group, the asthma model group showed significant increases in the degree of airway inflammation, the percentage of eosinophils in BALF, and the levels of IL-3, IL-4, IL-5 and IgE in BALF (P<0.05), however, the asthma model group showed significant reductions in the levels of IL-10 and INF-γ in BALF (P<0.05). The asthma model group had significantly lower percentage of Th1 cells but significantly higher percentage of Th2 cells in peripheral blood and the spleen compared with the control group (P<0.05). The mRNA and protein expression of T-bet in lung tissue was significantly lower, but the mRNA and protein expression of GATA-3 in lung tissue was significantly higher in the asthma group than those in the control group (P<0.05). Both HQH and budesonide significantly improved airway inflammation and the above markers in asthmatic rats (P<0.05), with comparable effects between them. However, there were still significant differences in these indices between the control group and the HQH or budesonide group (P<0.05).

Conclusions: HQH can reduce the airway inflammation of asthmatic rats and alleviate the symptoms of asthma, possibly by regulating the levels of related cytokines and Th1/Th2 ratio through the T-bet/GATA-3 pathway.