Objective: To evaluate the effects of San'ao decoction (SAD) and its analogous prescriptions (APs), compounds of traditional Chinese herbal medicine for asthma, on airway inflammation in mice with respiratory syncytial virus (RSV)- and ovalbumin (OVA)-induced asthma.
Methods: A total of 110 mice were randomly divided into control group, untreated group, dexamethasone (DM) group, small-dose SAD (SAD-S) group, large-dose SAD (SAD-L) group, AP I-S group, AP I-L group, AP II-S group, AP II-L group, AP III-S group, and AP III-L group. The asthma model was reproduced by sensitization with multipoint intraperitoneal injection of OVA, followed by repeated inhalation of OVA combined with intranasal instillation of RSV. Cells in bronchoalveolar lavage fluid (BALF) were counted and classified. The supernatant of the BALF was used for detecting the contents of interleukin-4 (IL-4), interleukin-5 (IL-5) and interferon-gamma (IFN-gamma) by enzyme-linked immunosorbent assay. Pathological changes in lung tissue were observed by hematoxylin and eosin staining and the scores of pathological changes were also calculated to determine the degree of inflammation.
Results: Compared with the control group, the amounts of lymphocytes, eosinophils, neutrophils in BALF in the untreated group were increased significantly (P<0.01); the changes of lung histopathology in the untreated group were much more serious, and the content of IFN-gamma was sharply decreased, while the contents of IL-4 and IL-5 were significantly increased (P<0.05). The counts of eosinophils in BALF of the treated groups all decreased obviously (P<0.01) as compared with the untreated group. The count of the neutrophils in BALF of the AP II-L group was obviously lower than that in the untreated group (P<0.01). Most of Chinese herbal formulas and DM could increase the level of IFN-gamma, and decrease the level of IL-4. All concentrations of the APs and SAD could decrease the level of IL-5 as compared with the untreated group, especially of the AP II-L and AP I-L (P<0.05, P<0.01).
Conclusion: SAD and its APs had some therapeutic effects on RSV-induced asthma in mice. Among the formulas, AP II has a better therapeutic efficacy in treatment of asthma by decreasing the amount of neutrophils.