[Abstract ] Objective Chronic obstructive pulmonary disease (COPD) is closely related to pulmonary hypertension .This study was to investigate the correlation of the expression of high mobility group protein B 1 ( HMGB1) with its synthesis and secretion of interferon-γ( IFN-γ) in the distal pulmonary arterial smooth muscle cells ( PASMCs ) of COPD rats and its clinical significance . Methods We established COPD models in rats , primarily cultured and identified PASMCs , and detected the synthesis and secretion of cytokine in the PASMCs induced by cigarette smoke extract (CSE) and/or lipopolysaccharide (LPS).The PASMCs in the control, CSE, LPS, and CSE+LPS groups were cultured with anti-HMGB1 antibodies at 0.2 mL 1∶1000.At 12, 24, 48 and 72 hours of inter-vention, the expression of HMGB1 in the PASMCs was detected by Western blot and the concentrations of HMGB 1 and IFN-γin the cell culture supernatant were measured by ELISA , followed by a correlation analysis . Results Light microscopy manifested a peak -valley growth pattern or fusiform shape of the cells , which were identified as PASMCs by α-actin immunohistochemistry and immuno-fluorescence .Western blot and ELISA showed statistically significant differences in the expression of HMGB 1 and concentrations of cell supernatant HMGB1 and IFN-γat 12 hours between any two of the four groups (P<0.05).The HMGB1 expression level was positive-ly correlated with the concentration of IFN-γ(r=0.91), obviously decreased after 12 hours of intervention with anti-HMGB1 antibod-ies as compared with the corresponding experimental groups ( P <0.05).Western blot and ELISA showed no significant differences within the same group at 12, 24, 48 and 72 hours (P>0.05). Conclusion The expression level of HMGB1 was positively correla-ted with the synthesis and secretion of IFN-γin the distal PASMCs of the COPD model rats , and anti-HMGB1 antibodies provide a new in-tervention target for the clinical treatment of COPD and inhibition of its systemic inflammatory response .