Angiotensin II and monocrotaline-induced pulmonary hypertension: effect of losartan (DuP 753), a nonpeptide angiotensin type 1 receptor antagonist.

Administration of the pyrrolizidine alkaloid monocrotaline (MCT) to rats results in hypertensive pulmonary vascular disease characterized by a structurally based increase in pulmonary vascular resistance and right ventricular hypertrophy. Alterations in lung angiotensin converting enzyme activity in MCT-treated rats have suggested a role for angiotensin II (AII) in the pathogenesis of this model of hypertensive pulmonary vascular disease. To determine if increases in AII contribute to the development of pulmonary hypertension in MCT-treated rats, we examined the effect of chronic administration of the nonpeptide AII receptor antagonist Losartan on indices of pulmonary hypertension, Losartan (DuP 753; 10 mg/kg s.c.) administration for 21 days did not prevent the development of hypertensive pulmonary vascular disease in MCT-treated rats. However, 18 hr after the last dose of Losartan, AII (0.1 micrograms/kg i.v.)-induced pressor responses were inhibited by 63% in Losartan-treated rats. Losartan administration in MCT-treated rats did not prevent increases in pulmonary artery pressure or development of right ventricular hypertrophy. Additionally, increases in medial arterial thickness in pulmonary artery vessels (less than 50 microns and 50-100 microns external diameter) from MCT-treated rats were still evident in Losartan-treated rats. However, Losartan administration decreased medial pulmonary artery thickness of 50 to 100 microns external diameter vessels in control rats. These results demonstrate that AII. acting at the AT1 receptor subtype, does not contribute to pulmonary hypertension in this animal model.     

内膜新生性肺血管重构肺动脉高压大鼠模型的建立及评价

背景：目前尚缺乏简单易行、实用、操作性强的血管内膜新生性肺血管重构肺动脉高压动物模型。目的：建立内膜新生性肺血管重构大鼠肺动脉高压模型。方法：40只雄性SD大鼠随机分为2组：M＋P组（n=26）大鼠行左肺切除,2周后皮下注射野百合碱60mg/kg;对照组（n=14）大鼠仅行假手术处理。于术后5周检测肺动脉压、右心室/（左心室＋室间隔）质量的比值,同时观察右肺动脉病理形态学改变。以光镜下每1mm2面积内Ⅷ因子标记阳性的直径小于100μm的肺血管数评价肺内微血管密度。结果与结论：M＋P组大鼠存活率85%（22/26）,对照组存活率为100%（14/14）。与对照组相比,M＋P组大鼠肺动脉压力和右心室/（左心室＋室间隔）质量的比值明显增高（P〈0.01）;与对照组相比,M＋P组大鼠肺内直径为50-100μm和100-150μm的肌型小动脉中膜相对厚度均显著增加（P〈0.01）,肺内微血管密度显著减少（P〈0.01）。光镜显示M＋P组大鼠注射野百合碱后5周肌型肺小动脉中膜明显增厚,肺腺泡内小动脉明显肌化、内膜增厚。对照组大鼠肺小动脉未见血管结构重建。实验成功建立了内膜新生性肺血管重构大鼠肺动脉高压模型,操作相时简便,动物死亡率较低。     

Age-related decrease in beta adrenergic receptor-mediated vascular smooth muscle relaxation

Beta adrenergic receptor-mediated vascular smooth muscle relaxation decreases with increasing age. We have examined the mechanism responsible for this phenomenon using rat mesenteric arteries from young (5-6 weeks) and older (10-12 months) rats. The beta adrenergic agonist isoproterenol produced a dose-dependent relaxation of serotonin-constricted mesenteric artery rings from young rats, whereas the maximal ability of isoproterenol to relax arterial rings from the older rats was found to be reduced markedly (92.7 vs. 27.6%, P less than .0001). The relaxation responses caused by acetylcholine and nitroglycerin, which appear to act independently of cyclic AMP (cAMP), are similar in the two groups. The loss in responsiveness of the mesenteric artery to isoproterenol was not explained by a change in beta receptor number in the vessels (29 +/- 4 in young rats vs. 31 +/- 7 fmol/mg of protein in the older rats). The maximal stimulation of cAMP accumulation by isoproterenol was lower in the older vessels; forskolin activated cAMP accumulation equally in the two groups. However, the vessels from the older rats were less sensitive to forskolin-induced vascular relaxation. Also, the ability of dibutyryl cAMP to promote vascular relaxation was diminished in the older vessels. These data suggest that the diminished cAMP accumulation in older vessels in response to isoproterenol might not necessarily in itself explain completely the reduced physiological response and that an additional defect in the beta adrenergic-mediated relaxation in the vascular smooth muscle of older rats may lie at the level of cAMP-dependent protein kinase activation or more distally.     

Acetylcholine-induced contractions in isolated rabbit pulmonary arteries: role of thromboxane A2

Acetylcholine has been reported to produce vasodilation or vasoconstriction in the pulmonary circulation of different species. In rabbit lungs, acetylcholine is a potent vasoconstrictor. The present study was undertaken to examine the contractile effects of acetylcholine in arteries isolated from various regions of the rabbit pulmonary vascular bed and in thoracic aorta. Arteries isolated from within the lung were more responsive than extrapulmonary arteries (main pulmonary artery and aorta) to the contractile effects of acetylcholine. In vessels precontracted with norepinephrine, acetylcholine caused biphasic (relaxation-contraction) concentration-response curves. Atropine inhibited acetylcholine-induced contractions in all vessels, whereas pretreatment with cyclooxygenase or thromboxane synthetase inhibitors abolished contractile responses to acetylcholine only in intrapulmonary arteries. In accordance with these findings, acetylcholine caused a 3-fold increase in thromboxane A2 release from intrapulmonary arteries but not from extrapulmonary arteries. Inhibition of thromboxane synthetase abolished this effect of acetylcholine. Endothelium removal decreased contractile responses in intrapulmonary arteries but it did not decrease contractions in extrapulmonary arteries, suggesting that endothelium may contribute to acetylcholine-induced, thromboxane-mediated contractions in intrapulmonary arteries. Indomethacin did not inhibit contractile responses in endothelium-denuded main pulmonary artery or aorta but it abolished the weak contractile responses in intrapulmonary arteries without endothelium, indicating that arterial smooth muscle also was a source of contractile prostanoid biosynthesis enhanced by acetylcholine. These results demonstrate that acetylcholine contracts rabbit intrapulmonary arteries through generation of thromboxane A2 but that a different mechanism is responsible for mediating weaker acetylcholine-induced contractions in extrapulmonary artery and aorta.(ABSTRACT TRUNCATED AT 250 WORDS)     

The role of vascular injury and hemodynamics in rat pulmonary artery remodeling.

Vascular remodeling in adult human elastic pulmonary arteries is characterized by diffuse neointimal lesions containing smooth muscle cells expressing extracellular matrix genes. Recent studies suggest vascular injury is needed to initiate remodeling and that growth factor mediators participate in the repair response. However, because neointimal formation is only observed in patients with pulmonary artery blood pressures approaching systemic levels, it has been hypothesized that systemic-like hemodynamic conditions are also necessary. To test that hypothesis, subclavian-pulmonary artery anastomoses were created in Sprague-Dawley rats under three different experimental conditions: no accompanying injury, or after monocrotaline or balloon endarterectomy injury. Pulmonary vascular remodeling was not induced by the subclavian-pulmonary artery anastomosis alone. A non-neointimal pattern of remodeling after mild monocrotaline-induced injury was converted into a neointimal pattern in the presence of the anastomosis. Neointima was also observed after severe, balloon endarterectomy-induced injury even in the absence of anastomosis. Tropoelastin, type I procollagen and TGF-beta gene expression, and angiotensin converting enzyme immunoreactivity, was confined to the neointima resembling the pattern of gene expression and immunoreactivity in human hypertensive elastic pulmonary artery neointimal lesions. These observations introduce the concepts that the type of injury and the associated hemodynamic conditions can modify the elastic pulmonary artery response to injury.     

Na+/K(+)-adenosine triphosphatase activity of pulmonary arteries after intoxication with the pyrrolizidine alkaloid, monocrotaline

Na+/K(+)-Adenosine triphosphatase-dependent activities of K(+)- return relaxation and 86Rb uptake were studied in pulmonary arteries taken from rats with pulmonary hypertension induced by monocrotaline. Rats were given monocrotaline in drinking water, 20 mg/l, for 4 or more days. Isolated arteries were placed in tissue baths and contracted with norepinephrine or 5-hydroxy-tryptamine under K(+)-free conditions. The arteries relaxed when K+ was "returned" to the bath. Compared to arteries from untreated rats, arteries taken from rats pretreated with monocrotaline developed less force in response to contracting agents and did not relax to the same extent. After 4 days treatment with monocrotaline, the rate of relaxation of the arteries in response to K(+)-return was slower than that of arteries taken from untreated rats. Endothelial trauma or in vitro treatment with ouabain produced a similar decrease in the rate of relaxation. Uptake of radiolabeled Rb by perfused arteries was not altered by 4 days of monocrotaline pretreatment. Isolated lungs taken from monocrotaline-pretreated rats (5 days of ingestion of 20 mg/l of monocrotaline drinking water) accumulated similar quantities of 86Rb+ during 40-sec perfusions. Shorter perfusion times, 10 and 20 sec, resulted in greater rates of uptake of 86Rb- by lungs taken from monocrotaline-treated rats. Monocrotaline produced changes in both the mechanical and biochemical properties of pulmonary arteries after only 4 to 5 days. These changes were associated with ouabain-sensitive processes. It appears, therefore, that one of the early targets in monocrotaline intoxication is the Na+/K+ pump of the pulmonary arteries.     

Age-related changes in relaxant response of vascular smooth muscles to atrial natriuretic peptide

The effect of aging on responses of vascular smooth muscles to atrial natriuretic peptide (ANP) and other vasodilator substances was investigated in isolated rat aortae, rat renal arteries and monkey renal arteries which were precontracted with norepinephrine. There was no significant difference in the ANP-induced maximum relaxation between young and old rat aortae. However, the concentration of agonists causing a 50% relaxation (ED50) value for the old rats was 7.3 times greater than that for the young ones. In rat and monkey renal arteries, the ED50 ratios were 6.2 and 3.8, respectively. The relaxant responses of the rat aortae to isoproterenol and acetylcholine also decreased with increasing age. The ED50 ratios for isoproterenol and acetylcholine were more than 40 and 17, respectively. The maximum relaxation induced by 10(-5) M isoproterenol also decreased significantly in the aortae from the older rats. On the other hand, the ED50 for nitroprusside, nifedipine- and potassium-induced relaxation was not affected by increasing age. These results suggest that ANP-induced relaxation of vascular smooth muscles is reduced with increasing age in rat aortae, rat renal arteries and monkey renal arteries. The mechanisms by which the ANP-induced relaxation decreased in association with the aging process may be quite different from those in acetylcholine-induced and beta adrenoceptor-induced relaxation.     

Arctigenin prevents monocrotaline-induced pulmonary arterial hypertension in rats

The hallmark features of the development of pulmonary arterial hypertension (PAH) include the proliferation of pulmonary vascular smooth muscle cells, oxidative stress, inflammation, and pulmonary artery remodeling. Arctigenin is a bioactive component of Arctium lappa that exerts anti-inflammatory and antiproliferative effects in several diseases; however, its effects on pulmonary arteries are still unclear. This study aimed to investigate the efficacy of arctigenin to prevent PAH. Rats injected with monocrotaline (MCT) progressively developed PAH. Arctigenin treatment (50 mg per kg per day, intra-peritoneally) ameliorated right ventricular systolic pressure and pulmonary arterial remodeling, decreased the expression of inflammatory cytokines, and limited the proliferation of pulmonary vascular smooth muscle cells in lungs. Mechanistically, arctigenin effectively inhibited the MCT-induced elevation of NLRP3, caspase-1, and interleukin 1-beta expression in the lungs. These results indicate that arctigenin ameliorates MCT-induced PAH, at least in part, through exerting its anti-inflammatory, antioxidant, and antiproliferative effects, which inhibit the NLRP3 inflammasome signal pathway in rats.

Arctigenin ameliorates monocrotaline-induced pulmonary arterial hypertension, at least in part, through exerting its anti-inflammatory, antioxidant, and antiproliferative effects, which inhibit the NLRP3 inflammasome signal pathway in rats.     

法舒地尔逆转大鼠重度肺动脉高压实验研究

目的探讨法舒地尔对大鼠重度肺动脉高压及其组织病理改变的影响。方法左肺切除+野百合碱注射建立大鼠重度肺动脉高压模型,雄性SD大鼠60只随机分为5组,A组为对照组,B组为肺动脉高压组,C,D,E组分别为法舒地尔30,50,100mg/(kg.d)干预肺动脉高压组。对各组大鼠进行生存分析,测量平均肺动脉压力、股动脉收缩压、右心室肥厚指数;弹力纤维染色分析肺血管病变;免疫组织化学法检测肺动脉平滑肌细胞凋亡率。结果 C,D,E组生存率明显高于B组,C及D组生存率高于E组(P<0.05);4周后,C,D,E组平均肺动脉压力较B组明显降低,肺动脉中膜肥厚、内膜增生较B组明显减轻,肺动脉平滑肌细胞凋亡率较B组明显升高(P均<0.05);C及D组右心室肥大指数较B组降低(P<0.05);E组动脉收缩压较B组明显下降(P<0.05)。结论中、小剂量法舒地尔可改善重度肺动脉高压大鼠的预后、逆转右心室肥厚及不同类型的肺血管病变。     

组成型一氧化氮合成酶及其酪氨酸磷酸化过程对LPS介入的鼠肺动脉张力的调节作用

目的 研究组成型NO合成酶及其酪氨酸磷酸化过程对LPS介入的鼠肺动脉张力的影响。方法 将取自Sprague-Dawley鼠的肺动脉环悬挂在含有Krebs溶液的游离器官槽中以备作血管反应实验之用。结果 经LPS处理的肺动脉环对去氧肾上腺素的收缩反应明显降低，但此反应的减弱可以被L-NAME，非选择性NO合成酶抑制剂和7-NINA，选择性神经元NO合成酶抑制剂弥补。LPS同时可以降低肺功能对乙酰胆碱的内皮依赖舒张反应，但此减弱由于钒酸钠，选择性酪氨酸磷酸酶抑制剂的存在而缓解，结论 神经元NO合成酶参与了LPS介入的NO过度产生而形成的肺动脉张力降低，而在这个过程中，内皮NO合成酶的催化活性是受损的，但这种损害因触发了另一种通过酪氨酸磷酸化途径的内皮依赖舒张反应而得到补偿。     

Effect of a surgical aortocaval fistula on monocrotaline-induced pulmonary hypertension

OBJECTIVE: Increased pulmonary blood flow is believed to contribute to the development of pulmonary hypertension. We investigated the effect of overcirculation via an aortocaval fistula, on the development of monocrotaline-induced pulmonary hypertension in rats. Monocrotaline was administered 1 wk after the creation of an aortocaval fistula. DESIGN: Randomized, controlled study. SETTING: Research laboratory of an academic institution. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Overcirculation was induced by pneumonectomy and by surgical creation of aortocaval fistula. Pulmonary artery hypertension was induced by administration of monocrotaline. MEASUREMENTS AND MAIN RESULTS: Aortic blood flow, Pao(2), and pulmonary arterial pressure were measured 4 wks later. A blinded investigator quantified pulmonary arterial neointimal formation in small pulmonary arteries. Compared with animals that received monocrotaline and/or underwent pneumonectomy but did not undergo aortocaval fistula, the presence of a surgical aortocaval fistula was associated with increased aortic blood flow (p <.001), increased Pao(2) (p <.001), and lower mean pulmonary arterial pressure (p <.001). In addition, rats with aortocaval fistula had less pulmonary arterial neointimal formation than matched animals without an aortocaval fistula (p =.034). CONCLUSIONS: The presence of a surgical aortocaval fistula attenuates, rather than worsens, the development of monocrotaline-induced pulmonary hypertension in rats.     

Transforming growth factor-beta 1 is decreased in remodeling hypertensive bovine pulmonary arteries.

The development of pulmonary hypertension in hypoxic newborn calves is associated with a complex pattern of increased tropoelastin and type I procollagen synthesis and deposition by smooth muscle cells in large elastic pulmonary arteries compared to normoxic controls. We examined the possibility that transforming growth factor-beta 1 (TGF-beta 1) may be associated with the production of extracellular matrix protein in this model of pulmonary hypertension. Medial smooth muscle cells in both normotensive and hypertensive vessels, as assessed by immunohistochemistry, were the major source of TGF-beta 1. Staining was confined to foci of smooth muscle cells in the outer media and appeared greater in normotensive than hypertensive vessels. Consistent with the immunohistochemistry, a progressive, age-dependent increase in normotensive pulmonary artery TGF-beta 1 mRNA was observed after birth, whereas TGF-beta 1 mRNA remained at low, basal levels in hypertensive, remodeling pulmonary arteries. These observations suggest that local expression of TGF-beta 1 is not associated with increased extracellular matrix protein synthesis in this model of hypoxic pulmonary hypertension.     

Magnesium aspartate hydrochloride attenuates monocrotaline-induced pulmonary artery hypertension in rats

1. The effect of oral magnesium aspartate hydrochloride on monocrotaline (MCT)-induced pulmonary arterial hypertension was evaluated in rats. 2. A single subcutaneous injection of MCT, a pyrrolizidine alkaloid of plant origin, induces significant morphological changes in pulmonary vessels, pulmonary arterial hypertension and right ventricular hypertrophy in rats by 3 weeks. 3. Two groups of rats (Mg2+ control and Mg2+ + MCT) were started on oral Mg2+ (15.4 g/l magnesium aspartate hydrochloride dissolved in deionized water) 2 weeks before the MCT injection. The rest were given deionized water. At the start of the experiment, the control groups (deionized water and Mg2+) were given normal saline subcutaneously; the other groups (deionized water and Mg2+) were given MCT (60 mg/kg) subcutaneously. 4. Pulmonary artery pressure, right ventricular hypertrophy, lung pathology, organ weights and serum electrolytes were assessed 3 weeks after a single subcutaneous injection of MCT. Seventy-five per cent of the rats treated with MCT and oral Mg2+ (12 out of 16) showed significant reduction in pulmonary arterial hypertension, arterial pathology and right ventricular hypertrophy. 5. Our data indicate that Mg2+ attenuates experimentally induced pulmonary hypertension, possibly either by modulating the intracellular Ca2+ level and/or by directly affecting the pulmonary endothelial cell-smooth muscle cell complex involved in metabolism and maintenance of pulmonary vascular resistance.     

Angiotensin converting enzyme expression is increased in small pulmonary arteries of rats with hypoxia-induced pulmonary hypertension.

Previous studies suggest that while lung angiotensin converting enzyme (ACE) activity is reduced during chronic hypoxia, inhibitors of ACE attenuate hypoxic pulmonary hypertension. In an attempt to explain this paradox we investigated the possibility that whole lung ACE activity may not reflect local pulmonary vascular ACE expression. The experimental approach combined in vivo hemodynamic studies in control and chronically hypoxic rats, measurement of whole lung ACE activity, and evaluation of local pulmonary vascular ACE expression by in situ hybridization and immunohistochemistry. Total lung ACE activity was reduced to 50% of control activity by 5 d of hypoxia and remained low for the duration of the study. Immunohistochemistry showed a marked reduction of ACE staining in alveolar capillary endothelium. However, an increase in ACE staining was observed in the walls of small newly muscularized pulmonary arteries at the level of alveolar ducts and walls. In situ hybridization studies showed increased signal for ACE mRNA in the same vessels. Inhibition of ACE by captopril during chronic hypoxia attenuated pulmonary hypertension and markedly reduced distal muscularization of small pulmonary arteries. In addition, we demonstrated marked longitudinal variation in ACE expression along the normal pulmonary vasculature with the highest levels found in small muscular arteries associated with terminal and respiratory bronchioles. We conclude that local ACE expression is increased in the walls of small pulmonary arteries during the development of hypoxic pulmonary hypertension, despite a generalized reduction in alveolar capillary ACE expression, and we speculate that local arteriolar ACE may play a role in the vascular remodeling associated with pulmonary hypertension.     

Antagonism of acetylcholine-mediated relaxation of rabbit pulmonary arteries by phorbol myristate acetate

We studied the effect of 4-phorbol 12-myristate 13-acetate (PMA) on endothelium-dependent relaxation of rabbit isolated lobar pulmonary arteries contracted with phenylephrine. After full development of relaxation in response to 1.0 microM acetylcholine, addition of 10.0 nM PMA reversed relaxation rapidly and completely. This effect of PMA on acetylcholine-induced relaxation was unchanged when catalase was included in the medium. In separate groups of experiments, lobar pulmonary arteries were preincubated with 10.0 nM PMA for 20 min and then challenged with acetylcholine without washout of PMA. In these experiments PMA did not block completely the relaxation in response to addition of 1.0 microM acetylcholine. Log-concentration response curves for 0.01 to 31.6 microM acetylcholine vs. relaxation as percentage of phenylephrine-induced tone exhibited rightward shifts and depression of maxima after pretreatment with PMA. The EC50 for acetylcholine-induced relaxation was increased from 57 +/- 9.0 to 377 +/- 6.30 nM (values are mean +/- S.E.). Relaxation of lobar pulmonary arteries induced by 10.0 nM A23187 was much less sensitive to treatment with PMA than relaxation induced by acetylcholine. At least for the low concentration of PMA used here, these data are consistent with the following: 1) PMA blocks acetylcholine-induced relaxation by disrupting the link between acetylcholine receptor occupancy and the formation or release of the endothelium-derived relaxing factor, 2) PMA does not directly block the relaxant action of endothelium-derived relaxing factor on vascular smooth muscle and 3) the effect of PMA on acetylcholine-induced relaxation is not mediated by hydrogen peroxide or derived oxygen radicals.     

Disruption of vascular Ca2+-activated chloride currents lowers blood pressure

High blood pressure is the leading risk factor for death worldwide. One of the hallmarks is a rise of peripheral vascular resistance, which largely depends on arteriole tone. Ca²⁺-activated chloride currents (CaCCs) in vascular smooth muscle cells (VSMCs) are candidates for increasing vascular contractility. We analyzed the vascular tree and identified substantial CaCCs in VSMCs of the aorta and carotid arteries. CaCCs were small or absent in VSMCs of medium-sized vessels such as mesenteric arteries and larger retinal arterioles. In small vessels of the retina, brain, and skeletal muscle, where contractile intermediate cells or pericytes gradually replace VSMCs, CaCCs were particularly large. Targeted disruption of the calcium-activated chloride channel TMEM16A, also known as ANO1, in VSMCs, intermediate cells, and pericytes eliminated CaCCs in all vessels studied. Mice lacking vascular TMEM16A had lower systemic blood pressure and a decreased hypertensive response following vasoconstrictor treatment. There was no difference in contractility of medium-sized mesenteric arteries; however, responsiveness of the aorta and small retinal arterioles to the vasoconstriction-inducing drug U46619 was reduced. TMEM16A also was required for peripheral blood vessel contractility, as the response to U46619 was attenuated in isolated perfused hind limbs from mutant mice. Out data suggest that TMEM16A plays a general role in arteriolar and capillary blood flow and is a promising target for the treatment of hypertension.     

Tocilizumab对肺动脉高压大鼠IL-6及survivin的影响

目的观察tocilizumab对肺动脉高压大鼠白细胞介素-6（IL-6）和survivin的表达水平的影响。方法通过腹腔注射野百合碱诱导建立肺动脉高压大鼠模型,观察tocilizumab对肺动脉高压大鼠IL-6和survivin的表达水平的影响。结果 Tocilizumab干预组大鼠和空白对照组大鼠mPAP、IL-6和survivin含量明显低于实验对照组,P〈0.05。Tocilizumab干预组肺动脉血管内膜轻度水肿,血管壁轻度增厚。IL-6和survivin在实验对照组大鼠肺组织和血清中表达强烈,在tocilizumab干预组大鼠肺组织少量表达,而空白对照组大鼠肺组织不表达。结论 Tocilizumab可有效抑制野百合碱可诱导肺动脉高压大鼠IL-6和survivin的表达,抑制肺动脉高压的发生。     

移植骨髓间充质干细胞预防野百合碱诱导的肺动脉高压

背景：干细胞移植治疗肺动脉高压有一定疗效。目的：观察骨髓间充质干细胞移植治疗肺动脉高压的效果及并探讨其作用机制。方法：采用密度梯度离心法体外培养、纯化、扩增获得大鼠骨髓间充质干细胞,经荧光染料标记后备用。大鼠皮下注射野百合碱建立肺动脉高压模型,建模后1周将大鼠随机分为3组,干细胞移植组和肺动脉高压组大鼠皮下注射野百合碱建立肺动脉高压模型,1周后干细胞组大鼠经舌下静脉注射骨髓间充质干细胞悬液,肺动脉高压组注射等量不含干细胞的培养液,对照组皮下注射等量生理盐水。结果与结论：移植后2周,与野百合碱诱导的肺动脉高压大鼠相比干细胞移植组血流动力学参数及右心室与体质量之比明显改善（P〈0．05）;肺血管重构程度减轻（P〈0．05）。荧光显微镜下发现干细胞组移植的骨髓间充质干细胞在大鼠体内能存活至少2周,部分干细胞能转化为血管平滑肌细胞。说明静脉移植骨髓间充质干细胞能明显改善野百合碱造成的肺动脉高压大鼠肺血管和右心室结构的损伤。     

白介素4通过调节巨噬细胞分化促进野百合碱诱导大鼠肺动脉高压模型的肺血管重塑

目的探讨大鼠肺动脉高压模型中白介素-4(IL-4)对巨噬细胞分化和肺血管重塑的影响。方法利用野百合碱(MCT)腹腔注射构建大鼠肺动脉高压模型,以超声心动图及病理改变作为建模成功的观察指标。采用Elisa及荧光定量PCR(qRT-PCR)检测各组血液中IL-4的表达。利用IL-4中和抗体静脉注射肺动脉高压大鼠,抑制体内IL-4的作用,并通过超声心动图及HE染色观察肺动脉高压情况。结果与对照组比较,肺动脉高压组大鼠血液中IL-4的表达(4.01±0.18 vs.9.08±0.25)明显上调(P0.01),大鼠右心室压力(58.00±2.84 vs.20.13±1.89)明显上调(P0.01),且肺血管重塑明显增加。与肺动脉高压组和IgG组比较,IL-4中和抗体组大鼠右心室压力[(42.77±2.04)vs.(58.00±2.84)vs.(57.62±1.44)]明显降低(P0.01),且肺血管重塑明显降低。与肺动脉高压组和IgG组比较,IL-4中和抗体组大鼠肺组织中CD206mRNA表达量[(2.88±0.17)×10-3vs.(4.22±0.08)×10-3vs.(4.36±0.26)×10-3]明显降低(P0.01)。结论肺动脉高压后,上调的IL-4可以促进巨噬细胞向Ⅱ型巨噬细胞分化,进而调节肺动脉的血管重塑过程。     

缬沙坦减轻肺高压大鼠肺血管平滑肌细胞增生的研究

目的:探讨缬沙坦降压和对肺高压大鼠肺血管平滑肌细胞增生的影响。方法:对分流组及治疗组大鼠行腹主动脉-下腔静脉分流术,治疗组以缬沙坦40mg/(kg·d)灌胃。术后6周和11周分别测定肺动脉平均压(PAMP)、右心室(RV)/左心室+室间隔(LV+S)比值,观察肺血管壁的变化。结果:治疗组大鼠术后6周和11周PAMP、RV/LV+S及肺血管平滑肌细胞增生程度均比分流组为轻。结论:缬沙坦有降低肺高压大鼠肺动脉压力,减轻肺血管平滑肌细胞增生的作用。