Effects of Ligustrazine on Airway Inflammation in A Mouse Model of Neutrophilic Asthma

Objective: To investigate the effects of ligustrazine(LTZ) on airway inflammation in a mouse model of neutrophilic asthma(NA). Methods: Forty healthy C57 BL/6 female mice were randomly divided into 4 groups using a random number table, including the normal control, NA, LTZ and dexamethasone(DXM) groups, with 10 rats in each group. The NA mice model was established by the method of ovalbumin combined with lipopolysaccharide sensitization. At 0.5 h before each challenge, LTZ and DXM groups were intraperitoneally injected with LTZ(80 mg/kg) or DXM(0.5 mg/kg) for 14 d, respectively, while the other two groups were given the equal volume of normal saline. After last challenge for 24 h, the aerosol inhalation of methacholine was performed and the airway reactivity was measured. The bronchoalveolar lavage fluid(BALF) was collected. The Wright-Giemsa staining was used for total white blood cells and differential counts. The levels of cytokines interleukin(IL)-17 and IL-10 were detected by enzyme-linked immunosorbent assay. The pathological change of lung tissue was observed by hematoxylin eosin staining. Results: The airway responsiveness of the NA group was significantly higher than the normal control group(P<0.05), while those in the LTZ and DXM groups were significantly lower than the NA group(P<0.05). The neutrophil and eosinophil counts in the LTZ and DXM groups were significantly lower than the NA group(P<0.05), and those in the LTZ group were significantly lower than the DXM group(P<0.05). There were a large number of peribronchiolar and perivascular inflammatory cells in filtration in the NA group. The airway inflammation in the LTZ and DXM groups were significantly alleviated than the NA group. The infiltration in the LTZ group was significantly reduced than the DXM group. Compared with the normal control group, the IL-17 level in BALF was significantly increased and the IL-10 level in BALF was significantly decreased in the NA group(P<0.05). LTZ and DXM treatment significantly decreased IL-17 levels and increased IL-10 levels compared with the NA group(P<0.05), and the changes in the above indices were more significant in the LTZ group(P<0.05). Conclusion: LTZ could alleviate the airway inflammation in the NA mice model through increasing the IL-10 level and decreasing the IL-17 level.