ERK1/2及JNK参与DL0805抑制血管紧张素Ⅱ引起的大鼠离体胸主动脉环收缩

目的研究Rho激酶抑制剂DL0805对血管紧张素Ⅱ(AngⅡ)引起的大鼠离体胸主动脉环收缩反应的影响及其可能的机制。方法测定离体血管张力观察大鼠胸主动脉环收缩反应,Western blot检测大鼠离体胸主动脉环ERK1/2和JNK蛋白磷酸化,和AngⅡ1型受体(AT1R)蛋白表达水平。结果 DL0805(10、25和50μmol/L)浓度依赖性地抑制AngⅡ(100 nmol/L)引起的内皮完整或去内皮的大鼠离体胸主动脉环收缩(P<0.01,P<0.001),DL0805(25和50μmol/L)抑制AngⅡ(100 nmol/L)诱导的ERK1/2和JNK的活化(P<0.05,P<0.01和P<0.001),但DL0805(5、25和50μmol/L)对AngⅡ刺激的血管环AT1R蛋白表达水平无显著影响。结论 DL0805抑制AngⅡ引起的大鼠离体胸主动脉环收缩,其机制可能与其抑制AngⅡ诱导的ERK1/2和JNK活化有关。     

血管紧张素Ⅱ2型受体对大鼠血管平滑肌增殖的影响及其机制

目的：观察血管紧张素Ⅱ（AngⅡ）2型受体（AT2R）对培养的大鼠血管平滑肌细胞 （VSMC）增殖的影响。方法： 将AT2R cDNA转染到培养的大鼠VSMC中， 分别观察AngⅡ、AngⅡ＋losartan、AngⅡ+PD123319等不同处理因素处理对VSMC的 细胞数目以及PCNA、 NOS表达的影响。 结果：losartan 处理组细胞数目和PCNA表达量少于AngⅡ处理组，NOS表达量高于AngⅡ处理组， 而PD123319处理组细胞数目和PCNA表达量显著高于AngⅡ处理，NOS表达量较之为少。结论： 激活AT2R能拮抗AngⅡ的由AT1R介导的促细胞增殖作用，这种作用可能与激活AT2R后NOS表达增多使 NO合成增多有关。     

氯沙坦对糖尿病大鼠肾小管间质p38MAPK和TGF-β1表达的影响

目的：研究血管紧张素ⅡⅠ型受体拮抗剂（AT1RA）氯沙坦对糖尿病大鼠肾小管间质p38激活丝裂原活化蛋白激酶（p38MAPK）和转化生长因子-β1（TGF-β1）表达的影响。方法:建立STZ诱导的糖尿病(DM)大鼠模型，设正常对照组(NC)、糖尿病组(DM)和氯沙坦治疗组(DT)。用免疫组化和RT-PCR方法观察肾小管间质p38MAPK和TGF-β1蛋白及其mRNA表达。结果:p38MAPK和TGF-β1在DM大鼠肾小管间质的表达较正常对照组显著升高（P<0.05），氯沙坦治疗组与同期糖尿病组相比明显降低（P<0.05）。结论:氯沙坦降低糖尿病大鼠肾小管间质p38MAPK和TGF-β1的表达，缓解肾小管间质病理改变。     

CTGF反义寡核苷酸对血管紧张素Ⅱ诱导的心肌成纤维细胞增殖、胶原合成的抑制效应

目的：研究结缔组织生长因子（CTGF）反义寡核苷酸对血管紧张素Ⅱ诱导的心肌成纤维细胞增殖、胶原合成及CTGF表达的抑制作用。 方法： 差速贴壁法分离新生SD大鼠心肌成纤维细胞(CFs)。反义、正义、错义CTGF寡核苷酸分别经阳离子脂质体介导转染CFs，并与血管紧张素Ⅱ(AngⅡ)10-6mol/L共培养48 h，采用MTT法测CFs生长数目，羟脯氨酸法测胶原蛋白含量，RT-PCR法及Western blotting法分别测CTGF mRNA及蛋白水平的表达。 结果： AngⅡ可以在mRNA及蛋白水平明显促进CFs CTGF的表达(P<0.01)，且呈浓度-时间依赖性。CTGF反义链组的MTT反应A值、胶原蛋白含量、CTGF mRNA及蛋白水平的表达量均明显低于AngⅡ组（P<0.01），而CTGF正义链组和错义链组与AngⅡ组无显著差异(P>0.05)。 结论： AngⅡ刺激下产生的CFs CTGF mRNA和蛋白水平的表达上调，可能是心肌纤维化传导通路中的关键环节，CTGF反义寡核苷酸可以序列特异性地阻断CTGF的介导，从而抑制AngⅡ对心肌成纤维细胞增殖、胶原合成及CTGF表达的诱导作用，进一步证实CTGF可能是拮抗心肌纤维化的特异性靶位。     

血管紧张素Ⅱ激活巨噬细胞株p38MAPK信号通路并诱导其增殖

目的：探讨血管紧张素Ⅱ(AngⅡ)激活巨噬细胞p38MAVK信号通路的模式变化及其对巨噬细胞株增殖的影响。方法：用Western blot测定细胞p38MAPK磷酸化表达；用细胞免疫组化观察细胞p38MAPK激活后核移位；用MTT法观察细胞增殖。结果：AngⅡ(1μmol／L)可诱导RAW264．7细胞p38MAVK磷酸化表达，15～30分钟达到高峰，随时间呈峰形变化。AngⅡ呈剂量依赖性诱导RAW264．7细胞p38MAPK磷酸化。p38MAPK特异性抑制剂SB202190可显著抑制RAW264．7细胞p38MAVK磷酸化，并呈剂量依赖性。AngⅡ可诱导RAW264．7细胞增殖，SB202190可显著抑制AngⅡ诱导的RAW264．7细胞增殖。结论：AngⅡ可激活RAW264．7巨噬细胞株p38MAPK信号通路，并通过p38MAPK信号通路调控RAW264．7细胞增殖。     

血管紧张素Ⅱ 1型受体拮抗剂抑制动脉损伤后中膜平滑肌细胞血小板源性生长因子的表达及细胞迁徙

目的： 研究球囊导管损伤后早期血管紧张素Ⅱ1型受体（AT1）拮抗剂对损伤后大鼠动脉中膜平滑肌细胞血小板源性生长因子（PDGF）的表达及细胞迁徙影响。方法： 12周雄性Wistar大鼠颈动脉用球囊导管损伤，分成实验组和对照组，分别于术前2 d给予血管紧张素Ⅱ1型受体拮抗剂CV-11974（5 mg·kg-1·d-1）和溶剂，术后2 d、3 d、5 d和14 d处死。用原位杂交、免疫组织化学和病理组织学进行研究。结果： 实验组术后第2 d、3 d和5 d中膜平滑肌细胞PDGF-A mRNA和PDGF-A、PDGF B、PDGF-α（R）、β（R）阳性细胞率以及迁徙率明显低于对照组（P<0.01）。实验组的中膜平滑肌细胞表型处于收缩型。结论： 血管紧张素Ⅱ1型受体拮抗剂明显抑制损伤后动脉中膜平滑肌PDGF及其受体的表达和平滑肌迁徙。     

重组反义AT1R腺病毒对人血管平滑肌细胞增殖和凋亡的影响

为探讨腺病毒介导反义人AT1R转染对培养的人血管平滑肌细胞 (VSMCs)增殖和凋亡的影响 ,用重组反义人AT1R的复制缺陷型腺病毒 (Ad CMV ahAT1)转染体外培养的人VSMCs,用RT PCR和免疫组化法检测AT1R的表达 ,用流式细胞仪检测VSMCs的增殖指数和凋亡率 ,绘制DNA合成直方图。结果显示 :与对照组比较 ,转染Ad CMV ahAT1后 4 8h的VSMCs,AT1RmRNA低 5 0 % ,AT1R蛋白呈低表达 (P <0 0 1) ;给予AngⅡ刺激的VSMCs的增殖指数明显增加 (与DMEM组比 ,P <0 0 1) ,转染Ad CMV ahAT1组的增殖指数则显著降低 (与DMEM组比P <0 0 5 ,与AngⅡ对照组比P <0 0 1)。Ad CMV ahAT1组在二倍体峰之前出现凋亡峰 ,各时相点细胞凋亡率分别为 18%(6h)、2 0 % (12h)、2 8% (2 4h)、2 6 % (4 8h)、3% (72h)和 1% (96h) ,而在其它各对照组未出现凋亡峰。这些提示腺病毒介导的反义人AT1R转染 ,通过抑制AT1R的表达 ,明显抑制人VSMCs的增殖和AngⅡ刺激的人VSMCs增殖 ,并诱导VSMCs凋亡。     

尾加压素Ⅱ通过ERK1/2途径诱导大鼠肺动脉平滑肌细胞增殖和上调Egr-1表达

 目的:研究不同浓度尾加压素Ⅱ（UⅡ）及其受体拮抗剂urantide对培养大鼠肺动脉平滑肌细胞（PASMC）增殖的影响,探讨丝裂原活化蛋白激酶（MAPK）途径及早期生长反应因子1（Egr-1）在UⅡ诱导大鼠PASMCs增殖中的作用。 方法: 以组织贴块法原代培养大鼠PASMCs：(1) 采用BrdU掺入实验测定不同浓度（1 μmol/L、0.1 μmol/L和0.01 μmol/L）UⅡ及其受体拮抗剂对大鼠PASMCs 增殖的影响;(2) 采用real-time PCR检测UⅡ及其受体拮抗剂对细胞外信号调节激酶1/2 (ERK1/2)、应激活化蛋白激酶（SAPK）、p38 MAPK及Egr-1 mRNA 表达的影响;(3) 采用Western blotting检测UⅡ、urantide及ERK1/2抑制剂PD98059对PASMCs磷酸化ERK1/2（p-ERK1/2）、p-SAPK、p-p38 MAPK和Egr-1蛋白表达的影响。 结果: （1）UⅡ在一定浓度范围（1 μmol/L、0.1 μmol/L和0.01　μmol /L）呈浓度依赖性地促进肺动脉平滑肌细胞增殖(P＜0.01或P＜0.05),这种增殖作用可被urantide拮抗(P＜0.05);（2）UⅡ上调ERK1/2、SAPK及Egr-1 mRNA表达(P＜0.01或 P＜0.05),PD98059和(或)urantide可拮抗UⅡ诱导的ERK1/2、SAPK和Egr-1 mRNA的表达(P＜0.01或 P＜0.05),但对p-p38 MAPK无影响;（3）UⅡ可增加PASMCs p-ERK1/2、p-SAPK及Egr-1蛋白表达(P＜0.01或 P＜0.05),urantide及PD98059可拮抗UⅡ诱导的p-ERK1/2、p-SAPK和Egr-1蛋白表达(P＜0.01, P＜0.05)。 结论: UⅡ可能通过ERK1/2途径诱导PASMCs增殖和上调Egr-1表达,Egr-1可能通过激活ERK1/2途径参与了PASMCs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。     

Cx40和Cx43调节大鼠肠系膜上动脉收缩反应性与钙敏感性的机制

目的：研究连接蛋白Cx40/Cx43对大鼠肠系膜上动脉内膜依赖的血管收缩反应性与钙敏感性的调节作用机制。方法:以SD大鼠肠系膜上动脉（SMA）为研究对象，用Cx40或Cx43反义寡脱氧核苷酸（Cx40/Cx43AODN）阻断SMA Cx40或Cx43表达，观察缺氧处理后SMA的收缩反应性、钙敏感性、肌球蛋白轻链磷酸酶/激酶（MLCP/MLCK)的活性、20 kD的肌球蛋白轻链（MLC₂₀）磷酸化程度的变化。结果:Cx40AODN可以降低正常组、1 h和3 h缺氧组SMA MLCP活性，增加MLC₂₀磷酸化水平，改善血管的钙敏感性和内膜依赖的收缩反应性；Cx43AODN可以增加各组血管的MLCP活性，减少MLC₂₀磷酸化水平，降低血管的钙敏感性和内膜依赖的收缩反应性。Cx40和Cx43AODN对SMA MLCK活性无明显作用。结论:Cx40和Cx43主要通过调节血管平滑肌细胞的MLCP活性和MLC₂₀磷酸化水平调节血管的钙敏感性，从而调节休克后内膜依赖的血管收缩反应性。     

Difference in signal transduction mechanisms involved in 5-hydroxytryptamine- and U46619-induced vasoconstrictions.

In order to elucidate the signal transduction pathways of vascular smooth muscle contractions induced by stimulation of receptors for 5-hydroxytryptamine (5-HT) and thromboxane A2 (TXA2), both of which are released from activated platelets, we examined whether protein kinases, such as tyrosine kinase, p38 mitogen-activated protein kinase (MAPK) and protein kinase C (PKC), are involved in the contraction produced by either 5-HT or U46619 (an analog of TXA2) in the rat aorta. Both 5-HT and U46619 induced sustained contractions, which were markedly reduced in the absence of extracellular Ca2+. Verapamil (a L-type Ca2+ channel blocker) markedly inhibited the contractile response to 5-HT, while the U46619-induced contraction was only slightly inhibited by verapamil. Both contractile responses to 5-HT and U46619 were significantly inhibited by calphostin C (a PKC inhibitor). On the other hand, both genistein (5 microM, a tyrosine kinase inhibitor) and SB203580 (a p38 MAPK inhibitor) significantly inhibited 5-HT-induced contractions but had little effects on the contractions induced by U46619. These results suggest that the signal transduction mechanisms involved in the contractions mediated via 5-HT and TXA2 receptors are different as follows. Both the tyrosine kinase and p38 MAPK pathways are involved in 5-HT contraction but not in TXA2 contraction, while both contractions are strongly dependent on transplasmalemmal Ca2+ entry. The contractile responses to both 5-HT and TXA2 involve voltage-dependent Ca2+ channels and PKC.     

Microtubule disruption modulates the Rho-kinase pathway in vascular smooth muscle

Microtubules constitute one of the main cytoskeletal components in eukaryotic cells. Recent studies have shown that microtubule disruption induced significant vasoconstriction or enhanced agonist-induced contraction in vascular smooth muscle. However, the underlying mechanisms are not clear. We hypothesize that microtubule disruption may affect contractile signaling in vascular smooth muscle and lead to the enhanced contraction. The present study demonstrates that both colchicine and nocodazole induced a small but sustained contraction (4–6% P ₀) in rat aortic rings. This microtubule disruption-induced contraction was abolished by co-treatment with either HA 1077 or Y-27632, both of which are relatively specific Rho-kinase inhibitors. However, co-treatment with ML-9, an inhibitor of myosin light chain kinase, (MLCK) did not have a significant effect on the colchicine-induced contraction. The enhanced KCl-induced contraction due to treatment with colchicine was also blocked by inhibition of Rho-kinase, but not by inhibition of MLCK. These results indicate that microtubule disruption modulates contractile signaling in vascular smooth muscle, mainly through the Rho-kinase pathway, but not MLCK. Interestingly, the colchicine-enhanced, phenylephrine-induced contraction was not completely blocked by inhibition of Rho-kinase suggesting that other signaling pathways might also be involved.     

血管紧张素Ⅱ对大鼠心率和心率变异的影响

目的研究血管紧张Ⅱ(AngⅡ)对大鼠心率以及变异(HRV)的影响及其机制。方法大鼠股静脉注射5%葡萄糖然后输注AngⅡ作为实验组,股静脉注射AT1受体(Angiotensin Ⅱ receptorⅠ)阻断剂氯沙坦(Losartan,LOS)然后输注AngⅡ作为对照组。对各组大鼠进行心电图(ECG)和BP(血压)数据的采集,对各组大鼠HRV的频域指标进行分析。结果与实验组相比,对照组频域指标低频(LF)和LF/HF明显降低而高频(HF)明显升高(P<0.05),而心率(HR)没有显著变化(P>0.05)。结论 AngⅡ对大鼠的HRV作用是通过AT1受体实现的。     

Inhibition of Contraction and Myosin Light Chain Phosphorylation in Guinea-Pig Smooth Muscle by p21-Activated Kinase 1

The p21-activated protein kinases (PAKs) have been implicated in cytoskeletal rearrangements and modulation of non-muscle contractility. Little, however, is known about the role of the PAK family members in smooth muscle contraction. Therefore, we investigated the effect of the predominant isoform in vascular smooth muscle cells, PAK1, on contraction and phosphorylation of the regulatory light chains of myosin (r-MLC) in Triton-skinned guinea-pig smooth muscle. We also investigated which of the three putative substrates at the contractile apparatus - MLCK, caldesmon or r-MLC - is phosphorylated by PAK1 in smooth muscle tissue. Incubation of Triton-skinned carotid artery and taenia coli from guinea-pig with an active mutant of PAK1 in relaxing solution for 30–60 min resulted in inhibition of submaximal force by about 50 %. The mechanism of inhibition of force was studied in the Triton-skinned taenia coli. In this preparation, inhibition of force was associated with a respective inhibition of r-MLC phosphorylation. In the presence of the myosin phosphatase inhibitor, microcystin-LR (10 μ m ), the rate of contraction and r-MLC phosphorylation elicited at pCa 6.79 were both decreased. Because under these conditions the rate of r-MLC phosphorylation is solely dependent on MLCK activity, this result suggests that the inhibitory effect of PAK1 on steady-state force and r-MLC phosphorylation is due to inhibition of MLCK. In line with this, we found that MLCK was significantly phosphorylated by PAK1 while there was very little ³²P incorporation into caldesmon. PAK1 phosphorylated isolated r-MLC but not those in the skinned fibres or in purified smooth muscle myosin II. In conclusion, these results suggest that PAK1 attenuates contraction of skinned smooth muscle by phosphorylating and inhibiting MLCK.     

CX3CL1/CX3CR1 Axis Contributes to Angiotensin II-Induced Vascular Smooth Muscle Cell Proliferation and Inflammatory Cytokine Production

Angiotensin II (Ang II) dysregulation has been determined in many diseases. The CX3CL1/CX3CR1 axis, which has a key role in cardiovascular diseases, is involved in the proliferation and inflammatory cytokine production of vascular smooth muscle cells (VSMCs). In this study, we aim to explore whether Ang II has a role in the expression of CX3CL1/CX3CR1, thus contributing to the proliferation and pro-inflammatory status of VSMCs. Cultured mouse aortic VSMCs were stimulated with 100 nmol/L of Ang II, and the expression of CX3CR1 was assessed by western blot. The results demonstrated that Ang II significantly up-regulated CX3CR1 expression in VSMCs and induced the production of reactive oxygen species (ROS) and the phosphorylation of p38 MAPK. Inhibitors of NADPH oxidase, ROS, and AT1 receptor significantly reduced Ang II-induced CX3CR1 expression. Targeted disruption of CX3CR1 by transfection with siRNA significantly attenuated Ang II-induced VSMC proliferation as well as down-regulated the expression of proliferating cell nuclear antigen (PCNA). Furthermore, CX3CR1-siRNA suppressed the effect of Ang II on stimulating Akt phosphorylation. Besides, the use of CX3CR1-siRNA decreased inflammatory cytokine production induced by Ang II treatment. Our results indicate that Ang II up-regulates CX3CR1 expression in VSMCs via NADPH oxidase/ROS/p38 MAPK pathway and that CX3CL1/CX3CR1 axis contributes to the proliferative and pro-inflammatory effects of Ang II in VSMCs.     

血管紧张素Ⅱ对血管平滑肌血小板源生长因子

目的:观察血管紧张素Ⅱ对血管平滑肌血小板源生长因子(PDGF)受体β亚单位的调节,探讨两条信号转导途径的交互作用在血管平滑肌细胞(VSMC)增殖中的意义。方法:制备两肾一夹肾性高血压大鼠模型,免疫印迹法检测主动脉组织PDGF受体β亚单位的含量。培养大鼠主动脉VSMC,观察血管紧张素Ⅱ(AngⅡ)对PDGF受体β亚单位的影响。结果:两肾一夹大鼠术后8周动脉血压明显增高,同时主动脉PDGF受体β亚单位的表达高于对照组126.6%(P＜0.05)。AngⅡ刺激培养的VSMC可导致PDGF受体β亚单位上调192.74%(P＜0.01),该效应可被Ⅰ型AngⅡ受体(AT₁)的拮抗剂losartan和磷脂酶C(phospholipasec,PLC)的抑制剂U73122完全阻断(P＜0.01),但仅被丝裂原活化蛋白激酶激酶抑制剂PD98059部分阻断(P＜0.01)。结论:AngⅡ可以通过AT₁及下游的信号分子PLC上调PDGF受体β亚单位的表达,而细胞外信号调节激酶可能参与AngⅡ的胞内信号转导。     

RhoA调节失血性休克大鼠血管反应性的机制

目的： 探讨RhoA调节失血性休克大鼠血管反应性的机制。方法: 采用SD大鼠复制休克模型,取离体血管环,观察Rho激酶、肌球蛋白轻链磷酸酶（MLCP）、肌球蛋白轻链磷酸激酶（MLCK）对RhoA增加血管反应性的作用;同时取原代血管平滑肌细胞（VSMCs）,观察RhoA对缺氧后VSMC Rho激酶、MLCP和MLCK活性的调节作用以及对肌球蛋白轻链（MLC20）磷酸化水平的影响。结果: 失血性休克后大鼠肠系膜上动脉（SMA）对NE收缩反应性明显降低,RhoA的激动剂U-46619可明显升高休克后血管反应性,RhoA特异性抑制剂C3酶可拮抗U-46619所引起的血管收缩反应性的升高。Rho激酶抑制剂Y-27632可降低由U-46619所引起的血管反应性的升高,MLCP的抑制剂Calyculin可进一步增加由U-46619所引起的血管反应性的升高,而MLCK抑制剂对U-46619的作用影响不明显。缺氧后MLCK、Rho激酶活性以及MLC20磷酸化水平明显降低,MLCP活性明显升高,RhoA激动剂U-46619可明显升高缺氧后VSMC的MLC20磷酸化水平、Rho激酶活性和降低MLCP的活性,且U-46619的这一作用可被RhoA抑制剂C3酶所拮抗,调节RhoA的活性对MLCK活性无明显调节作用。结论: RhoA可通过Rho激酶调节MLCP活性和 MLC20磷酸化水平调节休克后血管反应性。