Curcumin improves airway inflammation and mucus hypersecretion by inhibiting IL-13/STAT6 signaling pathway in asthmatic rats

Objective To explore the effects of curcumin on airway inflammation, airway goblet cells metaplasia and mucus secretion through interleukin-13 (IL-13)/signal transducers activator of transcription 6 (STAT6) signaling pathway in asthmatic rats. Methods Twenty-four female SD rats were randomly divided into four groups: negative control group, asthma model group, curcumin group and dexamethasone group (n=6). For asthma model establishing, the rats were sensitized and challenged with ovalbumin, while the negative controls received saline.The lung tissue sections were stained with hematoxylin-eosin staining for histopathological examinationand the number of airway epithelium goblet cells were examined with periodic acid-schiff stain.The concentration of MUC5AC and IL-13 in bronchoalveolar lavage fluid (BALF) was measured by enzyme linked immunosorbent assay, and the expression of MUC5AC in airway epithelial cells were demonstrated by immunohis to chemistry.The p-STAT6 protein expression were detected by Western Blot. Results Compared with the negative control group, the infiltration of inflammatory cells was observed in the lung tissue of the asthma model group, the number of goblet cells was significantly increased, the proportion of eosinophils, the concentration of MUC5AC and IL-13 in BALF were significantly increased (P 0.05). Conclusions Curcumin can inhibit the metaplasia of airway epithelial goblet cells and decrease the expression of MUC5AC in airway epithelium of asthmatic rats.The mechanism of curcumin may be achieved by inhibiting the activity of IL-13/STAT6 signaling pathway. Key words: Asthma; Curcumin; Goblet cells; Interleukin-13