Effects of Guben Fangxiao Decoction on Airway Epithelial Tight Junction Protein and CCSP in Mice of Asthma in Remission Stage

  OBJECTIVE  To observe the effects of Guben Fangxiao Decoction (GBFXD) on airway tight junction protein and CCSP, and to explore the possible mechanism of GBFXD on airway inflammation in remission stage of asthma.

  METHODS  Mouse model of asthma in remission stage was established by sensitization and stimulation of OVA combined with respiratory syncytial virus (RSV) infection. Mice were randomLy divided into six groups (n=6): control group, model group, GBFXD low-dose group (GBFXD-L), GBFXD medium-dose group (GBFXD-M), and GBFXD high-dose group (GBFXD-H) and montelukast group.The mice were developed asthma model and given different concentrations of GBFXD (12, 24, 36 g·kg^-1)and montelukast sodium (2.6 mg·kg^-1) by gavage according to groups for 28 days. The mice were sacrificed and samples were obtained after the intervention. Hematoxylin-eosin (HE) staining was used to observe the pathological features of lung tissues in each group. The expression of CCSP in lung tissues and alveolar lavage fluid (BALF) was determined by ELISA. Western blot, qPCR and immunohistochemical assay were used to detect the expression of ZO-1 and other airway epithelial tight junction proteins in lung tissues of mice in each group.

  RESULTS  Compared with the control group, the model mice in remission stage are mainly infiltrated by inflammatory cells in the lung tissue (P < 0.01), and the infiltration of inflammatory cells in the lung tissues of mice was alleviated after the treatment (P < 0.01). The protein expression levels of ZO-1, Occludin and Desmocollin in the model group were significantly lower than those in the normal group (P < 0.05, P < 0.01), immunohistochemical results showed that the expression of the above indexes was reduced and the proteins were loosely arranged in the model group. Meanwhile, the mRNA expression levels of ZO-1, ZO-2, Vinculin and Catenin in the model group significantly decreased (P < 0.05, P < 0.01). Compared with the normal group, the expression of CCSP in the model group significantly decreased in lung tissue and BALF (P < 0.01), while the expression of CCSP in BALF and lung tissue was significantly increased by the intervention of low and high doses of GBFXD (P < 0.05, P < 0.01).

  CONCLUSION  GBFXD can repair the epithelial injury and restore the epithelial barrier function by up-regulating the expression of epithelial tight junction protein and CCSP, an indicator of epithelial cell permeability change, so as to reduce the impact of various external pathogenic factors on the airway and preventing and treating asthma.