妊娠对肺动脉高压肺循环影响的实验研究

目的:复制妊娠合并肺动脉高压大鼠模型,观察妊娠对肺循环的影响,为妊娠肺动脉高压发病机制和治疗研究奠定基础。方法:随机将71只,雌性,6周龄,SD大鼠分为四组:空白对照组(n=15),野百合碱组(MCT,n=20),妊娠组(n=16),妊娠MCT组(n=20)。饲养1周后,给MCT组及妊娠MCT组大鼠颈背部皮下注射60mg/kg MCT诱导形成肺动脉高压。2周后,妊娠组及妊娠MCT组大鼠进行合笼饲养,观察到阴栓的雌鼠被认为合笼成功。去除死亡及合笼失败的大鼠,各组最终分组如下,空白对照组(n=15),MCT组(n=12),妊娠组(n=12),妊娠MCT组(n=12)。合笼成功后于第18天利用股动脉及肺动脉插管的方法进行血流动力学数据收集,同时进行肺组织标本采集。肺组织经切片染色后显微镜下观察肺小动脉损伤情况。结果:MCT组及妊娠MCT组各自的PAP(肺动脉压)、PAP/SAP(体循环动脉压)、肺小动脉相对中膜厚度、肺小动脉密度及增厚小动脉比例均比妊娠组及空白对照组显著升高(P0.05)。妊娠MCT组大鼠PAP及PAP/SAP明显低于MCT组(P0.05),但肺小动脉密度增长更显著(P0.01)。同时妊娠组比空白对照组有更厚的肺小动脉相对中膜厚度(P0.01)。结论:本研究成功复制了妊娠合并肺动脉高压大鼠模型,发现妊娠在缓解肺高压大鼠肺循环压力增高的同时,对肺小血管的基本形态有显著影响,使肺血管阻力增高。     

妊娠对野百合碱诱导的肺动脉高压大鼠右心功能的影响

目的:采用超声心动图评价妊娠对肺动脉高压大鼠模型右心功能各参数的影响,探讨妊娠合并肺动脉高压大鼠右心功能的变化趋势。方法:将55只,6周,雌性,SD大鼠随机分成三组:肺高压组(A组n=18),妊娠合并肺高压组(B组n=25)空白对照组(C组n=12)。适应性饲养1周后,于A组和B组大鼠颈背部注射野百合碱(MCT 60 mg/kg),诱导肺动脉高压(PAH)。2周后将B组与雄鼠合笼诱导妊娠,观察到阴栓即认为妊娠成功。三组均在B组诱导妊娠前1天(T0),妊娠第3天(T3)、第9天(T9)及第15天(T15)分别进行超声心动图测量肺动脉瓣上流速(PVV)、加速时间(AT)、减速时间(DT),加速度(AS),减速度(DS),肺动脉内径(PAID),主动脉内径(AD),右心室游离壁厚度(RVWT)及右心室舒张末期内径(RVEDD)评估右心功能;并在妊娠第18天各组采用直视插管测量股动脉及肺动脉压力。结果:随时间进展,A和B组较C组的右心功能部分参数呈恶化趋势,但B组恶化程度相对较轻。在T9时间点,A组较B组RVWT增加(P0. 05);在T15时间点,A组较B组PVV降低、RVEDD增加(P0. 05); A组和B组间的AT、DT、PAID/AD、AS、DS无明显差异。在T18时间点,A组、B组较C组肺动脉压力升高(P0. 05),但B组较A组明显降低(P0. 05)。结论:对野百合碱诱导的肺动脉高压大鼠,妊娠可以一定程度上缓解右心功能的恶化,并且晚期肺动脉压力相对较低。     

缝隙连接蛋白43在大鼠肺动脉高压及波生坦干预后表达的变化

目的:研究肺小动脉内皮细胞问缝隙连接蛋白(Cx)43在大鼠肺动脉高压及波生坦(bosentan)干预后表达的变化.方法:10只SD大鼠为正常对照组(n=10),不做任何处理.57只SD大鼠通过大鼠腹腔内注射野百合碱(MCT,60 ms/kg)两周后,随即将人鼠分成2组,具体分组如下:肺动脉高压大鼠+安慰剂组(n=35),肺动脉高压大鼠+bosentan组(n=22).通过胃管予以安慰剂或双通道内皮素受体拮抗剂[bosentan,300 ms/(kg-d)]治疗,每天1次,共计3周.免疫荧光的方法测定Cx43和Cx37在肺小动脉中层平滑肌细胞问和内皮细胞间表达的变化.结果:与正常对照组比,肺动脉高压大鼠+安慰剂组的肺小动脉中层平滑肌厚度和血管外周直径的比值(WT%)、肺动脉平均压均明显增加(P均<0.01),肺动脉高压大鼠+bosentan组的WT%较肺动脉高压大鼠+安慰剂组显著减小(P<0.01).在正常对照组的肺小动脉内皮细胞间未检测到Cx43,而在怖动脉高压大鼠+安慰剂组和肺动脉高压大鼠+bosentan组,内皮细胞间均可见Cx43表达,其表达量在肺动脉高压人鼠+bosentan组显著少于肺动脉高压大鼠+安慰剂组(P<0.01).3组肺小动脉内皮细胞间均可见Cx37的表达,但3组间的表达量差异无统计学意义.结论:在肺动脉高压中肺小动脉内皮细胞间出现Cx43的异常表达,经bosentan治疗后Cx43的表达水平显著下降.     

二十二碳六烯酸对肺动脉高压大鼠活化T细胞核因子c1表达的影响

目的观察二十二碳六烯酸(DHA)对野百合碱(MCT)致肺动脉高压(PH)大鼠肺血管重构及活化T细胞核因子c1(NFATc1)表达的影响。方法 24只SD大鼠随机分为正常对照组(n=7)、DHA干预组(n=7)及MCT模型组(n=10)。肺动脉高压模型采用MCT诱导法,HE染色观察大鼠肺小动脉形态学改变,免疫组织化学、Western blot和qRT-PCR检测大鼠肺动脉NFATc1蛋白和mRNA的表达。结果 DHA能明显减轻模型大鼠的肺血管重构;与正常对照组相比,MCT模型组肺动脉NFATc1蛋白和mRNA的表达明显增强(P0.05);与MCT模型组相比,DHA干预组肺动脉NFATc1蛋白和mRNA的表达减弱(P0.05)。结论 DHA对MCT所致肺动脉高压具有较好的抑制作用,其作用机制可能与其抑制NFATc1表达有关。     

自发性高血压大鼠主动脉血管功能的变化

目的探讨自发性高血压大鼠(SHR)血管舒缩功能变化及其可能机制.方法以32周龄SHR大鼠(n=7)为研究对象,年龄、性别配对的WKY(n=7)大鼠作对照组.观察离体胸主动脉环对不同血管活性物质的舒缩反应.结果 SHR主动脉环对乙酰胆碱(ACh)诱导的内皮依赖性舒张反应明显减弱;对ACh的内皮依赖性收缩反应明显高于WKY.L-NAME加强ACh的收缩作用;对硝普钠(SNP)的收缩反应在两组间无差别.结论 SHR大鼠存在内皮功能障碍,表现为内皮依赖性舒张作用减弱,其机制与内皮合成NO减少及内皮依赖性收缩作用增强有关.     

内皮祖细胞移植对肺动脉高压大鼠血流动力学及肺血管结构的影响

目的 探讨大鼠内皮祖细胞(EPC)移植对野百合碱(MCT)所致大鼠肺动脉高压(PAH)的血流动力学及肺血管结构的影响.方法 体外培养,鉴定EPCs.用MCT诱发的PAH模型组(n=11)大鼠,由尾静脉注入标记的EPC,移植第21天测定肺血流动力学参数,计算平均肺动脉压(MPAP),右心指数.观察EPCs移植后分化为血管内皮细胞的能力及肺血管结构变化.结果 移植EPC 3周后,荧光显微镜观察部分标记的EPCs分化为血管内皮细胞.与模型组相比,EPC治疗组(n=10)MPAP明显下降[(25.9±0.7)比(29.35±2.2)mmHg,P<0.05],右心指数明显下降(0.43±0.04比0.49±0.05,P<0.05),肺小动脉厚度指数[WT%:(17.7±3.8)%比(29.8±4.3)%]和面积指数[WA%:(54.6±3.9)%比(74.8±4.5)%]明显下降(P均<0.05).结论 同种异体EPC移植可有效降低肺动脉压力,肺动脉血管壁厚度指标和面积指数,改善右心肥厚.作用机制尚需进一步研究.     

内皮祖细胞移植对肺动脉高压大鼠血流动力学及肺血管结构的影响

目的探讨大鼠内皮祖细胞(EPC)移植对野百合碱(MCT)所致大鼠肺动脉高压(PAH)的血流动力学及肺血管结构的影响。方法体外培养,鉴定 EPCs。用 MCT 诱发的 PAH 模型组(n=11)大鼠,由尾静脉注入标记的 EPC,移植第21天测定肺血流动力学参数,计算平均肺动脉压(MPAP),右心指数。观察 EPCs 移植后分化为血管内皮细胞的能力及肺血管结构变化。结果移植 EPC 3周后,荧光显微镜观察部分标记的 EPCs 分化为血管内皮细胞。与模型组相比,EPC 治疗组(n=10)MPAP 明显下降[(25.9±0.7)比(29.3±2.2)mmHg,P<0.05],右心指数明显下降(0.43±0.04比0.49±0.05,P<0.05),肺小动脉厚度指数[WT%:(17.7±3.8)%比(29.8±4.3)%]和面积指数[WA%:(54.6±3.9)%比(74.8±4.5)%]明显下降(P 均<0.05)。结论同种异体 EPC 移植可有效降低肺动脉压力,肺动脉血管壁厚度指标和面积指数,改善右心肥厚。作用机制尚需进一步研究。     

川崎病致肺动脉内皮损伤和肺动脉高压的实验研究

目的 探讨川崎病(KD)对肺血管内皮功能的影响以及与肺动脉高压发生的相关性。方法 采用干酪乳杆菌细胞壁成分(LCWE)建立川崎病大鼠模型,将40只(1月龄)SD大鼠随机分为对照组和KD组,KD组大鼠腹腔注射LCWE 0.5 ml(1 mg/ml)来建造KD模型。造模2周后采用组织病理学评估冠状动脉和肺动脉的损伤情况。测定大鼠体循环压力、右心室压力和右心室肥厚指数、肺小动脉舒张功能。检测肺小动脉组织抗氧化酶锰超氧化物歧化酶(MnSOD)和过氧化氢酶(Catalase)的表达水平,以及氧化应激水平。结果 LCWE注射14 d后,与对照组比较,成功诱导KD大鼠冠状动脉损伤(P<0.05),KD组大鼠出现肺组织损伤,肺组织水肿,点、片状出血,伴中性粒细胞为主的炎性细胞浸润。肺小动脉内皮细胞肿胀,中膜层出现不规则间断性肥厚,管腔呈部分狭窄,肺动脉损伤评分升高(P<0.05)。肺小动脉组织MnSOD和Catalase的表达水平较对照组显著降低(P<0.05),髓过氧化物酶(MPO)、丙二醛(MDA)水平明显升高(P<0.05)。同时,KD组大鼠右心室压力和肥厚指数较对照组明显升高(P<0.05),离体血管灌流实验证实,KD组大鼠肺小动脉内皮依赖性的舒张作用明显减弱(P<0.01)。结论 KD可导致肺小动脉血管炎,引发肺小动脉血管内皮损伤和氧化应激损伤,可能是诱发肺动脉高压和继发性心脏损伤的重要原因之一。     

17-β雌二醇干预对妊娠合并肺高压大鼠肺循环的影响

目的:建立17β-雌二醇(E2)干预野百合碱(MCT)诱导的妊娠合并肺动脉高压大鼠模型,观察E2对肺循环的影响,为雌激素的替代疗法奠定基础。方法:将7周,雌性,SD大鼠,75只随机分为四组:正常妊娠组(A组,n=15),妊娠+MCT组(B组,n=20),孕中期E_2干预妊娠+MCT组(C组,n=20),分娩后E_2干预妊娠+MCT组(D组,n=20)。适应性饲养一周后B、C、D组大鼠颈背部注射MCT 60 mg/kg。两周后四组大鼠与雄鼠合笼,观察到阴栓即为妊娠(PD0)。从妊娠第16天(PD16)至分娩后第3天(D3),C组每日肌肉注射30μg/kg E2,A、B组每日肌肉注射等容量0.9%氯化钠溶液;D组从分娩后当天(D1)每日肌肉注射30μg/kg E2直到D3。B、C、D三组大鼠于PD15、19、D3测E2含量。四组大鼠于PD19、D3测肺动脉压力(PAP),D3取心脏组织计算右心肥厚指数(RVHI),取肺组织切片染色观察肺微动脉形态。结果:PAP:B组在PD19和D3均显著高于A组(P0.001);C组较B、D组在PD19、D3均明显降低(P0.001);(2)E2含量:C组较B、D组在PD19和D3均明显增高(P0.05);D组较B组在D3明显增高(P0.001)。③RVHI:C、D组较B组均明显降低(P0.001);C、D两组差异无统计学意义(P0.05)。④肺微动脉形态:B、C、D组较A组均可见肺微动脉中膜增厚,B、D组增厚更明显(P0.05)。结论:E2干预可显著降低妊娠合并肺动脉高压大鼠肺动脉压力。在妊娠中期干预更明显,且能一定程度上延缓肺微动脉中膜增厚。不同干预时间对右心肥厚指数影响不大。     

槲皮素对野百合碱诱导的大鼠肺动脉高压的影响

目的:观察槲皮素对野百合碱(MCT)诱导的肺动脉高压大鼠的治疗效果。方法:30只成年雄性SD大鼠随机分成3组:MCT诱导的肺动脉高压组(MCT组)、治疗组和对照组。MCT组和治疗组一次性皮下注射MCT 50mg/kg,饲养21d;对照组一次性皮下注射等量0.9%氯化钠溶液,饲养21d。造模后治疗组以槲皮素100mg.kg-1.d-1灌胃20d;MCT组和对照组以0.9%氯化钠溶液2ml/d灌胃20d。20d后,测定3组大鼠平均肺动脉压(mPAP),计算右心室肥大指数(RVHI);光镜下观察大鼠肺组织形态学的改变及肺血管增殖细胞核抗原(PCNA)增殖度的变化,并计算肺中、小动脉管壁厚度占血管外径的百分比(WT%)和肺动脉管壁面积/管总面积的百分比(WA%)。结果:MCT组的mPAP、RVHI、肺中、小动脉WT%、WA%及PCNA增殖度均显著高于对照组及治疗组。结论:槲皮素可降低MCT所致的大鼠肺血管PCNA表达,抑制MCT诱导的肺部炎症、肺血管重建和肺动脉高压形成,对MCT所致的大鼠肺动脉高压具有治疗作用。     

Effect of increase of pulmonary blood flow on segmental pulmonary vascular resistance--with special emphasis on the pulmonary capillary bed]

The decrease of pulmonary vascular resistance with increase of pulmonary blood flow has been attributed to the function of the pulmonary vascular bed, consisting of capillary recruitment or dilatation. However, experimental evidence of a decrease of capillary resistance is lacking. To clarify this phenomenon, we perfused isolated cat lungs with diluted autologous blood and measured pulmonary microvascular pressure while changing pulmonary blood flow rate. We set the initial flow rate to achieve Ppa of 20 cmH2O and changed the flow rate while keeping left atrial pressure (Pla) and alveolar pressure (Palv) constant at 10 cmH2O and 9 cmH2O, respectively. Thereafter, pulmonary flow rate was increased 2 to 3 fold, and pulmonary arterial pressure (Ppa) and venular pressure (Pvo) were measured by venous occlusion method. The initial flow rate was 150 to 270 ml/min and the achieved maximum flow rate was from 300 to 543 ml/min. There was a linear correlation between Ppa, Pvo, and flow rate, in which the slope (rate of increase of pressure with flow) of Ppa was slightly steeper than that of Pvo. We calculated total and segmental pulmonary vascular resistance from the mean pressure-flow relationship. The total and upstream resistance involving arterial and capillary segments decreased hyperbolically with increase in flow rate. The mean upstream resistance decreased about 54%, from 35.20 x 10(-3) (cmH2O/ml/min) at a flow rate of 150 ml/min to 16.27 x 10(-3) (cmH2O/ml/min) at a flow rate of 450 ml/min. The degree of this decrease was similar to the result observed by micropuncture method (Nagasaka, 1990). Downstream resistance, which represents venous resistance, did not change significantly with the flow rate.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term effects of epoprostenol on the pulmonary vasculature in idiopathic pulmonary arterial hypertension

The current treatment of pulmonary arterial hypertension (PAH) uses vasodilator drugs. Although they improve symptoms associated with PAH, their chronic effects on the pulmonary vasculature and the right ventricle (RV) in humans remain unknown. We report the autopsy findings from a patient with idiopathic PAH treated with epoprostenol successfully for 18 years. The patient died of colon cancer. The pulmonary vasculature surprisingly showed extensive changes of a proliferative vasculopathy. Immunohistochemical studies confirmed ongoing cellular proliferation. Studies of the RV demonstrated concentric hypertrophy with seemingly preserved contractility. The myocardium shifted to glycolytic metabolism. Although the long-term use of epoprostenol contributed to the patient's increased survival, it did not prevent progression of the underlying vascular disease. Remarkably, the RV was able to sustain a normal cardiac output in the face of advanced vascular pathology. The mechanisms by which the RV adapts to chronic PAH need further study.     

Studies on the mechanism of pulmonary vascular responses to miliary pulmonary embolism.

The nature and mechanisms of pulmonary vascular responses which follow miliary pulmonary embolism were examined in intact dogs in which the isolated left lower lobe was perfused at constant blood flow. Embolization of the lung with plastic microspheres increased total pulmonary vascular resistance, whereas, in contrast, vascular resistance of the isolated perfused left lower lobe which was protected from embolization was decreased. This vasodilation was prevented by chronic denervation of the lobe and by ganglionic blockade. Cervical vagotomy also blocked the response but atropine failed to alter the vasodilation. The response, which appeared to be reflex in origin and involve efferent sympathetic pathways, was prevented by beta-adrenergic receptor blockade produced by propranolol. Since the lobar vascular response to norepinephrine was significantly enhanced by propranolol, it was concluded that embolization of the lung evokes pulmonary vascular reflex vasodilation which is mediated over the sympathetic nervous system via a beta-adrenergic receptor mechanism.