Dihydroartemisinin Attenuates Pulmonary Hypertension Via Inhibition Of Pulmonary Vascular Remodeling In Rats

Background and Objective:Pulmonary arterial hypertension(PAH)is a malignant disease characterized by pulmonary arterial remodeling due to the abnormal proliferation and migration of pulmonary arterial smooth muscle cells(PASMCs).Although a growing number of targeted vasodilators have been administered in clinical practice,the 5-year survival rate of PAH remains low,those approved drugs shown no effects on distal pulmonary vascular remodeling or plexiform lesions.Therefore,it is worthwhile to explore new therapeutic strategies to improve the long-term prognosis of PAH by inhibiting small pulmonary arterial remodeling and obliteration.Dihydroartemisinin(DHA),an artemisinin derivative that is widely used to treat malaria,has been shown to have a positive anti-tumor effect via promoting apoptosis and inhibiting neovascularization,while whether it can be beneficial in treating PAH still remains unknown.In this study,a rat model of PAH induced with monocrotaline(MCT)and a PASMCs proliferation model stimulated by platelet-derived growth factor(PDGF)were employed to test the certain effects of DHA on PAH and theunderlying mechanism.We hope this could be beneficial to the clinical treatment of PAH.Methods:A total of seventy male Sprague-Dawley rats were randomly assigned to five groups: a control group(n=12),DHA group(n=12),monocrotaline(MCT,50mg/kg)group(n=18),MCT + low dose of DHA(50 mg/kg)group(MCT+50DHA,n=14),and MCT + high dose of DHA(100 mg/kg)group(MCT+100DHA,n=14).Heart structures and functions were evaluated by echocardiography;mean pulmonary artery pressure(m PAP)and right ventricular systolic pressure(RVSP)were measured by right heart catheterization(RHC);mean systemic arterial pressure(m SAP)was measured by left common carotid artery catheterization.After hemodynamic and echocardiographic measurements,all rats were sacrificed for histological examinations as follows: heart tissues for RV hypertrophy evaluation,lung tissues for H&E staining and immunohistochemistry.Plasma sample of each rat was collected for Troponin(Tn),alanine transaminase(ALT)and serum creatinine(Cr)detection.PASMCs isolated from Sprague-Dawley rat were randomly divided into six groups: a control group,PDGF group,and other four groups with PDGF(20ng/ml)and several concentrations of DHA(5?M,10?M,20?M,or 40?M).The effect of DHA on PASMCs proliferation among groupswere examined via CCK-8 and Brd U assays.Wound-healing assay was used to detect the changes of migration in PASMCs.Western blot was employed to evaluate the levels of PCNA and the key proteins of Wnt/?-catenin signaling pathways such as: ?-catenin,p-?-catenin,Axin2,GSK-3? and p-GSK-3?.Results:Compared with MCT treatment alone,treatment with 50 mg/kg or 100mg/kg DHA significantly reduced the m PAP(P < 0.01),RVSP(P < 0.01)and pulmonary artery medial wall thickness(WT %,P < 0.01),and increased tricuspid annular plane systolic excursion(TAPSE,P < 0.05),indicating that DHA can attenuate MCT-induced PAH by inhibiting pulmonary vascular remodeling.In vitro study showed that DHA significantly inhibited PDGF-mediated PASMCs proliferation and migration in a dose dependent manner.We also found that DHA downregulated the levels of PCNA and ?-catenin while upregulating the levels of Axin2 and GSK-3?.Conclusion:DHA attenuates pulmonary arterial remodeling by blocking the proliferation and migration of PASMCs,may through the Wnt/?-catenin signaling pathway.