OBJECTIVE

2

To investigate the effects of Ephedra-Cinnamomum couplet medicinals on respiratory function and airway inflammation in rats with asthma of cold-fluid retention in lung syndrome and its mechanism.

METHODS

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Sixty Wistar rats were randomly divided into blank group， model group， dexamethasone group [1 mg/（kg·d）]， and Ephedra-Cinnamomum low-， medium-， high-dose groups [0.234， 0.936， 1.872 g/（kg·d）]， with 10 rats in each group. The model and treatment groups were sensitized by intraperitoneal injection of antigen solution （ovalbumin 100 mg + aluminum hydroxide 100 mg） and challenged with 1% ovalbumin nebulization， along with exposure to a cold environment and ingestion of cold water， to establish the asthma model with cold-fluid retention in lung syndrome. From day 2， rats received corresponding drugs or normal saline intragastrically， once a day， for 21 consecutive days. The general behavioral changes in each group of rats were observed during the experimental process. The lung function parameters [peak expiratory flow （PEF）， airway resistance （Raw）， functional residual capacity （FRC）， expiratory flow at 50% of forced vital capacity （EF50%）] were measured before modeling and after the last medication as well as serum contents of interleukin-6 （IL-6）， IL-13， tumor necrosis factor-α （TNF-α） and interferon-gamma （IFN-γ） after the last medication were determined； the histopathological morphological changes in the lung tissues of rats were also observed； mRNA expressions of IL-6， IL-3， TNF-α， IFN-γ， thymic stromal lymphopoietin （TSLP）， and Toll-like receptor 4 （TLR4）， as well as protein expressions of TSLP and TLR4 were determined in lung tissue.

RESULTS

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Compared with model group， the lung tissue damage of rats was relieved significantly； Raw， FRC， the contents and mRNA expression levels of IL-6， IL-13 and TNF-α， as well as the mRNA and protein expressions of TSLP and TLR4 were significantly decreased （

P

＜0.05）， while the contents and mRNA expressions of PEF， EF50 % and IFN-γ were significantly increased in the dexamethasone group and Ephedra-Cinnamomum medium- and high-dose groups （

P

＜0.05）. Moreover， only a few rats in the two groups exhibited typical symptoms of asthma.

CONCLUSIONS

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Ephedra-Cinnamomum couplet medicinals improve respiratory function and ameliorate airway inflammation in asthma rats with cold-fluid retention in lung syndrome， the mechanism of which may be associated with inhibiting TSLP/TLR4 signaling pathway and modulating Th1/Th2 imbalance.