The Study On The Effects Of Ruscogenin Against Monocrotaline-induced Pulmonary Artery Hypertension In Rats

Objective Inflammation, endothelial-dysfunction and coagulation disordercontribute to the pathogenesis and development of pulmonary hypertension.Ruscogenin is a natural product that exerts anti-inflammatory, anti-thrombotic andendothelium-protective effects，but its effects on pulmonary arteries have not yet beenelucidated. The present study was undertaken to investigate the efficacy of ruscogeninto prevent pulmonary hypertension induced by monocrotaline (MCT) in a rat model.Methods Sprague-Dawley (SD) male rats were randomly divided into five groups,each containing twelve rats:(1) Control rats;(2) MCT rats;(3) MCT ratsadministered with ruscogenin0.1mg/kg;(4) MCT rats administered with ruscogenin0.4mg/kg;(5) MCT rats administered with ruscogenin0.7mg/kg. MCT (60mg/kgbody weight) was administered intraperitoneally to induce PAH, while sterile salinewas used as the control. The solvent (distilled water with5%ethanol), ruscogenin(0.1,0.4and0.7mg/kg, dissolved in0.5ml solvent) were administered orally one dayafter the MCT or saline administration for three weeks. The survival analysisobservation continued up to day42. Severity of PAH was assessed by hemodynamicindex and histologic analysis. ELISA method was employed to measure theexpression level of interleukin-1β (IL-1β) and tissue factor (TF) in plasma and lunghomogenates, Western blot was employed to detect the protein level of nuclearfactor-kappaB (NF-κB), Akt, endothelial nitric oxide synthase (eNOS)、CD31andCaveolin-1in lung tissues. Immunohistochemical staining on lung sections was performed for the rat monocyte/macrophage marker ED-1and TF. Terminaldeoxynucleotidyl transferase mediated nick end labeling (TUNEL) staining and MTTassay were performed to detect apoptotic cell death. Data for every group werestatistically analyzed and compared.Results Ruscogenin treatment attenuated right ventricular systolic pressure (RVSP),mean pulmonary artery pressure (mPAP)，pulmonary arterial remodeling and rightventricle hypertrophy, decreased expression of inflammatory cytokine and limitedleukocyte infiltration in the lung. Treatment of rats with ruscogenin increasedexpression of eNOS, CD31, Caveolin-1and downregulated expression ofphosphorylated nuclear factor (NF)-κB in the lung tissue, improved endothelialfunction and attenuated endothelial cell apoptosis in small pulmonary arteries，restored vitality of human umbilical vein endothelial cells (HUVEC) injured byTNF-α. Furthermore, ruscogenin reduced plasma and lung TF procoagulant activityin MCT-induced PAH rats.Conclusions These results demonstrated that ruscogenin attenuated the process ofMCT-induced PAH through its anti-inflammatory, anti-coagulation andendothelial-protective properties, indicating it as a potential therapeutic agent forPAH.