低氧诱导因子1在低氧致肺动脉平滑肌细胞增殖中的作用

目的: 探讨低氧对肺动脉平滑肌细胞(PASMC)增殖和凋亡的影响,以及HIF-1α、P-ERK1/2、iNOS蛋白表达变化在其中的作用与意义。方法: 体外培养大鼠PASMC，设计常氧组、低氧组及ADM、L-NAME、PD98059干预组，用MTT比色法和PCNA的免疫组化法测定细胞增殖反应，用流式细胞仪检测细胞凋亡，用Western blotting法检测HIF-1α、P-ERK1/2、iNOS的蛋白表达。结果: （1）低氧24 h组的A值明显高于常氧组(P<0.01)，而PD98059及ADM干预组明显低于低氧组(P<0.01)， L-NAME干预组明显高于低氧组和常氧组(P<0.01)。（2）免疫组化表明，低氧24 h组呈阳性表达(P<0.01)。PD98059、ADM抑制了PCNA的表达(P<0.01)， L-NAME促进了PCNA的表达(P<0.01)。（3）各组在低氧培养24 h后，凋亡指数差异无显著(均P＞0.05)。（4）Western blotting表明常氧组少量HIF-1α、iNOS、 P-ERK1/2表达，低氧4 h后均表达增高(P<0.01),8 h仍维持在高峰(P<0.01)，而HIF-1α、P-ERK1/2在低氧24 h后表达下调。L-NAME促进了HIF-1α表达(P<0.01),PD98059部分抑制了HIF-1α、iNOS及P-ERK1/2表达(P<0.01)；ADM部分抑制了HIF-1α表达，促进iNOS表达(P<0.01)。结论: 低氧能促进肺动脉平滑肌细胞增殖，对细胞的凋亡无影响；HIF-1在低氧诱导肺动脉平滑肌细胞增殖中起重要作用。     

香烟提取物对支气管哮喘大鼠气道平滑肌细胞增殖的影响

目的： 探讨香烟提取物（CSE）对支气管哮喘(简称哮喘)大鼠气道平滑肌细胞（ASMCs）增殖作用及可能机制。方法: 16只SD大鼠随机分为对照组和哮喘组,各8只。原代培养大鼠ASMCs,取第3-6代细胞,分为对照组、对照+CSE组、哮喘组、哮喘+CSE组、哮喘+CSE+嘧啶基-苯磺酰胺（GW8510,细胞周期蛋白依赖激酶-4抑制剂）组、哮喘+GW8510组。用流式细胞术、四甲基偶氮唑盐（MTT）法及增殖细胞核抗原（PCNA）免疫细胞化学技术检测ASMCs增殖;用逆转录-聚合酶链反应（RT-PCR）和蛋白质印迹（Western blotting）检测细胞周期蛋白D1(cyclin D1)的表达。结果: （1）哮喘组ASMCs与对照组ASMCs相比,在S+G2/M期比例、吸光度（A）值和PCNA表达率上明显增高,差异显著（P＜0.01）。（2）哮喘组ASMCs S+G2/M期比例、吸光度（A）值和PCNA表达率分别为(18.30±1.12)%、0.512±0.110、(55.1±3.7)%;哮喘+CSE组分别为（32.12±1.17）%、0.801±0.210、（90.2±7.3）%;哮喘+CSE+GW8510组分别为(17.21±0.95)%、0.508±0.009、(54.3±4.8)%;哮喘+GW8510组分别为(11.16±1.48)%、0.345±0.078、(40.6±5.4)%。除哮喘组、哮喘+CSE+GW8510组两组比较差异无显著外,其余两两比较差异均显著（P＜0.01）。（3）哮喘组、哮喘+CSE组、哮喘+CSE+GW8510组、哮喘+GW8510组ASMCs cyclin D1 mRNA A值比值和蛋白表达A值比值分别为0.236±0.045、0.271±0.002;0.369±0.124、0.379±0.002;0.231±0.075、0.261±0.002;0.165±0.064、0.193±0.002。除哮喘组、哮喘+CSE+GW8510组两组比较差异无显著外,其余两两比较差异均显著（P＜0.01）。结论: 正常与哮喘大鼠ASMCs在CSE干预后增殖明显加快,cyclin D1表达明显增加。CSE可能是通过cyclin D1参与调控哮喘大鼠ASMCs的增殖。     

川芎嗪对血管紧张素Ⅱ诱导的大鼠血管平滑肌细胞增殖中CaN活性及增殖细胞核抗原表达水平的影响

目的：观察川芎嗪对血管紧张素Ⅱ（AngⅡ）诱导的血管平滑肌细胞（VSMCs）中钙调神经磷酸酶（CaN）活性及增殖细胞核抗原（PCNA）表达水平的影响。方法：建立AngⅡ诱导VSMCs增殖模型，应用免疫细胞化学法观察血管平滑肌细胞PCNA表达；并用酶促反应定磷法测定CaN活性。结果：AngⅡ组能够明显刺激VSMCs增殖，VSMCs细胞数目和细胞增殖活度明显高于正常对照组（P＜0.01）；CaN活性和PCNA表达量（A值）显著高于正常对照组（P＜0.01）。同时加川芎嗪处理，各组CaN活性和PCNA表达水平均显著低于AngⅡ组（P＜0.01）。结论：川芎嗪对AngⅡ诱导的血管平滑肌细胞增殖有显著抑制作用，其机制与抑制CaN介导的信号转导进而抑制PCNA的表达有关。     

BQ123对大鼠肺动脉平滑肌细胞电压门控钾通道表达的影响

目的：探讨内皮素-1受体拮抗剂BQ123 对大鼠肺动脉平滑肌细胞电压门控钾通道亚型基因表达的影响。 方法： 根据常氧 (PO2 152 mmHg ) 及慢性低氧（PO2 40±5 mmHg）的不同培养条件，将肺动脉平滑肌细胞分为常氧组和慢性低氧组，并用BQ123分别处理上述两组细胞，采用半定量RT-PCR技术检测大鼠肺动脉平滑肌细胞Kv2.1、Kv9.3基因表达的变化。 结果： 经过慢性低氧，大鼠肺动脉平滑肌细胞Kv2.1、Kv9.3的mRNA表达水平明显低于常氧组（P<0.01，n=5），BQ123对常氧组Kv2.1的mRNA表达无影响（P>0.05，n=5），但可明显增加慢性低氧组Kv2.1的表达（P<0.01，n=5）。无论在常氧还是慢性低氧时，BQ123对Kv9.3的mRNA表达均无影响（P>0.05，n=5）。 结论： 慢性低氧可降低大鼠肺动脉平滑肌细胞电压门控钾通道的表达，内皮素-1受体拮抗剂BQ123可能通过抑制PASMCs的增殖，改变了细胞内信号转导通路中某些因子的表达，从而间接促进Kv的表达。     

慢性低氧性肺动脉高压大鼠肾上腺髓质素前体N端20肽的变化

目的：探讨慢性低氧性肺动脉高压和肺血管结构重建时肾上腺髓质素前体N端20肽（PAMP）的变化。方法:将18只雄性Wistar大鼠随机分为对照组和低氧组，每组各9只。常压低氧2周后，以右心导管法测定肺动脉平均压（mPAP），检测右心室与左心室加室间隔比值 ［RV/(LV+S)］，观测肺血管显微和超微结构的变化。并且以放免法测定血浆中PAMP含量，以免疫组化法检测肺组织中PAMP表达，以原位杂交检测肺组织中肾上腺髓质素（ADM） mRNA的表达。结果: 低氧组大鼠mPAP及RV/（LV+S）均明显高于对照组（均P<0.01）。光镜下，肺小血管肌化程度明显增强，肺中、小型肌型动脉相对中膜厚度明显增加。电镜下，肺腺泡内动脉内皮细胞增生、肿胀，内弹力层粗细不均，平滑肌细胞肥厚、向合成表型转化。并且低氧组大鼠血浆PAMP含量明显高于对照组（P<0.01），肺动脉PAMP表达和ADM mRNA表达均明显增强。结论：低氧后肺动脉PAMP表达和血浆PAMP含量的上调可能参与了慢性低氧性肺动脉高压和肺血管结构重建的形成。     

急性低氧大鼠肺动脉平滑肌内质网钙信号的变化及意义

目的：观察急性低氧大鼠肺动脉平滑肌内质网钙信号的变化及意义。方法:细胞水平：钙荧光探针(Fura-2/AM)负载大鼠肺动脉平滑肌细胞（PASMCs），荧光分光光度法，细胞外液无Ca2+及含Ca2+，在常氧（37 ℃、5% CO2、21 %O2、74 %N2 ）和急性低氧(37 ℃、5% CO2、2% O2、93 %N2)时，检测理阿诺碱（RD）和环匹阿尼酸（CPA）等对细胞浆内游离钙离子浓度（［Ca2+］i）的影响；离体血管环水平：相同条件，离体血管灌流方法检测肺动脉环张力变化。结果:(1)急性低氧时［Ca2+］i升高：常氧组［Ca2+］i为（96.99±7.16） nmol/L，低氧组为(257.06±32.48) nmol/L (P<0.01)。(2)与低氧组比较，预先用RD或普鲁卡因(procain)抑制内质网理阿诺碱受体敏感钙库，随后再给予低氧刺激时［Ca2+］i不升高，为（100.91±11.21） nmol/L (P<0.01)；而用CPA或thapsigargin（TG）抑制内质网摄取Ca2+，再给低氧刺激时［Ca2+］i呈升高状态(P>0.05)，而在细胞外液含钙及低氧下CPA及TG引起［Ca2+］i进一步升高(P<0.05)。(3)低氧引起肺动脉环收缩：常氧对基础张力无影响，低氧引起肺动脉环收缩，最大收缩张力达（49.28±8.64） g/g,P<0.01。(4)与低氧组比较，预先用RD或procain抑制内质网理阿诺碱受体敏感钙库，再给予低氧刺激，肺动脉环不收缩，最大收缩张力（3.75±1.14） g/g, P<0.01；而用CPA或TG后，再给予低氧刺激，肺动脉环呈收缩状态(P>0.05)，而在细胞外液含钙及低氧下CPA及TG引起肺动脉环进一步收缩(P<0.05)。结论:急性低氧可以引起内质网释放Ca2+，至少来自理阿诺碱受体敏感钙库的Ca2+释放参与了低氧肺血管收缩的发病机制；这可能是PASMCs自身具有的，既不依赖细胞外Ca2+内流，也不依赖血管内皮。     

环孢素A对神经肽Y刺激的大鼠血管平滑肌细胞增殖的影响

目的:观察环孢素A(CsA)对神经肽Y(NPY)诱导的大鼠主动脉平滑肌细胞增殖的影响,以探讨钙调神经磷酸酶(CaN)信号通路在血管平滑肌细胞增殖中的作用。方法:体外培养的大鼠主动脉平滑肌细胞分为3组:(1)NPY组,(2)CsA+NPY组,(3)对照组。检测CaN活性(定磷法)、细胞增殖活度(MTT法)的变化,观察增殖细胞核抗原(PCNA)的表达水平(免疫组化定量技术)。结果:NPY组CaN活性、血管平滑肌细胞增殖活度(吸光度表示),PCNA表达水平(光密度值表示)明显高于对照组(P＜0.01或P＜0.05),CsA+NPY组各项指标明显低于NPY组(P＜0.01或P＜0.05)。结论:环孢素A可显著阻滞神经肽Y刺激的血管平滑肌细胞增殖,这种作用可能通过抑制CaN信号通路所致。     

Kv1.5对大鼠低氧高二氧化碳性PASMCs增殖、凋亡的影响及与MAPK通路的关系

 目的：探讨电压依赖性钾离子通道Kv1.5对大鼠低氧高二氧化碳性肺动脉平滑肌细胞（PASMCs）增殖、凋亡的影响及其与丝裂原激活蛋白激酶（MAPK）信号通路的关系。方法：体外培养大鼠PASMCs,复制低氧高二氧化碳模型,随机分组如下：常氧组（N组）;低氧高二氧化碳组（HH组）;低氧高二氧化碳+溶剂DMSO对照组（HD组）;低氧高二氧化碳+ERK1/2通路抑制剂U0126组（HU组）;低氧高二氧化碳+p38 MAPK通路抑制剂SB203580组（HS组）;低氧高二氧化碳+MAPK通路激动剂茴香霉素（anisomycin）组（HA组）。采用CCK-8法检测细胞活性,蛋白免疫印迹法检测Kv1.5、增殖细胞核抗原（PCNA）及Bax蛋白的表达水平。结果：与N组相比,HH组和HD组细胞活性增加（P<0.01）,PCNA蛋白表达上调,Kv1.5及Bax蛋白表达均明显降低（P<0.01）,HH组和HD组间各指标变化均无显著差异（均P>0.05）;较之HD组,HU组、HS组及HA组细胞活性降低（P<0.05或P<0.01）,PCNA蛋白表达下调,Kv1.5及Bax蛋白表达均明显增加,差异均显著（P<0.01）,其中以HA组各指标变化最明显。结论：钾离子通道Kv1.5对低氧高二氧化碳性大鼠PASMCs增殖、凋亡的调节可能与MAPK通路的激活有关。     

肾上腺髓质素对血管紧张素II的促血管平滑肌细胞增殖作用的影响

观察肾上腺髓质素前体N端20肽（PAMP）和肾上腺髓质素（ADM ）对血管紧张素II（AngII）诱导的血管平滑肌细胞（VSMC）增殖的影响。用测定培养的大鼠VSMC3H-TdR掺入和蛋白激酶C（PKC）活性的方法。结果发现：10-8mol/L AngII刺激培养的VSMCs 3H-TdR掺入增加2.68倍（P＜0.01）、PKC活性增加1.02倍（P＜0.01）。而10-9mol/L-10-7mol/L的PAMP或ADM与10-8mol/L AngII同时孵育，则显著抑制AngII的上述作用（P＜0.01）。且两者的抑制作用无明显差异。PAMP和ADM均有抑制AngII所致的VSMC增殖作用，可能是通过抑制信号传导系统中的PKC活性来实现的。PAMP和ADM 与AngII相互作用，共同调节VSMC的增殖，从而维持循环系统功能的稳态。     

增殖细胞核抗原反义寡核苷酸对人脐血CD34+细胞分化的影响

目的:研究增殖细胞核抗原反义寡核苷酸（PCNA-ASODN）对脐血造血干/祖细胞体外扩增的调节作用。 方法:采用免疫磁珠分离技术从新鲜脐带血中分离CD34+细胞，使用不同浓度的PCNA-ASODN作用于体外扩增的CD34+细胞，应用流式细胞技术检测各种细胞数量，细胞内PCNA表达及细胞周期。 结果:加入了PCNA-ASODN的两个实验组，其PCNA的表达率为（27.2±3.6）%和(19.0±1.5)%，低于对照组的（53.8±8.3）%（P<0.01）。低浓度组扩增的细胞中CD34+细胞比例为（33.4±3.2）％，显著高于对照组的（25.2±2.6）%（P<0.01），而且CD34+CD38-细胞数量达到（57.8±9.9）倍，也显著高于对照组的（43.5±7.4）倍(P<0.01)。 结论:低浓度的PCNA-ASODN有效抑制CD34+细胞在增殖过程中PCNA表达，减缓扩增过程中的分化作用，提高了早期祖细胞的扩增效率。     

Cytokeratins in smooth muscle cells and smooth muscle tumours

A keratin positive metastatic leiomyosarcoma in the lung, which resulted in diagnostic error, is reported. The results of additional studies of 17 benign and malignant leiomyogenic tumours with various keratin antibodies are presented and discussed in the light of recent bibliographical data.     

Cytokeratin expression in smooth muscle and smooth muscle tumours

The expression of cytokeratin intermediate filaments by a tumour has been accepted as evidence of an epithelial origin. Although there have been anecdotal reports of cytokeratin expression within tissues and neoplasms of non-epithelial origin, particularly muscle, there have been no comprehensive studies of its frequency and distribution. In order to investigate this we have studied 51 cases of normal smooth muscle and benign and malignant smooth muscle tumours using a panel of monoclonal antibodies against a range of intermediate filaments (cytokeratins, desmin and vimentin). Cytokeratin expression was noted overall in 50% of normal, benign and malignant smooth muscle tissues. Such expression tended to have a focal or patchy distribution. No case expressed cytokeratins in the absence of both desmin and vimentin. The implication of these findings for diagnostic immunocytochemistry is that intermediate filaments alone are not completely reliable markers of tumour histogenesis and should be used as part of a larger panel of monoclonal antibodies.     

pH and smooth muscle

In this paper, the control of vascular smooth muscle intracellular pH (pH_i) and the mechanisms of importance for the vasodilation to acidosis are reviewed. The three transport pathways of importance for the control of pH_i are a sodium-coupled bicarbonate transport, a Na,H-exchanger and a Cl,HCO₃^?exchange. While the two latter pathways are present in all smooth muscle cells studied, the sodium-coupled bicarbonate transport may be present in two forms which are either coupled to chloride efflux or are independent of chloride. The chloride-independent pathway seems electroneutral, indicating a 1:1 stoichiometry. All three transporters can be activated by vasoactive hormones and the second messengers involved are under intense investigation. With respect to the mechanisms involved in the vasodilation to acidosis, there seems to be a nitric oxide-dependent pathway as well as a direct effect of acidosis on the smooth muscle cells. In some preparations, prostanoids may also be involved. The direct vasodilator effect of acidosis is probably mediated through reduction of extracellular pH and the acidosis is associated with a reduction of the intracellular calcium concentration, which could explain the reduction of smooth muscle tone.     

Renal smooth muscle hamartoma

A large (4 cm in diameter) smooth muscle tumor was found in the medial aspect of the right kidney in a 54-year-old Caucasian woman with acute hypertension. Clonality assay (HUMARA) showed no evidence of clonal proliferation, and array comparative genomic hybridization (aCGH) analysis failed to identify any copy number genomic change. These findings are consistent with smooth muscle hamartoma, a rare benign renal tumor-like lesion.     

Aging and gastrointestinal smooth muscle

The present review is an attempt to put into perspective the available information on the putative changes in cellular mechanisms of the contractile properties of the aging gastrointestinal (GI) smooth muscle. Information on smooth muscle of the GI tract is scanty. Smooth muscle cells from old rats (32 months old) exhibit limited cell length distribution and diminished contractility. The observed reduced contractile response may be due to the effect of aging on signal transduction pathways, especially an inhibition of the tyrosine kinase-Src kinase pathway, a reduced activation of the PKCalpha pathway, a reduced association of contractile proteins (HSP27-tropomyosin, HSP27-actin, and actin-myosin). Levels of HSP27-phosphorylation are also reduced compared to adult rats. Regulation of GI motility is a complex mechanism of signal transduction and interaction of signaling and contractile proteins. It is suggested that further studies to elucidate the role of HSP27 in aging smooth muscle of the GI tract are needed.     

Hypertrophy of visceral smooth muscle

Summary Smooth muscles of viscera undergo a large increase in volume when there is a chronic, partial obstruction impairing the flow of lumenal contents. Hypertrophy of smooth muscle occurs in various medical conditions and several methods are available for inducing it experimentally in laboratory animals, especially in urinary bladder, small intestine and ureter. The hypertrophic response differs somewhat with the type of organ, the animal species, the age of the subject, and the experimental procedure.Ten- to fifteen-fold increases in muscle volume develop within a few weeks in the urinary bladder or the ileum of adult animals, a growth that would not have occurred in the lifespan of the animal without the experimental intervention. The general architecture of the muscle and the boundaries with adjacent tissues are well preserved. In intestinal hypertrophy, muscle cells increase in number: mitoses are found in mature, fully differentiated muscle cells. Cell division by full longitudinal splitting of muscle cells may also occur.Enlargement of muscle cells accounts for most of the muscle hypertrophy. The hypertrophic muscle cell has an irregular profile with deep indentations of the cell membrane, bearing caveolae and dense bands; however, the cell surface grows less than the cell volume (reduction of surface-to-volume ratio). The nucleus is crenated and is much less enlarged than the cell (reduction of the nucleo-plasmatic ratio). Mitochondria grow in number but in some muscles their spatial density decreases; intermediate filaments increase more than myofilaments. The spatial density of sarcoplasmic reticulum is generally increased. In the hypertrophic intestine, gap junctions increase in number and size; in the bladder, gap junctions are absent both in control and in hypertrophy. Thus the hypertrophic muscle cell is not only larger than a control cell, but has a different pattern of its structural components.Extensive neo-angiogenesis maintains a good blood supply to the hypertrophic muscle. The density of innervation is much decreased in the hypertrophic intestine, whereas it appears well maintained in the bladder. Neuronal enlargement is found in the intramural ganglia of the intestine and in the pelvic ganglion.The mechanisms involved in hypertrophic growth are unknown. Three possible factors, mechanical factors, especially stretch, altered nerve discharge, and trophic factors are discussed.     

Cable properties of smooth muscle

1. The cable properties of smooth muscle of guinea-pig taenia coli were studied by intracellular recording of electrotonic potentials produced by square current pulses and alternating current applied with external electrodes.2. An electrical model of the smooth muscle was constructed to test how the junctional resistance between cells affected the cable properties. The model consisted of a series of short cables (representing cells) which were connected by junctional resistances.3. It was concluded, from the experiments on the living tissue and on the model, that the electrotonic potential in smooth muscle can be expressed by the ordinary cable equation used for nerve and skeletal muscle fibres, even though the junctional resistance is of the same order of magnitude as that of the myoplasmic resistance.4. The cable equation was used to analyse the membrane parameters from the electrotonic potential, from the time course of the foot of the spike and from the conduction velocity. The analysis indicates that the smooth muscle has a membrane capacity of 2-3 muF/cm(2) and a membrane resistance of 30-50 kOmega cm(2).