The effect of PS-341 on pulmonary vascular remodeling in high blood flow-induced pulmonary hypertension

The aim of the present study was to investigate the effects of PS-341 on vascular remodeling in an experimental rat model of high blood flow-induced pulmonary arterial hypertension (PAH), as well as to elucidate its mechanisms of action. We established the PAH model by a surgical method that implanted a left-to-right shunt. Three days post-surgery, the animals were randomly assigned to 3 groups (n=15 in each group): sham-operated (control), shunt (model) and PS-341 (treated) groups. Eight weeks post-surgery, hemodynamic parameters were significantly improved in the PS-341 group compared with the shunt group (P<0.05). Immunohistochemical analysis indicated that the expression levels of ubiquitin and nuclear factor-B (NF-B) p65 were significantly higher in the shunt group compared with the sham-operated group (P<0.05). Semi-quantitative western blot analysis further confirmed that the levels of ubiquitin and NF-B p65 were decreased, while those of IB- (an inhibitor of NF-B) were significantly increased in the PS-341 group compared with the shunt group (P<0.05). In conclusion, PS-341 attenuates high blood flow-induced pulmonary artery remodeling in rats via inhibition of the NF-B pathway.