慢性低氧对大鼠左右心室的功能及TRPC亚家族表达的影响

目的：探讨慢性低氧3周对大鼠左右心室的影响以及规范性瞬时感受器电位亚家族（TRPC）在慢性低氧诱导的右心室心肌肥厚中的表达。方法：将SD雄性大鼠48只随机分为对照组（CON组）和慢性低氧肺动脉高压模型组（CH组）（n=24）,CH组将大鼠置于连续的慢性低氧（10％±0．2％）环境饲养三周以诱导大鼠发生心肌肥厚。通过左、右心室插管法测定右心室内压（RVSP）、左心室内压（LVSP）、心率（HR）、平均体循环动脉压（mSAP）、左、右心室内压力最大上升速率（＋dp／dtmax）、最大下降速率（-dp／dkmax）、右心肥大指数（RVMI）、左心肥大指数（LVMI）;HE染色观察左、右心室心肌组织切片;通过SYBR Green荧光定量PCR法检测CON组、CH组大鼠的肥厚侧心室心肌组织编码TRPC 1／3／4／5／6／7的rnRNA表达;结合real-time RT-PCR结果对mRNA表达有显著变化的TRPC亚型通过免疫印迹法检测相应蛋白的表达。结果：与CON组相比：CH组的RVSP、RVMI、右心室±dp／dtmax显著增高（P〈0．01）,LVSP、左心室±dp／dmax无显著变化,LVMI显著降低（P〈0．01）;CH组右心室心肌细胞显著增粗（P〈0．01）,细胞内肌原纤维数量增多,心肌纤维排列紊乱,细胞核深染,形状不整;左心室心肌纤维无明显改变;CH组编码TRPCI的mRNA和蛋白显著增高（P〈0．05）,而编码其余TRPC亚型的mRNA无显著变化。结论：慢性低氧3周可特异性诱导sD大鼠产生右心室心肌肥厚,上调了编码右心室心肌细胞TRPCI通道蛋白的mRNA和蛋白的表达,TRPCI可能参与了心肌肥厚的发生发展。     

Ca~(2+)信号调控细胞死亡的亚细胞和分子机制

Ca2+在细胞死亡过程中起至关重要的作用。胞浆和/或线粒体(MT)内Ca2+超载不但是多种原因、多种方式细胞死亡的起始因素,也可通过激活蛋白酶、核酸酶、磷脂酶等酶,直接或间接通过与Bcl-2家族蛋白等重要调节因素的相互作用,全程参与死亡生化反应。内质网(ER)释放Ca2+与MT、溶酶体(LS)、细胞核相互作用,激活多种细胞死亡信号转导通路,导致细胞凋亡、坏死和自噬性细胞死亡。本文重点介绍Ca2+信号在亚细胞和分子水平调控细胞死亡的机制研究方面的最新进展。     

肺高压大鼠肺动脉平滑肌细胞薄荷醇引起的胞浆游离Ca~(2+)浓度增加幅度减低

本文通过观察正常(control,CON)、慢性低氧(chronic hypoxia,CH)和野百合碱(monocrotaline,MCT)预处理肺高压大鼠肺动脉平滑肌细胞(pulmonary arterial smooth muscle cells,PASMCs)中,瞬时感受器电位M8(transient receptor potential melastatin8,TRPM8)通道特异激动剂薄荷醇(menthol,MT)引起的胞浆游离钙浓度([Ca2+]i)变化,探讨TRPM8通道在肺高压发病过程中的作用。大鼠处于CH环境或一次性腹腔注射MCT制备肺高压大鼠模型;原代培养CON和肺高压大鼠PASMCs,观察MT激动TRPM8通道引起的PASMCs[Ca2+]i变化,以及TRPM8通道特异阻断剂N-(4-叔-丁基苯基)-4-(3-氯吡啶-2-基)哌嗪-1-甲酰胺[N-(4-tert-butylphenyl)-4-(3-chloropyridin-2-yl)piperazine-1-carboxamide,BCTC]对MT引起[Ca2+]i变化作用的抑制效应;免疫组化检测TRPM8的细胞定位。结果显示,在2 mmol/L Ca2+和无Ca2+台氏液中,MT都可以引起CON组PASMCs的[Ca2+]i增高,且这两种增高作用均可以被BCTC阻断;在2 mmol/L Ca2+和无Ca2+台氏液中,与CON组相比,CH组和MCT组MT引起PASMCs的[Ca2+]i增高幅度均显著减小。免疫组化细胞定位实验显示,PASMCs除胞核外其余部分均有TRPM8棕黄色阳性表达。以上结果提示,PASMCs上的TRPM8通道既存在于胞膜,也存在于肌浆网;CH和MCT预处理可以分别减少PASMCs上TRPM8通道介导的Ca2+内流与Ca2+释放。     

短期模拟失重可增强大鼠脑动脉平滑肌细胞L-型Ca~(2+)通道对血管紧张素Ⅱ的反应性

已有研究表明模拟失重可引起大鼠脑动脉发生区域特异性变化,其中Ca2+通道和肾素-血管紧张素系统(renin-angio-tensin system,RAS)可能发挥着重要的作用。本研究旨在探讨血管紧张素Ⅱ(angiotensin Ⅱ,Ang Ⅱ)对短期模拟失重大鼠脑基底动脉血管平滑肌细胞(vascular smooth muscle cells,VSMCs)L-型Ca2+通道(L-type calcium channel,CaL)功能的影响。模拟失重(尾部悬吊)3d后,用木瓜蛋白酶法分离大鼠脑基底动脉VSMCs。采用全细胞膜片钳技术,以Ba2+作为载流子,测定CaL电流密度,然后观察Ang Ⅱ对该电流的影响。结果显示,模拟失重3d对大鼠脑基底动脉VSMCs的膜电容和接入电阻无明显影响,但可致VSMCs的CaL电流密度显著增加。不过,模拟失重对CaL的电压激活特性和稳态激活曲线亦无明显影响。对照组和模拟失重组大鼠脑基底动脉VSMCs的CaL电流密度在给予Ang Ⅱ处理后均显著增加,且模拟失重组的增加幅度显著大于对照组。以上结果提示,3d短期模拟失重即可引起大鼠脑动脉VSMCs的CaL发生适应性改变,且可导致其对...     

Ca~(2+)转运通路对金雀异黄酮舒张大鼠脑血管作用的影响

目的:研究Ca2+转运通路对金雀异黄酮舒张大鼠脑血管作用的影响。方法:75只大鼠被随机分为3组,分别经由二甲亚砜、金雀异黄酮和酪氨酸磷酸化抑制剂A47处理基底动脉及Willis环血管。每组大鼠进一步划分成5个亚组,每个亚组用不同浓度的细胞外Ca2+处理,分为:0、0.6、1.2、1.8和3.6 m M Ca2+组。5-羟色胺诱导血管收缩。测定大鼠基底动脉管壁厚度与官腔周长的比值;荧光成像分析法测定血管平滑肌细胞细胞内Ca2+浓度;免疫印迹分析检测肌球蛋白轻链激酶(MLCK),蛋白质磷酸酶催化亚基1(PP1),肌凝蛋白磷酸酶目标亚基1(MYPT1)的表达来测定血管平滑肌细胞Ca2+敏感性。结果:金雀异黄酮和酪氨酸磷酸化抑制剂A47显著降低大鼠基底动脉管壁厚度与官腔周长的比值(P0.01),Ca2+内流(P0.01,P0.05)及MLCK的表达(P0.01);增加PP1和MYPT1的表达(P0.01)。细胞外Ca2+与金雀异黄酮及酪氨酸磷酸化抑制剂A47有协同效应。硝苯地平和毒胡萝卜素可废除该效应。结论:低细胞外Ca2+水平增强了金雀异黄酮和酪氨酸磷酸化抑制剂A47的血管舒张作用。L型电压门控Ca2+通道(L-VGCC)和肌浆网Ca2+库(SR)参与交互效应。     

介质中不同Ca~(2+)浓度对五种榕树幼苗钙含量的影响

选择高榕(Ficusaltissima)、木瓜榕(F.auriculata)、聚果榕(F.racemosa)、鸡嗉子榕(F.semicorda ta)以及对叶榕(F.hispida)5种榕树,对其幼苗进行不同Ca2+(CaCl2)浓度下的水培实验,结果表明,5种幼苗钙含量随介质Ca2+浓度的增加而增加,增加趋势大致相同。高Ca2+浓度下(10mmol/L)幼苗地上部的钙含量为低Ca2+浓度下(0.05mmol/L)的1.51～1.63倍。5种榕树幼苗钙含量随培养液Ca2+浓度变化的Yadj值的多重比较结果显示,对叶榕钙含量显著高于其他四种(P<0 01),高榕则显著低于其他四种(P<0 01),木瓜榕、聚果榕、鸡嗉子榕之间的差异不显著。不同榕树幼苗地上部分钙含量受介质钙浓度影响,但可能主要决定于基因型的差异,表明榕属植物富钙基因的存在,这为高钙榕树植物资源开发提供初步的理论依据。     

大鼠肺动脉平滑肌培养细胞内Ca~(2+)反应的多样性

用Ｃａ２＋荧光色素Ｆｌｏｕ－３／ＡＭ负荷原代培养的大鼠肺动脉平滑肌细胞,在共聚焦激光显微镜下观察细胞内Ｃａ２＋对各种缩血管物质反应的非均一性。实验结果提示：各种Ｃａ２＋通道的反应与细胞培养时间相关。８０％以上的Ｃａ２＋贮库具有ＣＩＣＲＣａ２＋通道,在肺血管管平滑肌细胞可能存在一种只具有ＣＩＣＲ通道的Ｃａ２＋贮库,ＣＩＣＲ的Ｃａ２＋释放作用强于ＩＣＲＣａ２＋通道     

库容性Ca2+内流参与ACh诱导的大鼠远端结肠平滑肌收缩

应用生物换能技术和Ca^2＋通道特异性阻断剂观察并记录大鼠离体远端结肠平滑肌收缩张力的变化,分析库容性Ca^2＋内流（capacitative Ca^2＋ entry,CCE）是否与ACh诱导的离体远端结肠平滑肌收缩反应有关。结果表明,以无钙的Krebs液灌流或应用EGTA螯合细胞外Ca^2＋后,高K^＋及ACh引起的远端结肠平滑肌收缩几乎完全消失。电压操纵性Ca^2＋通道阻断剂verapamil也能减弱高K^＋及ACh引起的远端结肠平滑肌收缩,其减弱的程度分别为74％和41％。在无钙的Krebs液中,5μmol／LACh可引起离体肠管瞬时性收缩,这是由肌质网（sarcoplasmic reticulum,SR）释放钙所致：然后加入10μmol／L阿托品（atropine）,并在此基础上恢复细胞外Ca^2＋（2．5mmol／L）,结肠平滑肌则出现持续性收缩,待收缩反应达峰值时,加入5μmol／L verapamil,收缩无明显变化,且该收缩反应对钙库操纵性通道（store-operated Ca^2＋ channel,socc）阻断剂La^3＋敏感,20,50和100μmol／L的La^3＋使上述收缩张力分别降低15％,23％和36％,且呈浓度依赖性,但对Cd^2＋不敏感。研究结果提示,细胞外Ca^2＋内流对高K^＋及ACh介导的离体远端结肠平滑肌持续性收缩是必需的,由ACh诱导的远端结肠平滑肌收缩至少包括SR释放钙引起的短暂性收缩及受体操纵性Ca^2＋通道（receptor-operated Ca^2＋ channel,ROCC）、电压操纵性Ca^2＋通道（voltage-operated Ca^2＋ channel,VOCC）和CCE介导的胞外Ca^2＋ 内流等途径。这将从通道水平进一步分析消化管平滑肌收缩的机制和特征,亦将为预防和控制因胃肠动力紊乱所致的消化管疾病寻求有针对性的药物干预和治疗提供理论依据。     

pH改变对心肌细胞内Ca~(2 )浓度和细胞长度的影响

目的 :探讨细胞内 pH(pHi)改变对心肌细胞内Ca2 浓度 ([Ca2 ]i)和细胞长度的影响。方法 :心肌细胞内分别灌注 2 0mmol/L丙酸钠和 15mmol/LNH4Cl,建立细胞内酸碱中毒模型。荧光指示剂indo 1和SNARF 1载入大鼠心肌细胞内 ,用荧光显微镜同时测定心肌 [Ca2 ]i、pHi 和细胞长度。结果 :细胞内酸中毒早期 ,收缩期和舒张期[Ca2 ]i 轻度增加 ,细胞缩短 (CS)降低 ,细胞长度增加 ,心肌纤维对Ca2 的敏感性和CS/ [Ca2 ]i 降低 (P <0 .0 1) ;碱中毒时 ,收缩期和舒张期 [Ca2 ]i 均较对照组降低 ,CS增加 ,细胞长度变短 ,心肌纤维对Ca2 的敏感性和CS/[Ca2 ]i 增加 (P <0 .0 1)。结论 :酸中毒早期 [Ca2 ]i 和细胞长度增加 ,碱中毒时 [Ca2 ]i和细胞长度降低。酸、碱中毒对Ca2 敏感性的影响并非线性关系 ,即单位 pHi变化时酸中毒对敏感性的影响较碱中毒小     

大黄素影响巨噬细胞升高[Ca~(2+)]_i和释放TNF-a的作用特征

为了研究大黄素(emodin)对正常的和细菌脂多糖(LPS)刺激的大鼠腹腔巨噬细胞(PM准)释放肿瘤坏死因子琢(TNF-琢)和升高[Ca2+]i的影响,应用L929细胞系和MTT法检测TNF-琢量,同时用激光共焦扫描显微术检测单细胞[Ca2+]i变化动力学。结果显示大黄素能轻度促进正常PM准释放TNF-琢,并发现大黄素诱发PM准[Ca2+]i变化呈振荡波模式。大黄素显著抑制LPS刺激PM准过度释放TNF-琢和升高[Ca2+]i,10-5mol/L大黄素抑制了10mg/LLPS刺激的TNF-琢峰值的50%和[Ca2+]i峰值的68%。LPS诱发PM准[Ca2+]i变化呈现高幅值的“平台期”,大黄素使之转变为低幅值的波动变化。以上结果说明,大黄素对PM准释放TNF-琢和升高[Ca2+]i表现出的双向调节作用之间有一定的相关性,大黄素对LPS诱发的[Ca2+]i升高的调制,可能是抑制LPS刺激PM准释放TNF-琢的信号传导通路中的重要环节。     

NDUFA4L2 in smooth muscle promotes vascular remodeling in hypoxic pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by a progressive increase in pulmonary vascular resistance and obliterative pulmonary vascular remodelling (PVR). The imbalance between the proliferation and apoptosis of pulmonary artery smooth muscle cells (PASMCs) is an important cause of PVR leading to PAH. Mitochondria play a key role in the production of hypoxia-induced pulmonary hypertension (HPH). However, there are still many issues worth studying in depth. In this study, we demonstrated that NADH dehydrogenase (ubiquinone) 1 alpha subcomplex 4 like 2 (NDUFA4L2) was a proliferation factor and increased in vivo and in vitro through various molecular biology experiments. HIF-1α was an upstream target of NDUFA4L2. The plasma levels of 4-hydroxynonene (4-HNE) were increased both in PAH patients and hypoxic PAH model rats. Knockdown of NDUFA4L2 decreased the levels of malondialdehyde (MDA) and 4-HNE in human PASMCs in hypoxia. Elevated MDA and 4-HNE levels might be associated with excessive ROS generation and increased expression of 5-lipoxygenase (5-LO) in hypoxia, but this effect was blocked by siNDUFA4L2. Further research found that p38-5-LO was a downstream signalling pathway of PASMCs proliferation induced by NDUFA4L2. Up-regulated NDUFA4L2 plays a critical role in the development of HPH, which mediates ROS production and proliferation of PASMCs, suggesting NDUFA4L2 as a potential new therapeutic target for PAH.     

NAADP-induced intracellular calcium ion is mediated by the TPCs (two-pore channels) in hypoxia-induced pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a form of obstructive vascular disease. Chronic hypoxic exposure leads to excessive proliferation of pulmonary arterial smooth muscle cells and pulmonary arterial endothelial cells. This condition can potentially be aggravated by [Ca²⁺] _i mobilization. In the present study, hypoxia exposure of rat's model was established. Two-pore segment channels (TPCs) silencing was achieved in rats' models by injecting Lsh-TPC1 or Lsh-TPC2. The effects of TPC1/2 silencing on PAH were evaluated by H&E staining detecting pulmonary artery wall thickness and ELISA assay kit detecting NAADP concentrations in lung tissues. TPC1/2 silencing was achieved in PASMCs and PAECs, and cell proliferation was detected by MTT and BrdU incorporation assays. As the results shown, NAADP-activated [Ca²⁺]_i shows to be mediated via two-pore segment channels (TPCs) in PASMCs, with TPC1 being the dominant subtype. NAADP generation and TPC1/2 mRNA and protein levels were elevated in the hypoxia-induced rat PAH model; NAADP was positively correlated with TPC1 and TPC2 expression, respectively. In vivo, Lsh-TPC1 or Lsh-TPC2 infection significantly improved the mean pulmonary artery pressure and PAH morphology. In vitro, TPC1 silencing inhibited NAADP-AM-induced PASMC proliferation and [Ca²⁺]_i in PASMCs, whereas TPC2 silencing had minor effects during this process; TPC2 silencing attenuated NAADP-AM- induced [Ca²⁺]_i and ECM in endothelial cells, whereas TPC1 silencing barely ensued any physiological changes. In conclusion, TPC1/2 might provide a unifying mechanism within pulmonary arterial hypertension, which can potentially be regarded as a therapeutic target.     

Increased rhythmicity in hypertensive arterial smooth muscle is linked to transient receptor potential canonical channels

Vasomotion describes oscillations of arterial vascular tone due to synchronized changes of intracellular calcium concentrations. Since increased calcium influx into vascular smooth muscle cells from spontaneously hypertensive rats (SHR) has been associated with variances of transient receptor potential canonical (TRPC) channels, in the present study we tested the hypothesis that increased vasomotion in hypertension is directly linked to increased TRPC expression. Using a small vessel myograph we observed significantly increased norepinephrine‐induced vasomotion in mesenteric arterioles from SHR compared to normotensive Wistar–Kyoto (WKY) rats. Using immunoblottings we obtained significantly increased expression of TRPC1, TRPC3 and TRPC5 in mesenteric arterioles from SHR compared to WKY, whereas TRPC4 and TRPC6 showed no differences. Norepinephrine‐induced vasomotion from SHR was significantly reduced in the presence of verapamil, SKF96365, 2‐aminoethoxydiphenylborane (2‐APB) or gadolinium. Pre‐incubation of mesenteric arterioles with anti‐TRPC1 and anti‐TRPC3 antibodies significantly reduced norepinephrine‐induced vasomotion and calcium influx. Control experiments with pre‐incubation of TRPC antibodies plus their respective antigenic peptide or in the presence of anti‐β‐actin antibodies or random immunoglobulins not related to TRPC channels showed no inhibitory effects of norepinephrine‐induced vasomotion and calcium influx. Administration of candesartan or telmisartan, but not amlodipine to SHR for 16 weeks significantly reduced either the expression of TRPC1, TRPC3 and TRPC5 as well as norepinephrine‐induced vasomotion in mesenteric arterioles. In conclusion we gave experimental evidence that the increased TRPC1, TRPC3 and TRPC5 expression in mesenteric arterioles from SHR causes increased vasomotion in hypertension.     

Compensatory roles of Protein Related to DAN and Cerberus (PRDC) decrease in pulmonary arterial hypertension

Bone morphogenetic protein (BMP) signaling is commonly suppressed in patients with pulmonary arterial hypertension (PAH), but the compensatory mechanism of BMP signaling suppression is incompletely elucidated. This study aimed to investigate the role of PRDC, an antagonist of BMPs, in PAH and the underlying mechanism. Human lungs were collected and rat PAH was induced (monocrotaline, 60 mg/kg). BMP cascade and PRDC were detected in lungs and distal pulmonary artery smooth muscle cells (dPASMCs). In vitro cell experiments and in vivo supplementation of PRDC in hypertensive rats were subsequently performed. PRDC and BMP cascade all decreased in human and rat hypertensive lungs. Cell experiments confirmed that BMP2/4 inhibited dPASMCs proliferation by increasing cell cycle inhibitors (p21, p27), prevented dPASMCs migration by down-regulating MMP2/9 and up-regulating TIMP1/2 expression, and promoted dPASMCs apoptosis by up-regulating Bax, caspase3/9 and down-regulating Bcl-2 expression, as well as enhancing caspase3/7 activity, while, PRDC reversed the effects of BMP2/4 on dPASMCs proliferation, migration and apoptosis. In vivo trial found that PRDC supplementation deteriorated rat PAH in terms of pulmonary hemodynamics, vasculopathies and right ventricle hypertrophy. Taken together, compensatory decrease of PRDC in hypertensive lungs theoretically slow down the natural course of PAH, suggesting its therapeutic potential in PAH.     

苹果多酚对野百合碱诱导的肺动脉高压大鼠肺血管重构的作用和机制

目的:探讨苹果多酚抑制肺动脉高压大鼠肺动脉血管重构的作用及其机制。方法:雄性SD大鼠随机分为对照组(Con),野百合碱(MCT)组,苹果多酚(APP)组,野百合碱+苹果多酚(MCT+APP)组,每组9只。Con组:每天皮下注射1ml生理盐水;APP组:隔天按20mg/kg的剂量腹腔注射苹果多酚;MCT组:按60mg/kg剂量一次性皮下注射MCT;MCT+APP组:一次性皮下注射60mg/kg剂量MCT,隔天按20mg/kg剂量腹腔注射APP,所有处理持续3周。建模完成后,检测各组大鼠平均肺动脉压(mPAP),肺血管阻力(PVR),右心室肥厚指数(RVHI),肺动脉血管环外周长比值(WT%),肺小血管管壁面积和管总面积比值(WA%)。检测肺组织中的白细胞介素1(IL-1),白细胞介素6(IL-6),肿瘤坏死因子α(TNF-α),环氧化酶2(COX-2),髓过氧化物酶(MPO)等炎症通路相关指标,及肺动脉平滑肌细胞内Ca2+和内皮细胞eNOS,NO含量。结果:MCT组大鼠与对照组比较,在动物水平的指标mPAP、PVR、RVHI、WA%、WT%和肺动脉组织内IL-1,IL-6,TNF-α,COX-2,MPO表达量以及肺动脉平滑肌细胞内的Ca2+浓度明显升高(P<0.05),而内皮细胞中的eNOS,NO含量明显下降(P<0.05);苹果多酚治疗组与MCT组大鼠相比上述情况得到改善,其中COX-2和Ca2+指标明显下降,且具有统计学意义(P<0.05)。结论:苹果多酚可通过抑制MCT引起的肺组织内IL-1,IL-6,TNF-α,COX-2升高和肺动脉平滑肌细胞内Ca2+升高以及内皮细胞中eNOS,NO降低,抑制平滑肌细胞增殖,逆转肺血管重构,缓解肺动脉高压。     

脂肪干细胞移植对野百合碱诱发的肺动脉高压大鼠肺动脉压的量效和时效作用

目的探索脂肪干细胞（ADSC）移植治疗野百合碱（MCT）诱导的肺动脉高压（PAH）大鼠的适宜细胞数和干预时间。 方法（1）MCT的建模时效和量效：雄性SD大鼠48只分为正常对照组,20 mg/kg、30 mg/kg、40 mg/kg MCT组分别予腹腔注射生理盐水、MCT 20 mg/kg、30 mg/kg、40 mg/kg,4和8周后,右心室插管法检测平均肺动脉压（mPAP）,称重法计算右心室肥厚指数（RVHI）。（2）ADSC的治疗量效作用：雄性SD大鼠分别予腹腔注射MCT（30只）和生理盐水（30只）,1周后通过颈静脉注射分别移植0.5×10⁶、1.0×10⁶、3.0×10⁶、5.0×10⁶ADSC,其他组予等量生理盐水。移植3周后检测mPAP和RVHI。（3）ADSC的治疗时效作用：雄性SD大鼠30只,分别注射40 mg/kg MCT（24只）和生理盐水（6只）。MCT腹腔注射1 d,1、2周后分别移植1.0×10⁶个ADSC。MCT注射4周后检测mPAP和RVHI。多组间比较采用单因素或双因素方差分析,两两比较采用LSD检验。 结果（1）腹腔注射4周后,30 mg/ kg或40 mg/kg MCT组mPAP和RVHI均升高[mPAP值（24.89±3.31）mmHg,（27.19±2.11）mmHg比（15.80±0.42）mmHg,差异有统计学意义（P均< 0.05）;RVHI值0.42±0.06,0.47±0.04比0.25±0.02,差异有统计学意义（P均< 0.05）]。8周后,20 mg/kg或30 mg/ kg MCT组mPAP和RVHI均恢复正常,而40 mg/kg MCT组大鼠全部死亡。（2）40 mg/ kg MCT诱导的PAH大鼠mPAP和RVHI均升高。移植1.0×10⁶个ADSC可降低PAH大鼠的mPAP[（17.24±0.66）mmHg比（27.19±1.73）mmHg,P < 0.05]。移植0.5×10⁶、3.0×10⁶、5.0× 10⁶个ADSC不能降低PAH大鼠的mPAP和RVHI。（3）MCT腹腔注射1周和2周后,移植1.0×10⁶个ADSC可降低PAH大鼠的mPAP。 结论40 mg/kg MCT造模4周可建立稳定的PAH大鼠模型;造模1或2周后移植1.0×10⁶个ADSC能有效降低PAH大鼠的mPAP。     

Effects of chronic hypoxia on Ca(2+) stores and capacitative Ca(2+) entry in human neuroblastoma (SH-SY5Y) cells.

Microfluorimetric measurements of intracellular calcium ion concentration [Ca(2+)](i) were employed to examine the effects of chronic hypoxia (2.5% O(2), 24 h) on Ca(2+) stores and capacitative Ca(2+) entry in human neuroblastoma (SH-SY5Y) cells. Activation of muscarinic receptors evoked rises in [Ca(2+)](i) which were enhanced in chronically hypoxic cells. Transient rises of [Ca(2+)](i) evoked in Ca(2+)-free solutions were greater and decayed more slowly following exposure to chronic hypoxia. In control cells, these transient rises of [Ca(2+)](i) were also enhanced and slowed by removal of external Na(+), whereas the same manoeuvre did not affect responses in chronically hypoxic cells. Capacitative Ca(2+) entry, observed when re-applying Ca(2+) following depletion of intracellular stores, was suppressed in chronically hypoxic cells. Western blots revealed that presenilin-1 levels were unaffected by chronic hypoxia. Exposure of cells to amyloid beta peptide (1-40) also increased transient [Ca(2+)](i) rises, but did not mimic any other effects of chronic hypoxia. Our results indicate that chronic hypoxia causes increased filling of intracellular Ca(2+) stores, suppressed expression or activity of Na(+)/Ca(2+) exchange and reduced capacitative Ca(2+) entry. These effects are not attributable to increased amyloid beta peptide or presenilin-1 levels, but are likely to be important in adaptive cellular remodelling in response to prolonged hypoxic or ischemic episodes.