Lodenafil treatment in the monocrotaline model of pulmonary hypertension in rats

We assessed the effects of lodenafil on hemodynamics and inflammation in the rat model of monocrotaline-induced pulmonary hypertension (PH). Thirty male Sprague-Dawley rats were randomly divided into three groups: control; monocrotaline (experimental model); and lodenafil (experimental model followed by lodenafil treatment, p.o., 5 mg/kg daily for 28 days) Mean pulmonary artery pressure (mPAP) was obtained by right heart catheterization. We investigated right ventricular hypertrophy (RVH) and IL-1 levels in lung fragments. The number of cases of RVH was significantly higher in the monocrotaline group than in the lodenafil and control groups, as were mPAP and IL-1 levels. We conclude that lodenafil can prevent monocrotaline-induced PH, RVH, and inflammation.     

N-acylhydrazone derivative ameliorates monocrotaline-induced pulmonary hypertension through the modulation of adenosine AA2R activity

Background

Pulmonary arterial hypertension (PAH) is a disease that results in right ventricular (RV) dysfunction. While pulmonary vascular disease is the primary pathological focus, RV hypertrophy and RV dysfunction are the major determinants of prognosis in PAH. The aim of this study was to investigate the effects of (E)-N′-(3,4-dimethoxybenzylidene)-4-methoxybenzohydrazide (LASSBio-1386), an N-acylhydrazone derivative, on the lung vasculature and RV dysfunction induced by experimental PAH.

Methods

Male Wistar rats were injected with a single dose (60 mg/kg, i.p.) of monocrotaline (MCT) and given LASSBio-1386 (50 mg/kg, p.o.) or vehicle for 14 days. The hemodynamic, exercise capacity (EC), endothelial nitric oxide synthase (eNOS), adenosine A_2A receptor (A_2AR), sarcoplasmic/endoplasmic reticulum calcium ATPase (SERCA2a), phospholamban (PLB) expression, Ca^2 +-ATPase activity and vascular activity of LASSBio-1386 were evaluated.

Results and conclusions

The RV systolic pressure was elevated in the PAH model and reduced from 49.6 ± 5.0 mm Hg (MCT group) to 27.2 ± 2.1 mm Hg (MCT + LASSBio-1386 group; P < 0.05). MCT administration also impaired the EC, increased the RV and pulmonary arteriole size, and promoted endothelial dysfunction of the pulmonary artery rings. In the PAH group, the eNOS, A_2AR, SERCA2a, and PLB levels were changed compared with the control; in addition, the Ca^2 +-ATPase activity was reduced. These alterations were related with MCT-injected rats, and LASSBio-1386 had favorable effects that prevented the development of PAH. LASSBio-1386 is effective at preventing endothelial and RV dysfunction in PAH, a finding that may have important implications for ongoing clinical evaluation of A_2AR agonists for the treatment of PAH.     

Cerium oxide nanoparticles attenuate monocrotaline induced right ventricular hypertrophy following pulmonary arterial hypertension

Cerium oxide (CeO₂) nanoparticles have been posited to exhibit potent anti-oxidant activity which may allow for the use of these materials in biomedical applications. Herein, we investigate whether CeO₂ nanoparticle administration can diminish right ventricular (RV) hypertrophy following four weeks of monocrotaline (MCT)-induced pulmonary arterial hypertension (PAH). Male Sprague Dawley rats were randomly divided into three groups: control, MCT only (60 mg/kg), or MCT + CeO₂ nanoparticle treatment (60 mg/kg; 0.1 mg/kg). Compared to the control group, the RV weight to body weight ratio was 45% and 22% higher in the MCT and MCT + CeO₂ groups, respectively (p < 0.05). Doppler echocardiography demonstrated that CeO₂ nanoparticle treatment attenuated monocrotaline-induced changes in pulmonary flow and RV wall thickness. Paralleling these changes in cardiac function, CeO₂ nanoparticle treatment also diminished MCT-induced increases in right ventricular (RV) cardiomyocyte cross sectional area, β-myosin heavy chain, fibronectin expression, protein nitrosylation, protein carbonylation and cardiac superoxide levels. These changes with treatment were accompanied by a decrease in the ratio of Bax/Bcl2, diminished caspase-3 activation and reduction in serum inflammatory markers. Taken together, these data suggest that CeO₂ nanoparticle administration may attenuate the hypertrophic response of the heart following PAH.     

人参皂苷Rg2对野百合碱诱导肺动脉高压模型大鼠的作用

目的 探讨人参皂苷Rg2(ginsenoside-Rg2)对野百合碱(monocrotaline,MCT) 诱导的肺动脉高压(pulmonary arterial hypertension,PAH) 模型大鼠的作用.方法 将48只雄性SD 大鼠随机分为对照组、模型组、人参皂苷Rg2 (20、40、80 mg/kg) 组和波生坦(Bos,200 mg /kg) 组,每组8只.一次性腹腔注射MCT(50 mg/kg) 复制PAH 模型,此后按分组灌胃给药,每天1 次,连续28d.通过颈总动脉和右心室用八道生理记录仪测定右心室收缩压(right ventricle systolic pressure,RVSP)、平均动脉压(mean arterial blood pressure,MBP)、心率(heart rate,HR).处死动物后采集血浆测定内皮素-1(endothelin-1,ET-1)和一氧化氮(nitric oxide,NO)的水平并测定右心肥大指数.结果 野百合碱注射后第28天时,与对照组比较,模型组右心室压力、右心肥大指数明显升高,心率和平均动脉压明显减小;血浆ET-1水平明显增加,NO水平明显降低.人参皂苷Rg2能明显缓解这些变化.结论 人参皂苷Rg2对野百合就所致的肺动脉高压模型大鼠具有改善作用.     

不同数目骨髓间充质干细胞移植对大鼠肺动脉高压的作用及内皮素-1表达的影响

目的探讨不同数目骨髓间充质干细胞(mesenchymal stem cells,MSCs)移植对野百合碱(MCT)诱导大鼠肺动脉高压的治疗作用,以及对内皮素-1(endothelin-1,ET-1)表达的影响。方法成年雄性Wistar大鼠40只(体重180～250 g),按随机数字表法分为4组,每组10只。A组:大鼠腹腔注射MCT 60 mg/kg,经颈外静脉注入1×106MSCs;B组:大鼠腹腔注射MCT 60 mg/kg,经颈外静脉注入5×105MSCs;MCT组:大鼠腹腔注射MCT60 mg/kg和等量磷酸盐缓冲液(PBS);对照组:大鼠腹腔注入等量生理盐水和等量PBS。MSCs移植4周后测定右心室收缩压(RVSP),计算心室比,即右心室/(左心室+室间隔)[RV/(LV+VS)];观察肺组织形态学改变;检测肺组织ET-1基因表达和血清ET-1的含量。结果 MSCs移植4周后,A组RVSP和RV/(LV+VS)与MCT组比较明显降低[(35.8±4.2)mm Hg vs.(47.2±10.1)mm Hg,P<0.01;(0.357±0.032)vs.(0.452±0.056),P<0.01];而B组与MCT组比较差异无统计学意义(P>0.05)。A组肺小动脉中膜厚度较MCT组明显变薄[(19.7%±3.0%)vs.(26.8%±3.6%),P<0.01];而B组则差异无统计学意义。逆转录酶-聚合酶链反应(RTase-PCR)检测结果显示,MCT组肺组织ET-1 mRNA表达最强,A组肺组织ET-1 mRNA与MCT组比较明显减弱,B组表达与MCT组接近。A组血清ET-1含量与MCT组比较明显减少。结论 MSCs静脉移植对MCT诱导的肺动脉高压具有抑制作用,并能减少肺组织ET-1的mRNA表达及血清ET-1浓度。采用1×106MSCs移植具有较好的治疗作用。     

辛伐他汀对失代偿右心衰竭大鼠心肌氧化应激的影响

目的:观察辛伐他汀(Sim)对野百合碱(MCT)引起的失代偿右心衰竭大鼠心肌的氧化应激的影响。方法:一次性皮下注射MCT制备大鼠右心衰竭模型。注射MCT两周后,灌胃给予Sim或蒸馏水(对照组)治疗14d。测定各组大鼠右室心肌匀浆中的SOD和GSH-PX酶活力及MDA含量,以及肝和肺组织的湿重和干重的比值。结果:与正常大鼠比较,对照组大鼠右室心肌SOD和GSH-PX酶活力显著下降,心肌MDA含量及肝、肺湿重和干重的比值明显升高,(P<0.01)。Sim可有效地抑制MCT引起的心肌SOD和GSH-PX酶活力的下降及MDA含量的增加(P<0.01),并使肝、肺湿重和干重的比值降低。结论:Sim对MCT引起的失代偿右心衰竭大鼠心肌的氧化应激具有抑制作用。     

DA-8159, a potent cGMP phosphodiesterase inhibitor,attenuates monocrotaline-induced pulmonary hypertension in rats

In this study, we evaluated the effects of oral administration of DA-8159, a selective phosphodiesterase-5 inhibitor, on the development of pulmonary hypertension (PH) induced by monocrotaline (MCT). Rats were administered either MCT (60 mg/kg) or saline. MCT-treated rats were divided into three groups and received orally administered vehicle, or 1 mg/kg or 5 mg/kg of DA-8159, twice a day for twenty-one days. The MCT group demonstrated increased right ventricular weights, medial wall thickening in the pulmonary arteries, myocardial fibrosis and the level of plasma cyclic guanosine monophosphate (cGMP), along with decreased body weight gains. However, DA-8159 markedly and dose-dependently reduced the development of right ventricular hypertrophy and medial wall thickening. DA-8159 also amplified the increase in plasma cGMP level and significantly increased the level of lung cGMP, compared with the MCT group. Although the body weight gain was still lower from the saline-treated control group, DA-8159 demonstrated a significant increase in body weight gains, in both 1 mg/kg and 5 mg/kg groups, when compared with the MCT group. In myocardial morphology, MCT-induced myocardial fibrosis was markedly prevented by DA-8159. These results suggest that DA-8159 may be a useful oral treatment option for PH.     

Liver inflammation during monocrotaline hepatotoxicity

Monocrotaline (MCT) is a pyrrolizidine alkaloid (PA) plant toxin that causes hepatotoxicity in humans and animals. Human exposure occurs from consumption of contaminated grains and herbal teas and medicines. Intraperitoneal injection (i.p.) of 300 mg/kg MCT in rats produced time-dependent hepatic parenchymal cell (HPC) injury beginning at 12 h. At this time, an inflammatory infiltrate consisting of neutrophils (PMNs) appeared in areas of hepatocellular injury, and activation of the coagulation system occurred. PMN accumulation was preceded by up-regulation of the PMN chemokines cytokine-induced neutrophil chemoattractant-1 (CINC-1) and macrophage inflammatory protein-2 (MIP-2) in the liver. The monocyte chemokine, monocyte chemoattractant protein-1 (MCP-1), was also upregulated. Inhibition of Kupffer cell function with gadolinium chloride (GdCl₃) significantly reduced CINC-1 protein in plasma after MCT treatment but had no effect on hepatic PMN accumulation. Since inflammation can contribute to either pathogenesis or resolution of tissue injury, we explored inflammatory factors as a contributor to MCT hepatotoxicity. To test the hypothesis that PMNs contribute to MCT-induced HPC injury, rats were depleted of PMNs with a rabbit anti-PMN serum prior to MCT treatment. Anti-PMN treatment reduced hepatic PMN accumulation by 80% but had no effect on MCT-induced HPC injury or activation of the coagulation system. To test the hypothesis that Kupffer cells and/or tumor necrosis factor- (TNF-) are required for MCT-induced HPC injury, rats were treated with either GdCl₃ to inhibit Kupffer cell function or pentoxifylline (PTX) to prevent synthesis of TNF-. Neither treatment prevented MCT-induced HPC injury. Results from these studies suggest that PMNs, Kupffer cells and TNF- are not critical mediators of MCT hepatotoxicity. Accordingly, although inflammation occurs in the liver after MCT treatment, it is not required for HPC injury and possibly occurs secondary to hepatocellular injury.     

阿司匹林干预野百合碱诱导的大鼠肺动脉高压的研究

目的探讨阿司匹林对野百合碱(MCT)诱导的大鼠肺动脉高压的作用。方法雄性Sprague Dawley(SD)大鼠120只,随机分为6组,每组20只,分别为:正常对照组(Ctrl组)、肺动脉高压组(PAH组)和阿司匹林不同剂量治疗组(ASA 0.5组,ASA 1组,ASA 2组,ASA 4组)。PAH组、阿司匹林各剂量治疗组于第0天一次性腹腔注射MCT 50 mg/kg。从第l天开始,阿司匹林各剂量治疗组分别给予阿司匹林0.5、1.0、2.0 mg·kg~(-1)和4.0mg·kg~(-1)·d~(-1)灌胃,共30d。第31天,对各组大鼠进行以下检测:(1)统计大鼠的体质量和生存率;(2)右心导管法测定肺动脉收缩压(sPAP);(3)心脏大体标本测定右心室肥厚指数(RVHI);(4)肺组织染色切片,运用IPP 6.0图像分析软件测定肺小动脉增厚指数(PATI)。结果与PAH组比较,ASA 2组和ASA 4组体质最增加[(464.6±62.6)g和(473.2±77.2)g比(424.9±68.5)g,均为P<0.05];ASA各治疗组合计生存率较PAH组明显提高(83.75%比60.00%,P<0.05);与PAH组比较,ASA各治疗组sPAP明显下降(均为P<0.05),RVHI显著降低(均为P<0.05);除ASA 0.5组以外,其他阿同匹林治疗组的PATI较.PAH组明显降低(均为P<0.05)。结论阿司匹林1、2 mg·kg~(-1)·d~(-1)和4 mg·kg~(-1)·d~(-1)能有效降低野百合碱诱导的肺动脉高压大鼠的肺动脉压力,减轻右心室肥厚和肺小动脉增生。     

染料木黄酮通过上调血红素氧合酶-1表达减缓野百合碱诱导的大鼠肺动脉高压

目的研究染料木黄酮对野百合碱诱导的肺动脉高压大鼠肺组织血红素氧合酶-1(heme oxygenase-1,HO-1)表达的影响,探讨其减缓肺动脉高压的可能机制。方法 40只雄性SD大鼠随机分成正常对照组(n=10)、野百合碱组(n=10)、小剂量染料木黄酮治疗组(20μg/kg;n=10)、大剂量染料木黄酮治疗组(80μg/kg;n=10)。监测血流动力学变化及通过电子显微镜观察肺小动脉结构重塑,Westernblot检测肺组织HO-1的表达。结果染料木黄酮治疗组较野百合碱组大鼠平均肺动脉压降低(P<0.01),右心肥厚指数下调(P<0.01),大剂量组更显著(P<0.01)。染料木黄酮治疗组较野百合碱组大鼠肺组织HO-1表达上调(P<0.01),大剂量组更显著(P<0.01)。结论染料木黄酮能减缓野百合碱诱导的大鼠肺动脉高压,可能与上调大鼠肺组织HO-1表达有关。