ABSTRACT
<p><b>OBJECTIVE</b>To investigate the molecular mechanism of inhibitory effect of Salvia miltiorrhiza Injection (SMI) coordinated with dexamethasone (DXM) on allergic airway inflammation in asthmatic rats.</p><p><b>METHODS</b>Forty SD rats were randomly divided into 5 groups equally: the normal group, the asthma model group, the DXM group, the SMI group and the DXM + SMI group, they were treated with correspondant herbal medicines. Pathologic changes of lung tissue were obseved with HE stain, count of WBC and eosinophil (Eos) in bronchoalveolar lavage fluid (BALF) were estimated and the expressions of interleukin-13 (IL-13) and Eotaxin in lung tissue were measured by RT-PCR and SP method of immunohistochemistry assay.</p><p><b>RESULTS</b>There was moderate inflammation in lung tissue in the SMI group, and mild inflammation in the DXM + SMI and the DXM group, which was similar to that in the normal group. Compared with the asthma model group, Eos and WBC count in BALF and the expression of IL-13 and Eotaxin in the lung tissue were significantly lower in the three treated groups (P < 0.05), particularly in the DXM + SMI group, showing a significant difference as compared with the other two groups (P < 0.05 or P < 0.01). Additionally, IL-13 expression was positively correlated with Eotaxin expression (r = 0.92, P < 0.01).</p><p><b>CONCLUSION</b>SMI could inhibit the expression of IL-13 and Eotaxin in the lung of asthmatic rats, showing inhibitory effects synergistic with DXM on airway inflammation.</p>