Influence of atherosclerosis on vascular responsiveness in isolated rabbit vascular smooth muscle

Summary Coronary arteries and aortic rings were isolated from rabbits fed either a control diet or a high cholesterol (1 to 2%) diet for 8 to 11 weeks and studied for their vasoactive properties to a variety of vasoconstrictor and vasodilator agents. Perfused coronary arteries without intact endothelium constrict markedly to a thromboxane A₂ agonist (i.e., carbocyclic thromboxane A₂, CTA₂) and dilate markedly to iloprost, a prostacyclin analog. No differences occurred between the coronary arteries isolated from control or atherosclerotic rabbits. Additional studies were conducted on rabbit aortic vascular smooth muscle rings containing functionally intact endothelium and in rings denuded of their endothelium. Acetylcholine (20 to 2000 ng/ml) neither constricted nor dilated control aortic rings without endothelium, and markedly dilated aortic rings with intact endothelium in a concentration dependent manner. In atherosclerotic aortic rings, acetylcholine constricted preparations without endothelium, and dilated rings with endothelium to a much lesser extent than that observed in control rings. Similar reductions in responsiveness occurred with adenosine diphosphate (ADP), another endothelium-dependent vasodilator, but not with iloprost, a nonendothelium-dependent dilator. No differences were observed in constrictor responses to norepinephrine. Aortae from atherosclerotic rabbits produced less prostacyclin in response to arachidonic acid than control aortae. These data point to an important role of the endothelium in modulating the vascular response to vasodilators in atherosclerotic rabbit arterial vessels.This study was supported in part by Research Grant No. HL-25575 from the National Heart Lung and Blood Institute of the NIH.John A. Osborne is a Predoctoral Fellow of the Foerderer Foundation. Jian-zhong Sun is a WHO Postdoctoral Fellow.     

Vasoactive effects of eicosapentaenoic acid on isolated vascular smooth muscle

Summary Dietary intake of unsaturated fatty, acid of eicosapentaenoic acid (EPA) is thought to reduce the size and incidence of myocardial infarction. These beneficial effects are postulated to be due to chronic antithrombotic properties of EPA itself. We studied the possible direct effects of EPA on vascular smooth muscle as well as the ability of EPA to modify the vasoactivity of constrictor mediators in rabbit and cat aortic rings and isolated cat coronary arterics. EPA concentration-dependently (30 to 300 M) relaxed rabbit and cat aortic rings having an intact endothelium, while EPA did not show any significant vasodilator effects on rings without an endothelium. This EPA-induced vasorelaxation was not altered by the cyclooxygenase inhibitor ibuprofen, but was totally abolished by the guanylate cyclase inhibitor methylene blue, indicating an endothelium-dependent smooth muscle relaxation mechanism. In isolated perfused cat coronary arteries, EPA (3 to 300 M) exerted a dilator effect which was endothelium-independent and not affected by ibuprofen. The response was attenuated by propyl gallate, a lipoxygenase inhibitor. EPA also inhibited leukotriene (LT) C₄, (50 nM) and LTD₄ (50 nM)-induced vasoconstriction of isolated cat coronary arteries ranging from a blockade of 10% to 15% (P<0.05) at 3 M of EPA to a blockade of 89% to 93% (P<0.01) at 300 M. In contrast, the thromboxane analog, CTA₂, induced coronary constriction was not significantly altered by EPA. Thus, EPA produces endothelium-dependent relaxation in rabbit and cat aorta and endothelium-independent vasodilation in cat coronary arteries (i.e., intact vessels or helical strips). Moreover, EPA exerts acute anti-leukotriene actions in coronary arteries. In the case of long-term dietary intake of EPA, these actions may contribute to the protective action of EPA in myocardial ischemia.Supported in part by NIH Grant No. HL-25575 from the National Heart Lung and Blood Institute of the NIH.     

亲脂素增加血管平滑肌细胞的脂质集聚

目的 观察乙酰化的低密度脂蛋白(AcLDL)对血管平滑肌细胞亲脂素(adipophilin)表达的影响及亲脂素对血管平滑肌细胞的AcLDL摄取及脂质集聚的影响.从而探讨其在糖尿病大血管病变发生中的作用.方法 以不同浓度AcLDL干预人血管平滑肌细胞(HVSMCs).应用Northern印迹及Western印迹技术检测AcLDL对亲脂素表达的影响;以RNA干扰技术、流式细胞仪、酶法和油红O染色检测亲脂素对HVSMCs的脂质集聚及AcLDL摄取的影响.结果 AcLDL呈剂量依赖性地增加HVSMCs的亲脂素的表达,沉默亲脂素基因使HVSMCs对AcLDL的摄取(降低38.7%,P<0.05)和脂质集聚能力下降(甘油三酯、总胆固醇分别下降30.6%和29.8%,均P<0.01).结论 亲脂素促进HVSMCs摄取AcLDL,增加HVSMCs脂质集聚,这可能是亲脂素促进动脉粥样硬化的机制之一.     

Sodium current in human jejunal circular smooth muscle cells.

BACKGROUND & AIMS: Sodium channels are key regulators of neuronal and muscle excitability. However, sodium channels have not been definitively identified in gastrointestinal smooth muscle. The aim of the present study was to determine if a Na(+) current is present in human jejunal circular smooth muscle cells. METHODS: Currents were recorded from freshly dissociated cells using patch-clamp techniques. Complementary DNA (cDNA) libraries constructed from the dissociated cells were screened to determine if a message for alpha subunits of Na(+) channels was expressed. Smooth muscle cells were also collected using laser-capture microdissection and screened. RESULTS: A tetrodotoxin-insensitive Na(+) channel was present in 80% of cells patch-clamped. Initial activation was at -65 mV with peak inward current at -30 mV. Steady-state inactivation and activation curves revealed a window current between -75 and -60 mV. The Na(+) current was blocked by lidocaine and internal and external QX314. A cDNA highly homologous to SCN5A, the alpha subunit of the cardiac Na(+) channel, was present in the cDNA libraries constructed from dissociated cells and from smooth muscle cells collected using laser-capture microdissection. CONCLUSIONS: Human jejunal circular smooth muscle cells express a tetrodotoxin-insensitive Na(+) channel, probably SCN5A. Whether SCN5A plays a role in the pathophysiology of human gut dysmotilities remains to be determined.     

有机阴离子转运蛋白3在人血管平滑肌细胞的表达

目的检测有机阴离子转运蛋白3（OAT3）及其mRNA在人血管平滑肌细胞的表达,并观察尿酸刺激对其表达的影响。方法分离培养人脐动脉血管平滑肌细胞,随机分为正常对照组及尿酸处理组,提取细胞总RNA,RT-PCR方法扩增特异性OAT3 cDNA片段,制备探针,用Northern blot方法检测各组OAT3 mRNA的表达。提取细胞膜蛋白,用Westernblot方法检测各组OAT3的蛋白表达。结果在正常对照组人血管平滑肌细胞可检测到OAT3mRNA和蛋白的表达。与对照组相比,尿酸处理组血管平滑肌细胞OAT3的表达在mRNA及蛋白水平均显著上调（P<0.05,n=3）。结论人血管平滑肌细胞表达OAT3,尿酸处理可以使其表达上调。提示OAT3可能部分介导血管平滑肌细胞对尿酸的摄取过程。     

Inhibitory effect of D3 dopamine receptor on migration of vascular smooth muscle cells induced by synergistic effect of angiotensin II and aldosterone

Abstract

Objective: The abnormal migration of vascular smooth muscle cells (VSMCs) has been implicated to contribute to lesion formation in the adult vasculature. The renin–angiotensin–aldosterone system (RAAS) is intensively involved in the pathogenesis of a variety of cardiovascular diseases. There are increasing pieces of evidence for interactions between RAAS and dopamine receptors. We hypothesize that the D₃ receptor has an inhibitory effect on angiotensin II (Ang II)/aldosterone-induced VSMC migration. Method: In this study, embryonic thoracic aortic smooth muscle cells were cultured. VSMC migration was determined by the Boyden chamber and wound healing assays. Results: VSMC migration was increased by Ang II (10^?10–10^?7 mol/L) in a concentration-dependent manner, but not by aldosterone (10^?10–10^?7 mol/L), and a synergistic effect of Ang II (10^?10 mol/L)/aldosterone (10^?10mol/L) was also observed in VSMC migration. The migratory effects of Ang II alone/with aldosterone were attenuated by the activation of D₃ receptors (10^?10–10^?7 mol/L), although a D₃ receptor agonist, PD128907, by itself, had no effect on VSMC migration. The inhibitory effect of the D₃ receptor on Ang II/ aldosterone-mediated VSMC migration was blocked by the blocker of PKA (14-22 amide, 10^?7 mol/L), indicating that PKA was involved in the signaling pathway. Conclusion: These results indicate that activation of vascular D₃ receptors inhibits Ang II/aldosterone-induced VSMC migration through the PKA signal pathway, which may be important in the regulation of vascular remodeling.     

Activation of natriuretic peptide receptor-C attenuates the enhanced oxidative stress in vascular smooth muscle cells from spontaneously hypertensive rats: implication of Gialpha protein

We have recently shown that vascular smooth muscle cells (VSMC) from spontaneously hypertensive rats (SHR) exhibit enhanced expression of Giα proteins, which was attributed to the enhanced oxidative stress. Since C-ANP_4-23 that specifically interacts with natriuretic peptide C (NPR-C) receptor has been shown to decrease the expression of Giα protein in VSMC, the present study was undertaken to examine if C-ANP_4-23 can also decrease the enhanced expression of Giα protein in VSMC from SHR and whether it is attributed to its ability to attenuate the enhanced oxidative stress. Aortic VSMC from 12-week-old SHR and their age-matched Wistar-Kyoto (WKY) rats were used for the present studies. VSMC from SHR exhibited enhanced expression of Giα-2 and Giα-3 proteins, different subunits of NADPH oxidase such as Nox⁴ and p^47phox proteins but not of p^22phox, enhanced production of superoxide anion as well as NADPH oxidase activity as compared to age-matched WKY rats. Treatment of VSMC from SHR with C-ANP_4-23 decreased towards control levels the enhanced expression of Giα proteins, enhanced superoxide anion production and enhanced NADPH oxidase activity as well as the enhanced expression of Nox⁴ and p^47phox. However, C-ANP_4-23-induced attenuation of the enhanced level of O₂⁻ and NADPH oxidase activity occurs at 4 h before the decrease in the enhanced expression of p^47phox that occurs at 16 h of C-ANP_4-23 treatment. The decreased expression of NADPH oxidase in SHR was also associated with further decrease in O₂⁻ and NADPH oxidase activity. Furthermore, treatment of VSMC from SHR with pertussis toxin (PT) decreased the enhanced levels of superoxide anion as well as NADPH oxidase activity; however, the enhanced levels of different subunits of NADPH oxidase were not attenuated by PT treatment. These results suggest that C-ANP_4-23 decreases the enhanced oxidative stress in SHR by attenuating the enhanced expression of Giα proteins and also the enhanced levels of NADPH oxidase.     

Regulation of force in vascular smooth muscle

Vascular smooth muscle contraction plays a defining role in the regulation and maintenance of blood pressure, and its deregulation is associated with many clinical syndromes including hypertension, coronary vasospasm and congestive heart failure. Over the past 20 years, there has been a growing understanding of the regulation of 20 kDa myosin light chain phosphorylation by myosin light chain kinase and myosin light chain phosphatase, the role of splice-variant isoforms of both the myosin heavy chain and the essential myosin light chain, as well as the signaling pathways involved in smooth muscle contraction under normal and pathophysiological conditions. This review will attempt to recapitulate the data in the field, primarily focusing on the contractile response of smooth muscle, and the molecular determinants responsible for the regulation of vascular tone.     

Th(IV) Adsorption onto Oxidized Multi-Walled Carbon Nanotubes in the Presence of Hydroxylated Fullerene and Carboxylated Fullerene

The adsorption of Th(IV) onto the surface of oxidized multi-walled carbon nanotubes (oMWCNTs) in the absence and presence of hydroxylated fullerene (C₆₀(OH)_n) and carboxylated fullerene (C₆₀(C(COOH)₂)_n) has been investigated. C₆₀(OH)_n, C₆₀(C(COOH)₂)_n and oMWCNTs have been chosen as model phases because of their representative in carbon nano-materials family. Adsorption experiments were performed by batch procedure as a function of contact time, pH, ionic strength, and temperature. The results demonstrated that the adsorption of Th(IV) was rapidly reached equilibrium and the kinetic process could be described by a pseudo-second-order rate model very well. Th(IV) adsorption on oMWCNTs was dependent on pH but independent on ionic strength. Adsorption isotherms were correlated better with the Langmuir model than with the Freundlich model. The thermodynamic parameters calculated from temperature-dependent adsorption isotherms suggested that Th(IV) adsorption on oMWCNTs was spontaneous and endothermic. Compared with the adsorption of Th(IV) on the same oMWCNTs free of C₆₀(OH)_n or C₆₀(C(COOH)₂)_n, the study of a ternary system showed the inhibition effect of C₆₀(OH)_n at high concentration on the adsorption of Th(IV) in a pH range from neutral to slightly alkaline; whereas the promotion effect of C₆₀(C(COOH)₂)_n, even at its low concentration, on Th(IV) adsorption was observed in acid medium.     

高同型半胱氨酸对高血压大鼠血管平滑肌细胞GRP78和CHOP的表达的影响与血管重构的关系

目的：观察同型半胱氨酸（Homocysteine,Hcy）对高血压大鼠内质网应激因子GRP78和CHOP表达及血管中层厚度变化,探讨Hcy对血管重构的影响。方法：采用腹主动脉缩窄术建立高血压大鼠模型,术后两周采用无创尾套法测量大鼠血压,选取24只成年雄性大鼠[平均动脉压（MAP）〉150mmHg]随机等分为2组,即对照组和蛋氨酸组,每组12只（n=12）。对照组给予普通饮食＋双蒸水灌胃,蛋氨酸组给于30g/L蛋氨酸饮食＋双蒸水灌胃;根据实验结束的时间,又将各组分为4W和8W两个亚组,各亚组6只（n=6）。用同型半胱氨酸检测仪检测血清同型半胱氨酸浓度,用颈动脉插管法测定各组大鼠的MAP,并利用图像分析软件测量血管中层的厚度;HE染色观察大鼠主动脉血管形态学变化;通过免疫组化及Western blot检测大鼠主动脉血管平滑肌细胞（VSMCs）组织中GRP78及CHOP表达水平。结果：①对照组大鼠血清Hcy浓度在正常值范围（〈10μmol／L）;蛋氨酸组大鼠血清Hcy浓度明显高于对照组（P〈0．01）。②两组大鼠MAP均显著增高,4周时两者之间差异不明显,8周时两者差异显著（P〈0．05）;③蛋氨酸组大鼠血管平滑肌中层厚度显著大于对照组（P〈0．05）;④HE染色显示,与对照组相比,蛋氨酸组大鼠主动脉VSMCs显著肥大,管壁显著增厚;⑤两组CRP78和CHOP蛋白表达量增高,与对照组相比蛋氨酸组表达更明显。结论：高同型半胱氨酸可能通过促使高血压大鼠动脉VSMCs内质网应激反应,导致CRP78及CHOP的平衡失调加剧,从而引起血管损伤加重,而发生血管重构加重。     

槲皮素及异鼠李素对人血管平滑肌细胞增殖的抑制作用

目的观察槲皮素(QUE)及异鼠李素(ISOR)对培养人血管平滑肌细胞增殖的影响。方法本实验利用培养的人主动脉平滑肌细胞(VSMC),采用细胞计数、3H-胸腺嘧啶核苷酸(3H-TdR)掺入法,观察QUE、ISOR、去甲肾上腺素(NE)对VSMC增殖、DNA合成的影响,以及QUE、ISOR、酚托拉明(Ph)对NE促VSMC增殖、DNA合成的的影响。结果①QUE有明显抑制VSMC增殖、DNA合成的作用,而ISOR作用较弱。在所观察的1～200(滋mol/L的浓度范围内,QUE和ISOR均在200滋mol/L浓度发挥了最大的抑制作用,其抑制作用有剂量依赖关系。②NE有促进VSMC增殖、DNA合成的作用,而这些促进作用能被Ph所阻滞。③QUE和ISOR均剂量依赖地抑制NE促VSMC增殖和DNA合成的作用,且QUE和ISOR有明显的协同作用。④QUE和ISOR对NE刺激作用的抑制明显强于Ph的作用。⑤QUE和ISOR对VSMC无细胞毒作用。结论QUE和ISOR是细胞毒性很低,对VSMC的增殖、DNA合成尤其是对NE刺激的VSMC增殖、DNA合成有很强的抑制作用的天然黄酮类物质。     

Desensitization of platelet-activating factor receptors, induced by inflammation in guinea pig ileal smooth muscle cells

Platelet-activating factor (PAF) is involved in the pathophysiology of motility changes induced by intestinal inflammation. The aim of this study was to evaluate a possible desensitization of PAF receptors in guinea pig intestinal smooth muscle cells after experimental inflammation induced by trinitrobenzenesulfonic acid (TNB). Saline or TNB (80 mg/kg) was injected in the intestinal lumen, and the animals were killed 6 days later. Smooth muscle cells from the circular layer were isolated, and cell contraction induced by PAF was measured. In cells from saline-treated animals, PAF induced a maximal cell contraction at 10 nmol/L and half-maximal contraction (EC₅₀) was 9 ± 0.2 pmol/L. After TNB injection, the maximal contraction induced by PAF was observed at 1000 nmol/L and EC₅₀ was 300 ± 70 pmol/L, indicating a 2 logmol/L right shift of the concentration-response curve of PAF. When animals were treated with the PAF antagonist, 20 mg/kg BN52021, or with 2 mg/kg indomethacin for the 6 days after TNB instillation, the right-sided shift of the concentration-response curve of PAF did not occur. Desensitization of PAF receptors occurring in intestinal smooth muscle cells after TNB instillation could be mediated in vivo by PAF itself via a prostaglandin-dependent pathway.     

Antiproliferative effects of a c-myc antisense oligonucleotide on human arterial smooth muscle cells

Summary The effects of a c-myc antisense phosphorothioate DNA oligonucleotide were assessed on the proliferation rate of human arterial smooth muscle cells (HSMCs). Compared to a control oligonucleotide the antisense oligonucleotide suppressed the proliferation of HSMCs in a concentration-dependent manner without a major cytotoxic effect. Outgrowth of HSMCs from media explants was significantly inhibited as well. Induction of c-myc expression by serum stimulation of cells was blunted by the antisense oligonucleotide, as shown by immunoblotting.These results demonstrate that c-myc expression is an essential factor for proliferation of HSMCs after growth stimulation, and they show the potential of antisense technology for modulating gene expression of HSMCs in vitro.Supported by a grant fromt the SFB 330Results of the study have been presented at the XIIIth Congress of the European Society of Cardiology (1991) and the 64th Scientific Session of the American Heart Association (1991)     

Effects of nitric oxide donors on vascular smooth muscles depend on a type of vascular smooth-muscle preactivation

The abilities of such therapeutic nitrovasodilators as sodium nitroprusside (SNP) and glyceryl trinitrate (GTN) to dilate vascular smooth muscles (VSM) and affect intracellular calcium concentration level ([Ca²⁺]_i) in a rat tail artery were tested under different types of preactivation. To shed light on mechanisms underlying possible differences in the action of these two nitric oxide (NO) donors, simultaneous measurements of [Ca²⁺]_i and contractile force were done. All vascular rings were precontracted either using a high-K⁺-Krebs solution or phenylephrine (PE). It was shown that the effect of both NO donors strongly depended on a type of VSM preactivation. The EC₅₀ for GTN under K⁺ stimulation of VSM comprised (2.48±1.6)×10⁻⁵ M, whereas the mean EC₅₀ under PE stimulation was (3.05±2.3)×10⁻⁴ M (p<0.05, n=9). The EC₅₀ for SNP under K⁺ stimulation of VSM comprised (1.09±0.47)×10⁻⁷ M, whereas the EC₅₀ under PE stimulation was (8.01±2.4)×10⁻⁶ M (p<0.05, n=9). GTN demonstrated a significant discrepancy in the magnitude of changes in [Ca²⁺]_i and related VSM relaxant responses, indicating the ability of GTN to relax VSM in the absence of a proportional decrease in [Ca²⁺]_i. The main peculiarity of SNP action under K⁺ stimulation as compared to PE stimulation was the transient decrease in [Ca²⁺]_i while relaxation was sustained. Therefore, both NO donors demonstrated their ability to produce vasorelaxation as a result of an alteration in myofilament calcium sensitivity. These data clearly indicate that the sensitivity of VSM to NO donors is higher under K⁺ depolarization than that seen under PE stimulation, indicating that Ca²⁺ entry through voltage-operated calcium channels is more sensitive to NO as compared to calcium mobilization by means of Ca²⁺ entry through receptor-operated calcium channels or intracellular Ca²⁺ release, or both.     

高血压大鼠动脉血管平滑肌细胞中GRP78和CHOP表达的变化及对血管重构的影响

目的: 观察高血压大鼠动脉血管平滑肌细胞(VSMCs)内质网应激(ERS)相关因子葡萄糖调节蛋白78(GRP78)和C/EBP同源蛋白(CHOP)的表达、细胞凋亡率和血管中层厚度的变化,探讨ERS对高血压血管重构的影响。方法: 将48只成年雄性SD大鼠随机等分为假手术对照组(对照组)和手术模型组,根据术后结束实验时间的不同,每组又分为3 d、7 d、14 d和28 d 4个亚组,每个亚组6只(n=6)。对大鼠测量血压后,应用免疫组化染色法检测主动脉VSMCs中GRP78和CHOP的表达。采用缺口末端标记法（TUNEL）检测细胞的凋亡;利用图像分析软件测量血管中层的厚度。结果: ①模型组3 d、7 d、14 d和28 d亚组的平均动脉压(MAP),分别为(141.90±9.01)、(150.42±6.29)、(158.00±8.54)和(174.00±8.25) mmHg,均分别高于相应的对照组［(115.06±8.85)、(123.85±9.85)、(118.48±7.60)和(120.08±8.85) mmHg,P<0.05］,且随着时间的延长,血压值逐渐升高。②除模型组3 d亚组外,模型组7 d、14 d和28 d亚组GRP78的表达（A值分别为0.60±0.04、0.85±0.06和0.55±0.06）,均显著高于相应的对照组（A值分别为0.47±0.01、0.47±0.03和0.47±0.02,P<0.01）,于术后14 d达到最高值。③模型组14 d、28 d亚组CHOP的表达（A值分别为0.48±0.04和0.57±0.05）显著高于相应的对照组（A值分别为0.40±0.02和0.40±0.01,P<0.01）,于术后28 d达到最高值;模型组3 d和7 d亚组（A值分别为0.41±0.05和0.41±0.04）与相应的对照组（A值分别为0.39±0.03和0.39±0.03）比较无明显差异。④模型组3 d、7 d、14 d和28 d亚组VSMCs的凋亡率分别为(18.20±0.03)%、(12.00±0.03)%、(6.60±0.02)%和(2.30±0.02)%,与相应的对照组［分别为(21.40±0.04)%、(20.90±0.04)%、(20.50±0.04)%和(21.30±0.04)%］比较有非常显著性差异（P<0.01）。⑤模型组除3 d和7 d亚组血管中层的厚度与相应的对照组比较无明显差异外,模型组14 d和28 d亚组血管中层的厚度［分别为(100.32±2.92) μm和(107.52±5.42) μm］与相应对照组血管中层的厚度［分别为(93.43±2.73) μm和(92.92±3.17) μm］比较有非常显著性差异（P<0.01）。模型组除3 d与7 d亚组中膜的厚度比较无差异外,其余两亚组间中膜的厚度比较有非常显著性差异（P<0.01）。结论: 在高血压发生早期,VSMCs中ERS反应的启动,可导致GRP78及CHOP的表达呈不对称增加,引起细胞凋亡率下降,这可能是血管重构发生的原因之一。     

Ca2+ clearance and contractility in vascular smooth muscle: evidence from gene-altered murine models

The central importance of calcium clearance proteins, and their regulators, in the modulation of myocardial contractility and intracellular Ca²⁺ concentration ([Ca²⁺]_i) has long been established. Key players identified include the Na⁺-Ca²⁺ exchanger, the Na⁺-K⁺ ATPase, the sarco(endo)plasmic reticulum Ca²⁺-ATPase and associated phospholamban. Gene-targeted and transgenic murine models have been critical in the elucidation of their function. The study of these proteins in the regulation of contractile parameters in vascular smooth muscle, on the other hand, is less well studied. More recently, gene-targeted and transgenic models have expanded our knowledge of Ca²⁺ clearance proteins and their role in both tonic and phasic smooth muscle contractility. In this review, we will briefly treat the mechanisms which underlie Ca²⁺ clearance in smooth muscle. These will be addressed in light of studies using gene-modified mouse models, the results of which will be compared and contrasted with those in the cardiomyocyte. The recently identified human mutations in phospholamban, which lead to dilated cardiomyopathy, are also present in vascular and other smooth muscle. Given the importance of these Ca²⁺ clearance systems to modulation of smooth muscle, it is likely that mutations will also lead to smooth muscle pathology.     

血管平滑肌细胞内质网应激与血管钙化的研究进展

血管钙化是指羟基磷灰石沉积于血管壁,由多因素参与及调控,类似于骨、软骨形成的主动生物学过程。内质网应激是机体内适应性调节反应,适当的内质网应激帮助维持内质网稳态,但过度的内质网应激会促进血管钙化的发生与发展。本文综述内质网应激尤其是未折叠蛋白反应在血管钙化中的潜在作用和分子机制,希望为血管钙化的防治提供新的思路。     

拉西地平对高血压大鼠血管平滑肌细胞CRT和caspase12表达变化的影响

目的 探讨压力负荷高血压大鼠动脉血管平滑肌细胞内质网应激相关因子钙网蛋白（calreticulin,CRT）和caspase-12的表达变化及药物拉西地平对其的影响.方法 将30只成年雄性SD大鼠随机等分为对照组（sham组）、模型组（TAC组）和拉西地平组（lacidipine组）.Sham组分离腹主动脉但不行狭窄术,TAC组行腹主动脉狭窄术,lacidipine组行腹主动脉狭窄术并给予拉西地平0.5 mg/（kg·d）,喂养8周用颈动脉插管法测定各组大鼠的平均动脉压（MAP）;利用图像分析软件测量血管中层的厚度;用免疫组织化学法和western-blot法检测CRT和caspase-12的表达水平;TUNEL荧光法检测血管平滑肌细胞的凋亡率.结果 ①TAC组大鼠MAP均值显著高于sham组（P＜0.01＝和lacidipine组（P＜0.05＝;lacidipine组大鼠MAP均值高于sham组（P＜0.05＝;②TAC组大鼠血管平滑肌中层厚度均值大于sham组和lacidipine组均有统计学意义（P＜0.05＝,lacidipine组和sham组大鼠血管平滑肌中层厚度比较,差异无统计学意义（P＞0.05）;③TAC组的CRT和caspase-12蛋白表达量均值高于sham组和lacidipine组,lacidipine组CRT和caspase-12蛋白表达量均值高于sham组（P＜0.05＝;④TAC组大鼠血管平滑肌凋亡率高于sham组和lacidipine组（P＜0.05＝,lacidipine组大鼠血管平滑肌凋亡率高于sham组（P＜0.05＝.结论 腹主动脉狭窄致高血压可引起血管平滑肌细胞内质网应激反应,导致CRT表达增加及caspase-12的活化增高;拉西地平通过下调内质网应激水平,逆转高血压所致的血管平滑肌细胞的损伤作用,对血管平滑肌细胞具有保护作用.