HIF-1α promotes the proliferation and migration of pulmonary arterial smooth muscle cells via activation of Cx43

The proliferation of pulmonary artery smooth muscle cells (PASMCs) is an important cause of pulmonary vascular remodelling in hypoxia-induced pulmonary hypertension (HPH). However, its underlying mechanism has not been well elucidated. Connexin 43 (Cx43) plays crucial roles in vascular smooth muscle cell proliferation in various cardiovascular diseases. Here, the male Sprague-Dawley (SD) rats were exposed to hypoxia (10% O₂) for 21 days to induce rat HPH model. PASMCs were treated with CoCl₂ (200 µM) for 24 h to establish the HPH cell model. It was found that hypoxia up-regulated the expression of Cx43 and phosphorylation of Cx43 at Ser 368 in rat pulmonary arteries and PASMCs, and stimulated the proliferation and migration of PASMCs. HIF-1α inhibitor echinomycin attenuated the CoCl₂-induced Cx43 expression and phosphorylation of Cx43 at Ser 368 in PASMCs. The interaction between HIF-1α and Cx43 promotor was also identified using chromatin immunoprecipitation assay. Moreover, Cx43 specific blocker (^37,43Gap27) or knockdown of Cx43 efficiently alleviated the proliferation and migration of PASMCs under chemically induced hypoxia. Therefore, the results above suggest that HIF-1α, as an upstream regulator, promotes the expression of Cx43, and the HIF-1α/Cx43 axis regulates the proliferation and migration of PASMCs in HPH.     

The hypoxia-induced microRNA-130a controls pulmonary smooth muscle cell proliferation by directly targeting CDKN1A

Excessive proliferation of human pulmonary artery smooth muscle cells (HPASMC) is one of the major factors that trigger vascular remodeling in hypoxia-induced pulmonary hypertension. Several studies have implicated that hypoxia inhibits the tumor suppressor p21 (CDKN1A). However, the precise mechanism is unknown.The mouse model of hypoxia-induced PH and in vitro experiments were used to assess the impact of microRNAs (miRNAs) on the expression of CDKN1A. In these experiments, the miRNA family miR-130 was identified to regulate the expression of CDKN1A. Transfection of HPASMC with miR-130 decreased the expression of CDKN1A and, in turn, significantly increased smooth muscle proliferation. Conversely, inhibition of miR-130 by anti-miRs and seed blockers increased the expression of CDKN1A. Reporter gene analysis proved a direct miR-130–CDKN1A target interaction. Exposure of HPASMC to hypoxia was found to induce the expression of miR-130 with concomitant decrease of CDKN1A. These findings were confirmed in the mouse model of hypoxia-induced pulmonary hypertension showing that the use of seed blockers against miR-130 restored the expression of CDKN1A.These data suggest that miRNA family miR-130 plays an important role in the repression of CDKN1A by hypoxia. miR-130 enhances hypoxia-induced smooth muscle proliferation and might be involved in the development of right ventricular hypertrophy and vascular remodeling in pulmonary hypertension.     

Suppression of Akt1 phosphorylation by adenoviral transfer of the PTEN gene inhibits hypoxia-induced proliferation of rat pulmonary arterial smooth muscle cells

Recent findings identify the role of proliferation of pulmonary artery smooth muscle cells (PASMCs) in pulmonary vascular remodeling. Phosphoinositide 3 kinase (PI3K) and serine/threonine kinase (Akt) proteins are expressed in vascular smooth muscle cells. In addition, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) has been identified as a negative regulator of cytokine signaling that inhibits the PI3K-Akt pathway. However, little is known about the role of PTEN/Akt signaling in hypoxia-associated vascular remodeling. In this study, we found that hypoxia-induced the expression of Akt1 mRNA and phosphorylated protein by at least twofold in rat PASMCs. Phospho-PTEN significantly decreased in the nuclei of PASMCs after hypoxic stimulation. After forcing over-expression of PTEN by adenovirus-mediated PTEN (Ad-PTEN) transfection, the expression of phospho-Akt1 was significantly suppressed in PASMCs at all time-points measured. Additionally, we showed here that hypoxia increased proliferation of PASMCs by nearly twofold and over-expression of PTEN significantly inhibited hypoxia-induced PASMCs proliferation. These findings suggest that phospho-PTEN loss in the nuclei of PASMCs under hypoxic conditions may be the major cause of aberrant activation of Akt1 and may, therefore, play an important role in hypoxia-associated pulmonary arterial remodeling. Finally, the fact that transfection with Ad-PTEN inhibits the phosphorylation of Akt1 in PASMCs suggests a potential therapeutic effect on hypoxia-associated pulmonary arterial remodeling.     

miR-21 regulates chronic hypoxia-induced pulmonary vascular remodeling

Chronic hypoxia causes pulmonary vascular remodeling leading to pulmonary hypertension (PH) and right ventricle (RV) hypertrophy. Aberrant expression of microRNA (miRNA) is closely associated with a number of pathophysiologic processes. However, the role of miRNAs in chronic hypoxia-induced pulmonary vascular remodeling and PH has not been well characterized. In this study, we found increased expression of miR-21 in distal small arteries in the lungs of hypoxia-exposed mice. Putative miR-21 targets, including bone morphogenetic protein receptor (BMPR2), WWP1, SATB1, and YOD1, were downregulated in the lungs of hypoxia-exposed mice and in human pulmonary artery smooth muscle cells (PASMCs) overexpressing miR-21. We found that sequestration of miR-21, either before or after hypoxia exposure, diminished chronic hypoxia-induced PH and attenuated hypoxia-induced pulmonary vascular remodeling, likely through relieving the suppressed expression of miR-21 targets in the lungs of hypoxia-exposed mice. Overexpression of miR-21 enhanced, whereas downregulation of miR-21 diminished, the proliferation of human PASMCs in vitro and the expression of cell proliferation associated proteins, such as proliferating cell nuclear antigen, cyclin D1, and Bcl-xL. Our data suggest that miR-21 plays an important role in the pathogenesis of chronic hypoxia-induced pulmonary vascular remodeling and also suggest that miR-21 is a potential target for novel therapeutics to treat chronic hypoxia associated pulmonary diseases.     

MicroRNA-30c contributes to the development of hypoxia pulmonary hypertension by inhibiting platelet-derived growth factor receptor β expression

Pulmonary arterial hypertension (PAH) is characterized by excessive proliferation and resistance to apoptosis of pulmonary artery smooth muscle cells (PASMCs). MicroRNAs have been implicated in the regulation of cell proliferation and might be implicated in the etiology of PAH. Data from in vivo and in vitro cell culture models showed that hypoxia inhibits microRNA-30c (miR-30c) expression in PASMCs. Inhibition of miR-30c by either hypoxia or AMO-30c results in PASMC proliferation (cell viability, 5-bromo-2-deoxyuridine (BrdU) incorporation, proliferating cell nuclear antigen, Ki67, and tubulin polymerization) and the inhibition of apoptosis (cell cycle progression, Cyclin A and Cyclin D, and TUNEL staining). Moreover, down-regulation of miR-30c also results in the phenotype switch from contractile to synthetic PASMC (SM22α and Calponin, osteopontin expression, and wound healing assay). In contrast, these effects were reversed by the application of an miR-30c mimetic under hypoxic conditions. Mechanically, miR-30c inhibited the platelet-derived growth factor receptor β (PDGFRβ) expression by directly binding to the 3′ untranslated region of PDGFRβ mRNA (luciferase reporter assays, and PDGFRβ-masking antisense oligodeoxynucleotides). Pharmacological inhibition of PDGFR by AG-1296 displayed similar effects to the miR-30c mimetic. These data suggest that the down-regulation of miR-30c accounts for the up-regulation of PDGFRβ expression, and subsequent activation of PDGF signaling results in the hypoxia-induced PASMC proliferation and phenotype switching. Therefore, increasing miR-30c expression levels could be explored as a potential new therapy for hypoxia-induced PAH.     

MicroRNA-18a通过HIF-1-alpha调控缺氧引起的人肺动脉平滑肌细胞增殖

目的：研究microRNA-18a (miR-18a) 对缺氧引起的人肺动脉平滑肌细胞(human pulmonary artery smooth muscle cells, hPASMCs)增殖的调控作用及其可能机制。方法：体外培养hPASMCs,分为未转染组、miR-18a 模拟物对照组、miR-18a 模拟物组、 miR-18a 抑制剂对照组、miR-18a 抑制剂组、siRNAcontrol组、siHIF-1-alpha组、miR-18a 抑制剂和siHIF-1-alpha共转染组。分别于常氧(21% O2)和低氧(3%O2)作用24小时。采用CCK-8 法检测细胞的增殖情况,萤光素酶报告基因系统验证缺氧诱导因子-1-alpha(HIF-1alpha)是 否为miR-18a 的靶基因,并通过western-blot 以及实时荧光定量PCR 技术检测相关蛋白和基因的表达。结果：缺氧可促进 hPASMCs 增殖,使miR-18a 表达减少;miR-18a 模拟物可抑制hPASMCs 增殖,而miR-18a 抑制剂可促进hPASMCs 增殖;抑制 miR-18a 可使HIF-1-alpha的表达上调。同时抑制miR-18a 和HIF-1-alpha,可使miR-18a 对hPASMCs 增殖调控的能力消失。结论：缺氧通 过抑制miR-18a,上调HIF-1-alpha的表达,促进hPASMCs增殖。     

ET－1，NO和缺氧对肺动脉平滑肌细胞钙内流及胶原合成的影响

肺血管平滑肌细胞是肺血管收缩反应的主要执行者,也是肺血管结构重建的重要参与者。本研究观察了内皮素１（ＥＴ１）,一氧化氮（ＮＯ）和缺氧对培养的新生小牛肺动肺平滑肌细胞（ＰＡＳＭＣ）钙内流以及胶原合成的影响。结果表明ＥＴ１和缺氧可促进ＰＡＳＭＣ的钙内流,ＮＯ供应剂硝普钠（ＳＭＰ）可抑制ＥＴＩ诱导的钙内流,其作用呈剂量依赖性,ＳＮＰ还可以剂量依赖地抑制ＰＡＳＭＣ的胶原合成,而缺氧可促进ＰＡＳＭＣ的胶原合成。     

MMP-10 from M1 macrophages promotes pulmonary vascular remodeling and pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is characterized by muscularized pulmonary blood vessels, leading to right heart hypertrophy and cardiac failure. However, state-of-the-art therapeutics fail to target the ongoing remodeling process. Here, this study shows that matrix metalloproteinases (MMP)-1 and MMP-10 levels are increased in the medial layer of vessel wall, serum, and M1-polarized macrophages from patients with PAH and the lungs of monocrotaline- and hypoxia-induced PAH rodent models. MMP-10 regulates the malignant phenotype of pulmonary artery smooth muscle cells (PASMCs). The overexpression of active MMP-10 promotes PASMC proliferation and migration via upregulation of cyclin D1 and proliferating cell nuclear antigen, suggesting that MMP-10 produced by infiltrating macrophages contributes to vascular remodeling. Furthermore, inhibition of STAT1 inhibits hypoxia-induced MMP-10 but not MMP-1 expression in M1-polarized macrophages from patients with PAH. In conclusion, circulating MMP-10 could be used as a potential targeted therapy for PAH.     

AQP1促进肺动脉平滑肌细胞的增殖与迁移（应作者要求撤稿）

该文应作者要求已撤稿。肺动脉平滑肌细胞（PASMCs）的迁移和增殖是肺动脉重塑进而造成肺动脉高压的主要病理基础。水通道蛋白1（AQP1）具有促进上皮细胞、内皮细胞迁移的作用,但机制不清。由于AQP1也表达于血管平滑肌细胞,推测AQP1可能参与缺氧诱导的PASMCs增殖及迁移。通过PCR和免疫印迹分析,检测AQP的表达以及缺氧对AQP表达水平的影响,并通过细胞迁移以及增殖实验观察AQP1在缺氧诱导的PASMCs迁移与增殖中的作用。AQP1在PASMCs和主动脉平滑肌细胞（AoSMCs）均表达,但缺氧只增加PASMCs中AQP1的表达,以及促进PASMCs的迁移与增殖。敲除AQP1可抑制PASMCs的增殖以及缺氧诱导的细胞增殖和迁移。过表达AQP1促进PASMCs的增殖和迁移。缺氧促进β联蛋白在PASMCs内的表达。敲除β联蛋白后,抑制AdAQP1所介导的PASMCs迁移与增殖。这些结果表明,缺氧可促进AQP1在肺动脉内的表达,AQP1可通过β联蛋白对PASMCs的增殖和迁移进行调节。     

PVT1促进PAH大鼠肺动脉平滑肌细胞增殖和迁移的作用机制研究

摘要 目的：研究浆细胞瘤多样异位基因1（PVT1）在肺动脉高压（PAH）大鼠中对于肺动脉平滑肌细胞(PASMCs)增殖和迁移的作用及其可能的机制。方法：将16只成年雄性SD大鼠随机分为肺动脉高压组（PAH组）和对照组,每组8只大鼠。PAH组大鼠通过单次项背部皮下注射MCT溶液造模,对照组大鼠给予单次项背部皮下注射等量生理盐水。通过胸右心室穿刺法测量右心室压力。取各组大鼠肺组织,并进行原代肺动脉平滑肌细胞分离培养。通过RT-qPCR和Western blot检测PVT1及Fxr1在PAH组织及PASMCs中的表达水平;通过HE染色评估PAH组织的血管壁形态;免疫荧光法检测HPASMC的纯度;CCK-8法和伤口愈合迁移实验检测PASMCs增殖和迁移情况。结果：与对照组相比,PAH组大鼠肺组织血管壁厚度偏厚、肺动脉压显著升高（P<0.05）。PVT1在PAH组大鼠的PAH组织和PASMCs中的表达水平显著上调（P<0.05）,且其表达与肺动脉压呈正相关。与对照组相比,转染sh-PVT1的PASMCs显示出较低的细胞活力,同时转染sh-PVT1有效敲低了PASMCs中PVT1的表达水平（P<0.01）。与对照组相比,PVT1的敲低抑制了PASMCs迁移能力（P<0.01）。在转染pcDNA-PVT1的PASMCs中发现较高的增殖能力,PVT1的过表达促进了PASMCs迁移能力（P<0.01）。与对照组相比,Fxr1在PAH模型组的PAH组织和PASMCs中的表达水平显著上调（P<0.01）。结论：PVT1通过调节Fxr1的表达促进PASMCs的增殖和迁移,PVT1可能是PAH诊断和预测指标。     

Over-expression of PKGIα inhibits hypoxia-induced proliferation, Akt activation, and phenotype modulation of human PASMCs: the role of phenotype modulation of PASMCs in pulmonary vascular remodeling

The proliferation of pulmonary artery smooth muscle cells (PASMCs) plays a role in pulmonary vascular remodeling (PVR). Recently, it was shown that vascular smooth muscular cell phenotype modulation is important for their proliferation in other diseases. However, little is known about the role of human PASMC phenotype modulation in the proliferation induced by hypoxia and its molecular mechanism during PVR. In this study, we found using primary cultured human PASMCs that hypoxia suppressed the expression of endogenous PKGIα, which was reversed by transfection with a recombinant adenovirus containing the full-length cDNA of PKGIα (Ad-PKGIα). Ad-PKGIα transfection significantly attenuated the hypoxia-induced downregulation of the expression of smooth muscle α-actin (SM-α-actin), myosin heavy chain (MHC) and calponin in PASMCs, indicating that hypoxia-induced phenotype modulation was blocked. Furthermore, flow cytometry and ³H-TdR incorporation demonstrated that hypoxia-induced PASMC proliferation was suppressed by upregulation of PKGIα. These results suggest that enhanced PKGIα expression inhibited hypoxia-induced PASMC phenotype modulation and that it could reverse the proliferation of PASMCs significantly. Moreover, our previous work has demonstrated that Akt protein is activated in the process of hypoxia-induced proliferation of human PASMCs. Interestingly, we found that Akt was not activated by hypoxia when PASMC phenotype modulation was blocked by Ad-PKGIα. This result suggests that blocking phenotype modulation might be a key up-stream regulatory target.     

MiR-20a regulates the PRKG1 gene by targeting its coding region in pulmonary arterial smooth muscle cells

Chronic hypoxia triggers pulmonary vascular remodeling, which is associated with de-differentiation of pulmonary artery smooth muscle cells (PASMC). Here, we show that miR-20a expression is up-regulated in response to hypoxia in both mouse and human PASMC. We also observed that miR-20a represses the protein kinase, cGMP-dependent, type I (PRKG1) gene and we identified two crucial miR-20a binding sites within the coding region of PRKG1. Functional studies showed that miR-20a promotes the proliferation and migration of human PASMC, whereas it inhibits their differentiation. In summary, we provided a possible mechanism by which hypoxia results in decreased PRKG1 expression and in the phenotypic switching of PASMC.     

LncRNA LEF1-AS1 regulates the migration and proliferation of vascular smooth muscle cells by targeting miR-544a/PTEN axis

Long noncoding RNAs (lncRNAs) play important roles in endothelium development. A lncRNA, LEF1-AS1, is recently emerging as a potent mediator of the proliferation and migration of a number of cells, including smooth muscle cells. However, the effects of LEF1-AS1 in atherosclerosis remains largely unknown. Specimens from patients with coronary artery atherosclerosis were collected. The quantitative real-time polymerase chain reaction was used to analyze levels of LEF1-AS1 and microRNA-544a (miR-544a). Western blot analysis was used to assess PTEN, P-Akt, and T-Akt protein expression. Proliferation, migration, and invasion of cells were analyzed by cell counting kit-8 assay, scratch wound assay, and transwell assay, respectively. The interaction between LEF1-AS1, miR-544a, and PTEN was probed using bioinformatical analysis and dual-luciferase assay. In plasma and tissue of patients with coronary artery atherosclerosis, LEF1-AS1 was upregulated and miR-544a was downregulated. A negative correlation was found between LEF1-AS1 and miR-544a. miR-544a overexpression reversed the inhibition of LEF1-AS1 in smooth muscle cell proliferation and invasion, which were mediated through the PTEN pathway. LEF1-AS1 regulates smooth muscle cell proliferation and migration through the miR-544a/PTEN axis, indicating that LEF1-AS1 may be a potential therapeutic target in atherosclerosis.     

Gene expression of cyclin-dependent kinase inhibitors and effect of heparin on their expression in mice with hypoxia-induced pulmonary hypertension

The balance between cell proliferation and cell quiescence is regulated delicately by a variety of mediators, in which cyclin-dependent kinases (CDK) and CDK inhibitors (CDKI) play a very important role. Heparin which inhibits pulmonary artery smooth muscle cell (PASMC) proliferation increases the levels of two CDKIs, p21 and p27, although only p27 is important in inhibition of PASMC growth in vitro and in vivo. In the present study we investigated the expression profile of all the cell cycle regulating genes, including all seven CDKIs (p21, p27, p57, p15, p16, p18, and p19), in the lungs of mice with hypoxia-induced pulmonary hypertension. A cell cycle pathway specific gene microarray was used to profile the 96 genes involved in cell cycle regulation. We also observed the effect of heparin on gene expression. We found that (a) hypoxic exposure for two weeks significantly inhibited p27 expression and stimulated p18 activity, showing a 98% decrease in p27 and 81% increase in p18; (b) other CDKIs, p21, p57, p15, p16, and p19 were not affected significantly in response to hypoxia; (c) heparin treatment restored p27 expression, but did not influence p18; (d) ERK1/2 and p38 were mediators in heparin upregulation of p27. This study provides an expression profile of cell cycle regulating genes under hypoxia in mice with hypoxia-induced pulmonary hypertension and strengthens the previous finding that p27 is the only CDKI involved in heparin regulation of PASMC proliferation and hypoxia-induced pulmonary hypertension.     

低氧对培养的不同内径的肺动脉平滑肌细胞增殖的影响

目的和方法：分离培养三种不同内径的肺动脉平滑肌细胞（PASMCs）,用^3H－TdR掺入速率和细胞计数作为细胞增殖的指标,观察低氧对其增殖作用的影响。结果：低氧对三种不同内径的PASMCs（内径分别为＞1000μm、500－800μm、300-400μm）增殖促进作用显著不同,其^3H－TdR掺入速率和细胞计数分别增加23.5％和11.1％、60.0％和33.8％、141.4％和52.0％,选择对低氧最敏感的PASMCs（内径为300－400μm）,进一步探讨低氧促PASMCs增殖作用的细胞机制：钙拮抗剂verapail、蛋白激酶C抑制剂staurosporine(Stau)和细胞Na-H交换抑制剂amiloride可显著降低低氧情况下PASMCs^3H－TdR掺入速率和细胞计数。结论：低氧对三种不同内径的PASMCs增殖促进作用显著不同; Ca^2 、蛋白激酶C和Na^2 －H^ 交换的激活,可能是低氧促PASMCs增殖的重要胞内信息转导机制。     

15-oxo-Eicosatetraenoic acid prevents serum deprivation-induced apoptosis of pulmonary arterial smooth muscle cells by activating pro-survival pathway

Pulmonary arterial hypertension (PAH) is a progressive condition in which remodeling of the pulmonary vasculature plays an important role. The vascular remodeling involves pulmonary arterial smooth muscle cell (PASMC) proliferation and apoptosis, which is affected by several arachidonic acid metabolites. 15-oxo-Eicosatetraenoic acid (15-oxo-ETE) is one of the metabolites. However, the biological role of 15-oxo-ETE in PASMCs remains unknown. Here we show evidence for the modulation of PASMC apoptosis by 15-oxo-ETE. We found that 15-oxo-ETE increased rat and human PASMC viability. Consistently, 15-oxo-ETE attenuated nuclear fragmentation and DNA strand breaks, decreased caspase-3 activity, reduced mitochondrial depolarization, and increased Bcl-2 expression. Interestingly, the anti-apoptotic effect of 15-oxo-ETE was lost when the Akt intracellular signaling pathway was blocked. Taken together, we have established that 15-oxo-ETE protects PASMCs against apoptosis through the Akt pathway. These results suggest that 15-oxo-ETE seems to be a potential agent for PAH controls by preventing unwanted PASMC death.     

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.     

慢性低氧所致肺动脉高压对大鼠肺血管平滑肌细胞及成纤维细胞中蛋白激酶CβI的膜转位和蛋白表达量的影响

目的通过观察慢性低氧所致肺动脉高压对大鼠肺血管平滑肌细胞及成纤维细胞中蛋白激酶CBI（PKCβI）的膜转位和蛋白表达量的影响,初步探讨PKCpI在慢性低氧诱导大鼠肺动脉高压的发生、发展过程中所起的作用。方法建立慢性常压低氧肺动脉高压大鼠模型,将雄性SD大鼠随机分为正常对照组、低氧1d、3d、7d、14d和21d组,应用蛋白免疫印迹和免疫组化技术检测肺动脉高压形成过程中大鼠肺血管平滑肌细胞及成纤维细胞中PKCβI的膜转位和蛋白表达水平。结果（1）RVSP和RV／（LV＋S）比值较正常对照组明显增加（P〈0．05）,低氧后3d、7d、14d和21d后大鼠肺血管明显增厚;（2）大鼠肺血管平滑肌细胞和成纤维细胞均有PKCβI的表达,且低氧14d后PKCβI的蛋白表达量较正常对照组相比降低（P〈0．05）。结论PKCβI蛋白表达量的下调可能参与了慢性低氧诱导的大鼠肺动脉高压肺血管重塑的发生、发展过程。