Influence of Angiotensin II on α1-Adrenergic Receptors Function in Rat Aorta and Expression in Vascular Smooth Muscle Cells

Angiotensin II (Ang II) is the main mediator of the Renin-Angiotensin-System acting on AT1 and other AT receptors. It is regarded as a pleiotropic agent that induces many actions, including functioning as a growth factor, and as a contractile hormone, among others. The aim of this work was to examine the impact of Ang II on the expression and function of α1-adrenergic receptors (α1-ARs) in cultured rat aorta, and aorta-derived smooth muscle cells. Isolated Wistar rat aorta was incubated for 24 h in DMEM at 37˚C, then subjected to isometric tension and to the action of added norepinephrine, in concentration-response curves. Ang II was added (1 × 10−5 M), and in some experiments, 5-Methylurapidil (α1A-AR antagonist), AH11110A (α1B-AR antagonist), or BMY-7378 (α1D-AR antagonist), were used to identify the α1-AR involved in the response. Desensitization of the contractile response to norepinephrine was observed due to incubation time, and by the Ang II action. α1D-AR was protected from desensitization by BMY-7378;while RS-100329 and prazosin partially mitigated desensitization. In another set of experiments, isolated aorta-derived smooth muscle cells were exposed to Ang II and α1-ARs proteins were evaluated. α1D-AR increased at 30 and 60 min post Ang II exposure, the α1A-AR diminished from 1 to 4 h, while α1B-AR remained unchanged over 24 h of Ang II exposure. Ang II induced an increase of α1D-AR at short times, and BMY-7378 protected α1D-AR from desensitization.

The Effect of the LysoPC-induced Endothelial Cell Conditioned Medium on Proliferating Cell Nuclear Antigen Expression of the Calf Thoracic Aorta Smooth Muscle Cells

In order to study the effect of and mechanism of lysophosphatidylcholine (LysoPC) on proliferation of the calf thoracic aorta smooth muscle cells (ASMCs), the ASMCs were used to observe the effects of LysoPC induced endothelial cell conditioned medium on the DNA content and proliferating cell nuclear antigen (PCNA) expression in the calf thoracic ASMCs by flow cytometry and Western Blot technique. It was found that LysoPC induced endothelial cell conditioned medium could significantly promote PCNA expression of the calf ASMCs, induce the converting of ASMCs from G 0 /G 1 phase to S phase of DNA synthesis, and increase the tyrosine phosphorylation protein expression. Tyrosine protein kinase inhibitor (TPKi) RG50864 could obviously inhibit proliferation of LysoPC induced ASMCs in a dose dependence manner. The results indicated that the effect of LysoPC promoting the proliferation of ASMCs is partly evoked by endothelial cell derived growth factors such as PDGF and so on.

Morphological Characteristics of Smooth Muscle Cells Isolated from the Rat Ductus Deferens

The aim of this study was to establish a method of isolating and culturing smooth muscle cells from the ductus deferens of rats. Smooth muscle cells were prepared from ductus deferens by explanting technique after dissection of adventitia and intimae, and cultured in vitro. The identification of the smooth muscle cells were verified by using anti u-smooth muscle actin （a-SMA） immunohistochemistry studies. The result suggested that the cells are multi-morphous, showing long fusiform or star shapes. The apophysis of cells contacted and coalesced to each other, in some regions the cells overlapped in multilayer, while in the other regions they formed monolayer that fluctuated and showed a ＂peak-valley＂ shape. They presented a positive reaction through immunohistochemistry studies. The purity of the cells was more than 99% through this method. The culturing of smooth muscle cells by explanting technique is simple and stable.

Overexpression of heme oxygenase-1 protects smooth muscle cells against oxidative injury and inhibits cell proliferation

To investigate whether the expression of exogenous heme oxygenase-1 (HO-1) gene within vascular smooth muscle cells (VSMC) could protect the cells from free radical attack and inhibit cell proliferation, we established an in vitro transfection of human HO-1 gene into rat VSMC mediated by a retroviral vector. The results showed that the profound expression of HO-1 protein as well as HO activity was 1.8- and 2.0-fold increased respectively in the transfected cells compared to the non-transfected ones. The treatment of VSMC with different concentrations of H2O2 led to the remarkable cell damage as indicated by survival rate and LDH leakage. However, the resistance of the HO-1 transfected VSMC against H2O2 was significantly raised. This protective effect was dramatically diminished when the transfected VSMC were pretreated with ZnPP-IX, a specific inhibitor of HO, for 24 h. In addition, we found that the growth potential of the transfected cells was significantly inhibited directly by increased activity of HO-1, and this effect might be related to decreased phosphorylation of MAPK. These results suggest that the overexpression of introduced hHO-1 is potentially able to reduce the risk factors of atherosclerosis, partially due to its cellular protection against oxidative injury and to its inhibitory effect on cellular proliferation.

Effects of Total Flavonoids ofHippophae RhamnoidesL.on Intracellular Free Calciumin Cultured Vascular Smooth Muscle Cells of Spontaneously Hypertensive Rats and Wistar-Kyoto Rats

To explore the effects of total flavonoids of Hippophae rhamnoides L. （TFH） quercetin （Que） and isorhamnetin （Isor） on the intracellular free calcium （[Ca^2＋]） in vascular smooth muscle cells （VSMC） of spontaneously hypertensive rats （SHR） and Wistar-Kyoto rats （WKY）. Metheds： Fluo 3-acetoxymethylester（Fluo-3/AM） was used to observe the effects of TFH （100mg/L） and its essential monomers, namely Que （10^-4mol/L） and Isor （10^-4mol/L） on changes of [Ca^2＋]1 in cultured SHR and WKY VSMC （abbr. to Ca-SHR ＆ Ca-WKY） following exposure to high K^＋, norepinephrine （NE） and angiotensin Ⅱ （AngⅡ）, and to compare with the effects of verapamil （Ver）. Results： （1） TFH, Que and Isor had inhibitory effects on resting Ca-SHR （P〈0.05）, but had no significant effects on Ca-WKY （P〉0.05）. （2） High K^＋ could increase Ca-SHR more significantly than Ca-WKY （P〈0.05）; TFH, Que and Isor could inhibit the elevation of [Ca^2＋]1 induced by high K^＋ -depolarization, with the effects similar to that of Ver, and the effect on Ca-SHR was more significant than that on Ca-WKY （P〈0.05）. （3） NE and Ang Ⅱ could increase Ca-SHR more significantly than Ca-WKY （P〈0.05）, TFH, Que and Isor had remarkably inhibitory effect on the elevation of Ca-SHR and Ca-WKY induced by NE or Ang Ⅱ. （4） In the absence of extracellular Ca^2＋ , TFH, Que and Isor also had certain inhibitory effect on Ca-SHR and Ca-WKY induced by NE, and the effect on the former was more significant than that on the latter（P〈0.05）. Ceaclusiea： TFH, Que and Isor might decrease the levels of [Ca^2＋], in VSMCs by blocking both voltage-dependent calcium channels （VDC） and receptoroperated calcium channels （ROC） in physiological or pathological state, which may be one of the important mechanisms of their hypotensive and protective effects on target organs in patients with hypertension.

Study of the structure and architecture of aortic smooth muscle cells under pressure overloading in rats

Male Wistar rats were used to study the changes of the structure and architecture of the smooth muscle cells(SMCs) of the aorta under pressure overloading(PO).The aorta was cut open longitudinally and the tunica media was examined with a histological tech

Lamin A/C Modulate Apoptosis of Rat Vascular Smooth Muscle Cells During Cyclic Stretch Application

Objective The apoptosis of vascular smooth muscle cells(VSMCs)influenced by abnormal cyclic stretch is crucial for vascular remodeling during hypertension.We explored that the causes of mechano-responsive lamin A/C changingin aonormai cyclic stretcn and its roles in VSMC apoptosis.Methods and results Our previous vascular proteomics study revealed that LaminA/C is mechano-sensitive molecule.When VSMCs are subjected to cyclic stretch,the expression of LaminA/C is significantly changed which participates dysfunctions of VSMCs during hypertension.However,the molecular mechanism involved in regulation of LaminA/C expression and the role of LaminA/C in the VSMC apoptosis during cyclic stretch application are still unclear.In the present study,VSMCs were subjected to different amplitudes of cyclic steetch in vitro:5%cyclic stretch(physiological strain)or 15%cyclic stretch(pathological strain).The expression of 2 different selective cleavage isomers of LaminA/C,i.e.LaminA and LaminC,and the apoptosis of VSMCs were detected.The results showed that compared with 5%group,15%cyclic stretch significantly decreased the expression of LaminA and LaminC,and promoted the apoptosis of VSMCs.Using specific small interfering RNA(siRNA)transfection which targets on LMNA the encoding gene of LaminA/C,the expression of LaminA and LaminC in VSMCs was significantly decreased,and the apoptosis was significantly increased.In order to study the molecular mechanism involved in cyclic stretch regulating the expression of LaminA/C,we focused on the microRNA(miR).Bioinformatics analysis showed that the 3’untranslated region(3’UTR)of LMNA has two potential binding sites to miR-124-3p.Double luciferase reported system revealed that both sites have binding abilities to miR-124-3p.Under static condition,miR-124-3p inhibitor significantly up-regulated the expression levels of LaminA and LaminC,while the miR-124-3p mimics significantly down-regulated them.RT-PCR results showed that 15%cyclic stretch significantly up-regulated the expression of miR-124-3p compared with 5%cyclic stretch.Furthermore,in order to study the role of changeed LaminA/C in VSMC apoptosis,LMNA-specific siRNA was transfected to repress the expression of LaminA/C in VSMCs,and Protein/DNA microarray was used to detecte the activity of transcription factors.The transcription factors whose activity were changed significantly(increase or decrease more than 2 times)were analyzed by cluster analysis and ingenurity pathway analysis(IPA).Six transcription factors associated with apoptosis were screened,in which TP53 was activated by the specific siRNA transfection and the other 5 were inavtived,including TP53,CREB1,MYC,STAT1/5/6 and JUN.Using abdominal aorta coarctation hypertensive model,the change of miR-124-3p in VSMCs was explored in vivo.A marked increase of miR-124-3p in thoracic aorta was revealed compared with the sham-operated controls,and in situ FISH revealed that this increase was mainly in the VSMCs.Conclusions The present study suggest that abnormally increased cyclic stretch(15%)up-regulates the expression of miR-124-3p in VSMCs,which subsequently targets on the 3’UTR of LMNA and decreases the expression of nuclear envelope protein LaminA/C;the repressed LaminA/C may play an important role in the apoptosis of VSMCs by regulating the activity of virious transcription factors,such as TP53,CREB1,MYC,STAT1/5/6 and JUN.The present study may provide a new insight into understanding the molecular mechanisms of vascular remodeling.

Expression of Inositol 1,4,5-trisphosphate Receptor mRNA in Myocardium of Spontaneous Hypertension Rats and Cultured Vascular Smooth Muscle Cells of Rats

Objective\ To investigate expression of inositol 1,4,5 trisphosphate receptor (IP\-3R) mRNA on sacroplasmic reticular in myocardium of spontaneous hypertension rats (SHRs) and cultured vascular smooth muscle cells (VSMC) of rats and effects of perindopril and urapidil on them. Methods\ SHRs were orally given perindopril (1.0 mg·kg\+\{ 1\}·d\+\{ 1\}) or urapidil (15 mg·kg\+\{ 1\}·d\+\{ 1\}) for 24 weeks, respectively. Expression of IP\-3R mRNA was examined by semi quantitative reverse transcription polymers chain reaction (RT PCR) using three oligonuclotide primers for each subtype of IP\-3R with β actin as internal label. Results\ All subtypes of IP\-3R were expressed in myocardium of SHR, WKY and cultured VSMC. Expression of IP\-3R mRNA in left ventricle of SHR was markedly enhanced. Urapidil could down regulate expression of IP\-3R Ⅰand IP\-3R Ⅲ, perindopril slightly increased expression of IP\-3R Ⅱ and decreased expression of IP\-3R Ⅰand IP\-3R Ⅲ in myocardium of SHR. Conclusion\ Our results suggest that expression of IP\-3R mRNA in cardiovascular system could be regulated by urapidil and perindopril.

Effects of estradiol on cell cycle and cyclin proteins of vascular smooth muscle cells in rats

To study the effects of 17β-estradiol(E2) on the growth of cultured rat vascular smooth muscle cells (VSMC).Methods The cell cycle and the expressions of Cyclin D1 and CDK4 proteins were examined by flow cytometry in VSMC cultured in different concentrations (0～100 nmol/L) of 17β-estradiol with or without serum.Results Under serum-stimulating conditions,17β-estradiol(1,10,100 nmol/L) promoted VSMC proliferation by accelerating their cell cycle progression from G1 to S phases,and the cell rates at S were (31.89±9.14)%(35.90±4.59)% and (30.77±1.20)% respectively,significantly higher than the corresponding values of control cells (21.63±1.80)%.This was accompanied by the significantly increased expression of Cyclin D1 and CDK4 proteins.In the cultures without serum,however,high concentrations (10,100 nmol/L) of E2 induced a cell cycle arrest at G1 phase,which was characterizsed by decreased cell rates at S phase [(9.93±1.43)% and (8.76±1.80)% respectively,P<0.05] as compared with the corresponding control values and a down-regulation of expressions of Cyclin D1 and CDK4 proteins.Conclusion E2 can either promote or inhibit VSMC proliferation depending upon the presence or absence of serum mitogens.The underlying mechanism may be associated with the hormone’s action on the expression of Cyclin D1 and CDK4 which act as the G1 phase regulators.4 refs.

Endothelin-1, an important mitogen of smooth muscle cells of spontaneously hypertensive rats

OBJECTIVE: To study the features of vascular smooth muscle cell (VSMC) proliferation induced by endothelin-1 (ET-1). METHODS: VSMCs of spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats were cultured and treated with ET-1. Basic fibroblast growth factor (bFGF) gene expression was measured using both Northern blot and an enzyme-linked immunoassay. RESULTS: ET-1 resulted in an increase in bFGF transcripts at 8 - 24 h; bFGF levels were significantly higher in VSMCs treated with ET-1 than in those not treated. However, VSMCs growth responses in SHR and WKY were different. Smooth muscle cells of SHR were hyper-responsive to ET-1. Maximal bFGF mRNA levels were elevated 3.5-fold at 4 h of stimulation in WKY and 8-fold at 8h in SHR4. Moreover, the proliferation of VSMCs induced by ET-1 was inhibited by antisense phosphorothioate oligodeoxynucleotides (10 micromol/L AS-bFGF) but not sense bFGF oligomers at the same concentrations, being reduced by 80% in SHR and 40% in WKY vs control, respectively. Furthermore, the effect of AS-bFGF oligomers on SHR SMC proliferation is significantly greater than on WKY SMC proliferation. CONCLUSION: ET-1 may be required for exaggerated vascular growth responses in SHR and bFGF may be involved.

Inhibitory effect of trapidil on proliferation of cultured rat aortic smooth muscle cells induced by endothelin-1

目的：观察曲匹地尔（Ｔｒａ）对内皮素１诱导的血管平滑肌细胞（ＶＳＭＣ）增生的影响．方法：测定ＶＳＭＣ数目，［３Ｈ］ＴｄＲ参入细胞ＤＮＡ的放射活性及ＶＳＭＣ的细胞周期分布．结果：内皮素１１００ｎｍｏｌ·Ｌ－１处理大鼠ＶＳＭＣ后，细胞数，［３Ｈ］ＴｄＲ摄取及细胞分裂增殖活性等分别增加１３４％±２３％，２１２％±７１％和８６％±１８％，Ｔｒａ５，５０，５００μｍｏｌ·Ｌ－１对上述参数的抑制率分别为１２％－４８％，３５％－５４％和１５％－４７％．Ｔｒａ５０μｍｏｌ·Ｌ－１和５００μｍｏｌ·Ｌ－１对未经内皮素处理的细胞的生长无明显作用．结论：Ｔｒａ对内皮素１诱导的培养大鼠ＶＳＭＣ的增生具有阻抑作用．

Proliferation of aortic smooth muscle cells and renin-angiotensin system in SHR rats

目的：探讨ＳＨＲ大鼠主动脉平滑肌细胞（ＡＳＭＣ）异常增殖和肾素血管紧张素系统（ＲＡＳ）的关系．方法：测定血管紧张素Ｉ（Ａｎｇ）、卡托普利（Ｃａｐ）、沙拉新（Ｓａｒ）对培养的ＳＨＲ、ＷＫＹＡＳＭＣ增殖和Ａｎｇ、血管紧张素转化酶（ＡＣＥ）的影响．结果：Ａｎｇ在２％血清培养基中可刺激ＳＨＲＡＳＭＣ增生．ＳＨＲＡＳＭＣ分裂增殖能力比ＷＫＹ强，ＳＨＲＡＳＭＣＲＡＳ处于高功能状态．Ｃａｐ长期（４周）干预显著抑制ＳＨＲＡＳＭＣ异常增殖和Ａｎｇ、ＡＣＥ活性，Ｓａｒ长期干预同样抑制ＳＨＲＡＳＭＣ的增殖和ＡＣＥ活性，但Ａｎｇ水平反而升高．Ｃａｐ短期（２４小时）干预不影响两种大鼠ＡＳＭＣＲＡＳ．结论：Ｃａｐ和Ｓａｒ长期干预通过减少ＳＨＲＡＳＭＣＡｎｇ生成或阻断Ａｎｇ和特异受体结合，抑制其异常增殖．

Activated focal adhesion kinase involved in adhesion and migration of vascular smooth muscle cells stimulated by fibronectin

OBJECTIVE: To study the effects of focal adhesion kinase (FAK) phosphorylation on smooth muscle cells (SMCs) adhesion and migration stimulated by fibronectin. METHODS: Adhesion and migration of cultured SMCs were stimulated by different concentrations of fibronectin (FN), FAK and its phosphorylation were detected by immunoprecipitation and Western blot. FAK antisense oligodeoxynucleotides (ODNs) were transfected into SMCs by cationic lipid to investigate its modulatory effects on tyrosine phosphorylation. SMCs adhesion and migration were also measured by morphological enumeration and modified Boyden Chambers, respectively. RESULTS: FAK were expressed when SMCs adhesion and migration were successfully simulated by different concentrations of FN. FAK phosphorylation were detected only at 20 microg/ml FN or more. FAK antisense ODNs were transfected efficiently by cationic lipid and FAK phosphorylation was inhibited substantially. The SMCs migration rate in the 5 - 60 microg/ml FN groups was reduced by 17.89% - 27.67%. Cell migration stimulated by FN at 10, 20, 40 and 60 microg/ml were reduced by 23.26%, 21.63%, 19.31% and 17.88%, respectively (P

Inhibitory effect of antisense basic fibroblast growth factor oligonucleotides on proliferation of cultured aortic smooth muscle cells induced by angiotensin Ⅱ in SHR rats

目的：研究转染反义碱性成纤维细胞生长因子（ｂＦＧＦ）寡核苷酸（ＯＤＮ）对培养的自发性高血压大鼠（ＳＨＲ）主动脉平滑肌细胞（ＳＭＣ）生长的影响．方法：用脂质体介导法将反义ｂＦＧＦＯＤＮ转入ＳＭＣ内，用Ｎｏｒｔｈｅｒｎ杂交检测ｂＦＧＦ基因表达，并测定［３Ｈ］ｔｈｙｍｉｄｉｎｅ掺入和细胞计数．结果：转染反义ｂＦＧＦＯＤＮ（５μｍｏｌ·Ｌ－１）几乎完全抑制血管紧张素Ⅱ（ＡｎｇⅡ，１μｍｏｌ·Ｌ－１）诱导增高的ｂＦＧＦｍＲＮＡ表达和明显抑制ＳＭＣ增殖，在基础状态和ＡｎｇⅡ刺激条件下，［３Ｈ］ｔｈｙｍｉｄｉｎｅ掺入分别被抑制２６５％（Ｐ＜００１）和４２０％（Ｐ＜００１），细胞数分别被抑制１７３％（Ｐ＜００１）和２２２％（Ｐ＜００１）．结论：反义ｂＦＧＦＯＤＮ能有效抑制ＡｎｇⅡ诱导的ｂＦＧＦ基因表达和ＳＭＣ增殖．

Effects of Total Alkaloids in Buxus microphylla Leaves on Aorta Smooth Muscle of Rats and Their Mechanisms

Objective To investigate the effects of total alkaloids in Buxus microphylla leaves(ABML)on isolated rats thoracic aorta rings,and then to explore the possible mechanisms underlying the effects.Methods Thoracic aortas of Wistar rats were isolated,removed,and mounted onto an organ bath.The effects of ABML at different concentration on the contraction of isolated thoracic aorta rings(with and without endothelium)precontracted with KCl or PE were observed with organ bath technique.Dose-effect curves of CaCl2 were recorded by organ bath technique.The concentration of intracellular Ca 2+ ([Ca 2+ ]i)increased by PE,KCI,and caffeine in the presence of ABML was determined using Ca 2+ sensitive fluorescence indicator Fura-2/AM loaded thoracic aorta vascular smooth muscle (VSM)cells of rats.Results In aorta rings precontracted with PE and KCl,ABML produced concentration- dependent relaxation in both intact and denuded endothelium ring groups.There was no difference in the inhibition of contraction between the intact and denuded endothelium ring groups at the same concentration.Exposure of isolated thoracic aorta rings to ABML led to a significant reduction in the contracting response induced by CaCl2,and shifted the cumulative concentration-response curves to right.ABML could significantly inhibit the extracellular Ca 2+ influx induced by PE and KCl under[Ca 2+ ]0 of 1.5 mmol/L,with inhibitory ratios of 40.2%and 49.9%,respectively.In the case of Ca 2+ -free,ABML could significantly inhibit the intracellular Ca 2+ release induced by PE,with inhibitory ratio of 72.4%.Conclusion ABML relaxes thoracic aorta VSM cells by suppressing influx of extracellular Ca 2+ via voltage-dependent Ca 2+ channel and receptor-operated Ca 2+ channel.

Different Concentrations of Notoginsenoside Rg1 Attenuate Hypoxic and Hypercapnia Pulmonary Hypertension by Reducing the Expression of ERK in Rat PASMCs

Pulmonary arterial hypertension (PAH) is a serious disease which is characterized by increased vascular resistance and pressure. We have previously hypothesized that panax notoginseng saponins (PNS) might attenuate pulmonary vasoconstriction under hypoxia and hypercapnia condition. This study aims to investigate the effect of notoginsenoside Rg1, a main ingredient of PNS, with various concentrations (8, 40, 100 mg/L, respectively) on extracellular signal regulated kinase (ERK1/2) signaling pathway in pulmonary arterial smooth muscle cells (PASMCs). In addition, PASMCs were randomly divided into six groups: SD rat under normoxic condition as control group (N group), hypoxia hypercapnia group (H group), DMSO control group (HD group), Rg1-treatment groups (RgLRgM and RgH group). Western-blot and RT-PCR were used to test the expression of p-ERK protein and the expression of ERK1 mRNA and ERK2 mRNA. This study provided the evidence that the expression of p-ERK protein and the expression of ERK1 mRNA and ERK2 mRNA in HD group and H group were obviously higher than that in N group (P < 0.01), Whereas the level of ERK1/2 mRNA in Rg1-treatment groups was significantly lower than that in HD group and H group (P < 0.01), and the proper concentration of Rg1 is 40 mg/L. These results suggested that notoginsenoside Rg1 can attenuate pulmonary vasoconstriction which may lead to HHPV through reducing the expression of ERK1/2.

SHORT COMMUNICATIONS Comparison of inositol phosphates formation and gene expression of Gq alpha subunit in cultured aortic smooth muscle cells from spontaneously hypertensive and Wistar Kyoto rats

Abstract Objecitve To explore whether phosphoinositide specific phospholipase C (PLC) activation via G protein in vascular smooth muscle cells (VSMCs) is altered in spontaneously hypertensive rats (SHR). Methods The VSMCs derived from aortae of SHR and Wistar Kyoto (WKY) rats were loaded for 48 hours with myo inositol. Inositol phosphate release was initiated by the addition of 10 5 mol/L norepinephrine in intact cells or by guanosine 5' 0 (3 thio tri sphosphate) (GTP gamma S) in permeabilized cells. In the meantime, growth arrested VSMCs were stimulated by 10% calf serum for 0, 30, 45, or 60 min, then gene expressions of Gq alpha subunit (G alph a q) were observed. Results There were no significant differences in inositol 1, 4,5 triphosphate (IP 3) level and expression of G alpha q mRNA between quiescent VSMCs from SHR and that from WKY. When stimulated by norepinephrine, IP 3 production increased transiently with a peak level at 10 s in VSMCs from WKY, and a rapid biphasic IP 3 response, which was significantly higher than that of WKY, in VSMCs from SHR had been observed. G proteins activated by GTP gamma S significantly raised IP 3 production in VSMCs from SHR compared to WKY (SHR vs WKY: 234.8%±29.2% vs 142.4%±12.0% of basal IP 3, P<0.05). In addition, the serum effect showed an significant increase in expression of G alpha q mRNA in VSMCs from SHR. Conclusions The hereditary factors are not the only variable regulating IP 3 metabolism and G alpha q gene expression. Influences of multi environmental factors such as vasoactive compounds, together with genetic predisposition, palys an important role in the highly sensitive response of IP 3 production and G alpha q gene over expression in SHR.

Oxidized low-density lipoproteins induce apoptosis in vascular smooth muscle cells

目的：研究氧化型低密度脂蛋白（ｏｘＬＤＬ）诱导血管平滑肌细胞凋亡．方法：梯度超速离心分离血浆ＬＤＬ，以ＣｕＳＯ４１０μｍｏｌ·Ｌ－１氧化，观察ｏｘＬＤＬ对培养兔胸主动脉平滑肌细胞的损伤作用．Ｈｏｅｃｈｓｔ３３２５８荧光染色观察形态学改变，抽提细胞ＤＮＡ进行琼脂糖凝胶电泳．结果：ｏｘＬＤＬ３００ｍｇ·Ｌ－１与ＶＳＭＣ共温育２４ｈ诱导典型的凋亡形态学变化和ＤＮＡ降解，但天然低密度脂蛋白无此作用．当ｏｘＬＤＬ为４００ｍｇ·Ｌ－１或温育时间延至４８ｈ，上述变化更加明显．硫酸葡聚糖２０ｍｇ·Ｌ－１和ＢＨＴ５０μｍｏｌ·Ｌ－１对此作用无影响．ＬＰＣ１２５μｍｏｌ·Ｌ－１无诱导凋亡作用．结论：ｏｘＬＤＬ诱导血管平滑肌细胞凋亡，氧自由基和ＬＰＣ不参与这一过程．

Effects of Ro 31-8220 on smooth muscle cell proliferation induced by fibrinogen degradation products

目的：研究纤维蛋白原降解产物的致有丝分裂原活性及一种新型ＰＫＣ抑制剂Ｒｏ３１８２２０（Ｒｏ）的作用．方法：大鼠主动脉平滑肌细胞增殖采用结晶紫染色法测定．结果：纤维蛋白原降解产物促进大鼠主动脉平滑肌细胞的增殖，Ｒｏ（００１－１μｍｏｌ·Ｌ－１）剂量依赖地抑制增殖．结论：Ｒｏ抑制纤维蛋白原降解产物诱导的平滑肌细胞的增殖．