ObjectiveTo study the effect of modified Erchentang on the expression of key molecules in the high mobility group Box 1 protein （HMGB1）/receptor for advanced glycation endproduct （RAGE）/nuclear factor-κB （NF-κB） signaling pathway in bronchioles of rats with chronic obstructive pulmonary disease （COPD）， to explore the mechanism of modified Erchentang against bronchiolar inflammation of COPD rats via HMGB1/RAGE/NF-κB signaling pathway. MethodSixty SD rats were randomly divided into normal group， model group， modified Erchentang low-， medium- and high-dose groups （5， 10， 20 g·kg-1·d-1） and ethyl pyruvate （HMGB1 inhibitor） group， with 10 in each group. The COPD rat model was prepared by cigarette smoke combined with tracheal injection of lipopolysaccharide （LPS）. After modeling， the modified Erchentang groups were given corresponding drugs （ig） and Ringer's solution （4 mL， ip）， while the EP group was treated with equal volume of normal saline （ig） and EP （0.04 g·kg-1·d-1， ip）. The normal group and the model group received equal volume of normal saline （ig） and Ringer's solution （ip） for 21 consecutive days. The contents of HMGB1， chemokine （C-X-C motif） ligand 1 （CXCL1）， CXCL2 and monocyte chemotactic protein-1 （MCP-1） in bronchoalveolar lavage fluid （BALF） were detected by enzyme-linked immunosorbent assay （ELISA）. The mRNA expressions of HMGB1， RAGE and NF-κB p65 were determined by Real-time polymerase chain reaction （Real-time PCR）， and the protein expressions of HMGB1， RAGE， p-NF-κB p65， and alpha-smooth muscle actin （α-SMA） in bronchioles tissue of rats were determined by immunohistochemistry （IHC）. ResultCompared with the conditions in the normal group， the forced vital capacity （FVC）， forced expiratory volume in the first second （FEV1） and FEV1/FVC in the model group were decreased （P<0.01） while the contents of HMGB1， CXCL1， CXCL2 and MCP-1 in BALF were increased （P<0.01）. And the model group presented higher mRNA expressions of HMGB1， RAGE and NF-κB p65 （P<0.01） and protein expressions of HMGB1， RAGE， p-NF-κB p65 and α-SMA （P<0.05， P<0.01） than the normal group. Compared with the model group， the modified Erchentang medium- and high-dose groups had increased FEV1/FVC （P<0.05， P<0.01）， lowered contents of HMGB1， CXCL1， CXCL2 and MCP-1 in BALF （P<0.05， P<0.05）， and reduced mRNA expressions of HMGB1， RAGE and NF-κB p65 （P<0.05， P<0.01） and protein expressions of HMGB1， RAGE， p-NF-κB p65 and α-SMA （P<0.05， P<0.01）. ConclusionModified Erchentang can resist bronchiolar inflammation of COPD rats. The mechanism may be related to down-regulating the mRNA expressiona of HMGB1 and RAGE， inhibiting the activity of NF-κB， and reducing the release of HMGB1， CXCL1， CXCL2 and MCP-1， thus suppressing the inflammatory injury and abnormal repair of bronchioles.