PKC/NADPH氧化应激途径对大鼠心脏微血管内皮细胞eNOS脱偶联的影响

目的 观察体外原代培养大鼠心脏微血管内皮细胞内PKC/NADPH氧化应激途径在eNOS脱偶联中的作用.方法 用牛血清白蛋白糖基化终末产物(BSA-AGEs)(100 mg/L)与LY33531(PKC抑制剂)和DPI(NADPH抑制剂)分别作用大鼠心脏微血管内皮细胞(24 h),HPLC法检测BH4,试剂盒检测NO和O2-生成,免疫组化检测eNOS蛋白表达,Western blot法检测P47phox蛋白表达.结果 随着LY33531和DPI浓度(5、10和20 μmol/L)的增加,eNOS脱偶联状态减轻:NO生成逐渐增加(90.7 ±0.3～122.6 ±0.3,160.6 ±0.6,P＜0.05),而O2-生成逐渐减少(P＜0.05),eNOS表达逐渐减少(126.1 ±3.5 ～ 112.6±1.7,114.4 ±1.8,P＜0.05),而BH4含量逐渐增加(P＜0.05).同时,ROS表达和P47phox表达减少(P＜0.05).结论 NADPH氧化应激途径可能参与AGEs诱导的心脏微血管内皮细胞eNOS脱偶联的发生.而AGEs诱导的心脏微血管内皮细胞内NADPH氧化应激的发生是依赖PKC激活的.     

低氧对人脐静脉内皮细胞一氧化氮和内皮素-1的生成及诱导型一氧化氮合酶mRNA表达的影响

目的：通过观察低氧对人脐静脉内皮细胞(HUVECs)分泌一氧化氮(NO）、内皮素-1(ET-1)以及诱导型一氧化氮合酶(iNOS)mRNA 表达的影响，探讨低氧性肺动脉高压(HPH)形成的机制。 方法： 在离体培养人脐静脉内皮细胞基础上，采用硝酸还原酶和放射免疫分析方法检测了低氧（3％O2）培养6 h、12 h和24 h人脐静脉内皮细胞分泌NO和ET-1的变化，同时运用半定量RT-PCR对iNOS mRNA表达情况进行分析。 结果： 低氧组各时点培养液中NO2-/NO3-和ET-1水平显著高于常氧组(P<0.01)，同时观察到iNOS基因mRNA的表达也相应增高(P<0.01)。 结论： 低氧能刺激人脐静脉内皮细胞生成释放NO和ET-1, NO生成增多与低氧正调iNOS基因mRNA的表达有关。     

抗氧化剂和NFκB对大鼠肺微血管内皮细胞iNOS表达的影响

目的 :探讨NFκB在大鼠肺微血管内皮细胞iNOS基因诱导表达中的作用及抗氧化剂对内皮细胞iNOS诱导表达的影响及其机制。方法 :Griess法测定细胞培养上清液NO-2 水平以反映NO的生成 ,Northern印迹分析iNOSmRNA水平 ,EMSA法测定细胞核内NFκB的结合活性。结果 :抗氧化剂可阻断内皮细胞培养体系LPS和TNFα诱导的NO生成及iNOSmRNA的表达 ;LPS和TNFα可诱导大鼠肺微血管内皮细胞NFκB的激活并可被抗氧化剂阻断。结论 :LPS和TNFα诱导的内皮细胞iNOS基因表达依赖于NFκB的激活 ;抗氧化剂可通过抑制NFκB的活化而阻断iNOS基因的诱导表达     

葛根素对糖尿病大鼠白内障过程中晶状体诱导型一氧化氮合酶的影响

目的: 观察大鼠糖尿病性白内障(DC)晶状体诱导型一氧化氮合酶(iNOS)基因表达变化及葛根素对DC的治疗作用。方法: 经腹腔注射链脲佐菌素(STZ)复制大鼠DC模型。实验分为STZ组(STZ,45 mg/kg bw,ip)、葛根素组(STZ+葛根素,140 mg/kg bw ip)和对照组(等量生理盐水,ip),分别于实验第20、40、60 d摘取大鼠晶状体,用逆转录聚合酶链反应(RT-PCR)、蛋白印迹(Western blot)和生化方法检测晶状体iNOS mRNA和蛋白表达及一氧化氮(NO)含量、一氧化氮合酶(NOS)活性变化,观察晶状体损伤的宏观和微观病理变化。 结果:对照组大鼠晶状体透明,iNOS mRNA未见明显表达,蛋白呈微弱表达,NOS活性较低,NO含量较少。在DC形成过程中,晶状体出现混浊、晶状体上皮细胞(LEC)有明显病变,并随病程延长而加重;晶状体iNOS mRNA和蛋白表达明显上调,NOS活性增强、NO生成增加,并呈现时间依赖性。用药40-60 d时葛根素组前述晶状体病理变化轻于STZ组,iNOS mRNA和蛋白表达明显低于STZ组,NOS活性及NO 生成低于STZ组。结论: 在大鼠DC形成过程中晶状体iNOS 基因表达上调、NO含量增加;葛根素可减轻晶状体损伤,机制可能与抑制iNOS 基因表达、减少NO生成有关。     

创伤弧菌溶细胞素融合蛋白对小鼠单核巨噬细胞产NO及其合酶的影响

目的 研究创伤弧菌溶细胞素融合蛋白(rVvhA)对小鼠单核-巨噬细胞(J774A.1)产生一氧化氮(NO)和诱导型一氧化氮合酶(iNOS)表达的影响.方法 应用MTT法检测rVvhA对J774A.1增殖的抑制作用;Griess法检测NO含量;RT-PCR和免疫荧光法检测iNOS mRNA和蛋白表达水平.结果 0.8 HU/ml及以上浓度rVvhA可显著抑制J774A.1的增殖;在IFN-γ的辅助作用下,0.4 HU/ml的rVvhA即可诱导J774A.1产生大量NO,显著增加细胞内活性以及iNOS mRNA和蛋白表达水平.结论 rVvhA可诱导巨噬细胞产生NO和iNOS表达,在创伤弧菌的致病机制中具有重要意义.     

高压氧抑制一氧化氮生成改善缺血性脑细胞凋亡

目的探讨高压氧对脑缺血再灌流脑皮层一氧化氮(NO)生成的影响及其对脑细胞的保护作用。方法采用沙土鼠双侧颈总动脉夹闭30min再灌流模型。用电化学及免疫细胞化学方法检测脑皮层一氧化氮生成、一氧化氮合酶(NOS)表达及神经细胞凋亡。结果缺血再灌流期沙土鼠脑皮层中NO的含量显著增加，3型NOS均有表达，缺血再灌流第2d，iNOS的表达最为明显，同时NO的生成达到高峰。缺血再灌流第1、2、3d，沙土鼠脑皮层均可见凋亡细胞，以第2、3d更为明显。高压氧暴露能明显抑制iNOS表达，减少NO生成，减轻神经细胞凋亡。结论高压氧能抑制沙土鼠脑缺血再灌流期脑皮层NO生成，减轻神经细胞凋亡，从而起到脑保护作用。     

血管生成素1,2通过诱导型一氧化氮合酶调节失血性休克大鼠血管低反应性

目的:观察诱导型一氧化氮合酶(iNOS)在血管生成素-1(Ang-1)、血管生成素-2(Ang-2)调节失血性休克大鼠血管反应性双相变化中的作用。方法:采用WesternBlotting观察iNOS蛋白表达,同时采用离体微血管环张力测定技术检测血管反应性,以及细胞一氧化氮(NO)含量。结果:iNOS表达在失血性休克后逐渐增高;iNOS抑制剂可显著恢复缺氧4h的血管低反应性,抑制Ang-2进一步降低缺氧4h血管反应性的作用,去甲肾上腺素(NE)的最大收缩力(Emax)分别由5.875mN增高至8.937mN和由3.444mN增高至7.492mN(P<0.01);Ang-1,Tie-2、p38MAPK和Erk抑制剂可抑制缺氧4h的iNOS表达和增加NO生成(P<0.01)。结论:失血性休克晚期,Ang-1和Ang-2可通过p38MAPK和Erk调节iNOS蛋白表达,增加NO生成来调节血管低反应性。     

p38 MAPK-iNOS-NO通路介导化学性缺氧对PC12细胞的损伤作用

目的:探讨诱导型一氧化氮合酶/一氧化氮(iNOS/NO)是否介导了氯化钴(CoCl2)引起的PC12细胞损伤及p38 MAPK对其调节作用。方法:应用化学性低氧模拟剂CoCl2处理PC12细胞建立化学性缺氧损伤模型。应用细胞计数试剂盒-8(CCK-8)比色法检测细胞存活率;Hochest33258核染色法观察细胞凋亡的形态学改变;Western blotting法检测iNOS蛋白的表达水平;Griess试剂盒检测细胞培养基中亚硝酸盐(NO的代谢物)的浓度。结果:应用600μmol/L CoCl2处理PC12细胞24 h可使iNOS表达明显增多;应用600μmol/L CoCl2处理PC12细胞24 h和48 h可使细胞培养基里NO增多;在CoCl2损伤PC12细胞前60 min应用iNOS抑制剂L-canavanine(10μmol/L)预处理能保护PC12细胞对抗600μmol/L CoCl2引起的损伤,使细胞存活率升高,凋亡细胞数目减少;SB203580(p38 MAPK选择性抑制剂)预处理60 min可下调CoCl2引起的iNOS高表达。结论:p38 MAPK-iNOS-NO通路介导CoCl2引起PC12细胞的损伤作用。     

纳米银联合放疗对大鼠胶质瘤内iNOS表达和NO水平的影响

目的:研究局部使用纳米银联合放疗对大鼠胶质瘤内诱导型一氧化氮合酶(iNOS)表达和一氧化氮(NO)含量的影响。方法:将C6细胞接种于大鼠右侧尾状核,建模后第8 d,将荷瘤鼠随机分成放疗对照组和纳米银联合放疗组,分别立体定向注入等体积的去离子水及20μg的纳米银,并行单次电离辐射。观察放疗后瘤组织形态学变化,免疫组织化学法检测iNOS蛋白表达,硝酸还原酶法测定NO含量。结果:瘤组织放疗后细胞排列紊乱、密度减少。放疗后6 h胶质瘤内iNOS即有表达,随着时间的延长,iNOS表达进一步增强。放疗后6 h和24h,纳米银联合放疗组iNOS活性均较放疗对照组增高,差异有统计学意义(P<0.01或P<0.001);NO含量的变化与iNOS变化规律基本一致。结论:纳米银联合放疗能够增强iNOS表达,促进NO生成,瘤组织iNOS表达和NO含量改变可能在纳米银联合放疗杀伤胶质瘤细胞的过程中发挥一定的作用。     

原发性高血压患者血清NO、NOS及其亚型水平的分析

目的:测定原发性高血压患者外周血中血清一氧化氮(NO)、一氧化氮合酶(NOS)及其亚型水平,探讨NO/NOS系统参与血压调节的可能机制.方法:原发性高血压患者135例,正常对照组35例.采用化学法检测所有病例外周血的一氧化氮(NO)、总NOS、诱导型一氧化氮合酶(iNOS)和结构型一氧化氮合酶(cNOS)水平并作统计学分析.结果:高血压组NO、NOS、iNOS和cNOS水平均低于正常对照组,且差异具有显著性意义(分别为:P＜0.05,P＜0.01,P＜0.01,P＜0.01);iNOS/cNOS比值与正常对照组相比无显著差异(P＞0.05);对照组和高血压组的NOS浓度与iNOS和cNOS浓度均呈显著正相关;高血压组的cNOS水平与iNOS水平呈显著负相关.结论:高血压患者NO、NOS及其亚型浓度值可以作为临床评估高血压的参考指标;iNOS在正常人体内有表达;在高血压情况下,机体有通过增加iNOS的表达来弥补cNOS水平的病理性降低、调控NOS总体水平从而调节和平衡血压的趋势.     

Advanced glycation end products accelerate ischemia/reperfusion injury through receptor of advanced end product/nitrative thioredoxin inactivation in cardiac microvascular endothelial cells

The advanced glycation end products (AGEs) are associated with increased cardiac endothelial injury. However, no causative link has been established between increased AGEs and enhanced endothelial injury after ischemia/reperfusion. More importantly, the molecular mechanisms by which AGEs may increase endothelial injury remain unknown. Adult rat cardiac microvascular endothelial cells (CMECs) were isolated and incubated with AGE-modified bovine serum albumin (BSA) or BSA. After AGE-BSA or BSA preculture, CMECs were subjected to simulated ischemia (SI)/reperfusion (R). AGE-BSA increased SI/R injury as evidenced by enhanced lactate dehydrogenase release and caspase-3 activity. Moreover, AGE-BSA significantly increased SI/R-induced oxidative/nitrative stress in CMECs (as measured by increased inducible nitric oxide synthase expression, total nitric oxide production, superoxide generation, and peroxynitrite formation) and increased SI/R-induced nitrative inactivation of thioredoxin-1 (Trx-1), an essential cytoprotective molecule. Supplementation of EUK134 (peroxynitrite decomposition catalyst), human Trx-1, or soluble receptor of advanced end product (sRAGE) (a RAGE decoy) in AGE-BSA precultured cells attenuated SI/R-induced oxidative/nitrative stress, reduced SI/R-induced Trx-1 nitration, preserved Trx-1 activity, and reduced SI/R injury. Our results demonstrated that AGEs may increase SI/R-induced endothelial injury by increasing oxidative/nitrative injury and subsequent nitrative inactivation of Trx-1. Interventions blocking RAGE signaling or restoring Trx activity may be novel therapies to mitigate endothelial ischemia/reperfusion injury in the diabetic population.     

罗格列酮对改善糖尿病大鼠心肌微血管内皮细胞功能的影响

目的探讨罗格列酮对糖尿病大鼠心肌微血管内皮细胞功能的影响。方法腹腔注射小剂量链脲佐菌素结合高能量饲料制备2型糖尿病大鼠模型，随机分为未治疗组与治疗组：罗格列酮4mg／（kg·d）。16周后定量测定血管内皮损伤标志物：可溶性血管内皮细胞蛋白C受体（sEPCR）、可溶性血栓调节蛋白（sTM）、血管性血友病因子（VWF）和一氧化氮（NO）的血浆浓度。分光光度法及免疫组化法分别测定心肌组织内NO浓度、NO合酶（NOS）的活性及内皮型NO合酶（cNOS）在微血管内皮细胞的表达。结果罗格列酮治疗组血糖及血浆中sEPCR、sTM、vWF显著低于未治疗组，但高于非糖尿病对照组。与未治疗组比较，罗格列酮治疗组心肌组织中NO、结构型NOS（cNOS）含量增高，eNOS阳性反应产物量增多，而诱导型NOS（iNOS）含量降低。结论罗格列酮可以降低糖尿病大鼠血糖，减轻内皮细胞损伤与改善心肌微血管内皮细胞功能，有助于减少糖尿病时心肌微血管病的发生与发展。     

糖尿病大鼠血管糖基化终产物含量与其受体的ICAM—1表达的关系

探讨糖尿病大鼠血管组织糖基化终产物（AGEs)含量与其受体（RAGE）和细胞间粘附因子－1（ICAM－1）表达的关系。复制糖尿病大鼠模型,采用荧光法、RT－PCR及原位杂交方法检测主动脉及心肌组织的AGEs含量以及RAGE和ICAM－1基因的表达。发现糖尿病大鼠主动脉和心肌组织AGEs含量升高（P＜0．01）;RAGE和ICAM－1基因表达增强（P＜0．05－0．05）;AGEs含量与RAGE及ICAM－1呈明显正相关（P＜0．01）;氨基胍治疗可缓解上述指标的变化。提示 AGEs可诱导RAGE和ICAM－1的表达。推测AGEs-RAGE相互作用是引起糖尿病血管内皮细胞功能紊乱和损伤的关键环节。     

Regulation of iNOS-Derived ROS Generation by HSP90 and Cav-1 in Porcine Reproductive and Respiratory Syndrome Virus-Infected Swine Lung Injury

In the lungs, endothelial nitric oxide synthase (eNOS) is usually expressed in endothelial cells and inducible nitric oxide synthase (iNOS) is mainly expressed in alveolar macrophages and epithelial cells. Both eNOS and iNOS are involved in lung inflammation. While they play several roles in lung inflammation formation and resolution, their expression and activity are also regulated by inflammatory factors. Their expression relationship in virus infection-induced lung injury is not well addressed. In this report, we analyzed expression of both eNOS and iNOS, the production of nitric oxide (NO) and reactive oxygen species (ROS), and expression of their associated regulatory proteins, heat shock protein 90 (HSP90) and caveolin-1 (Cav-1), in a swine lung injury model induced by porcine reproductive and respiratory syndrome virus (PRRSV) infection. The combination of upregulation of iNOS and downregulation of eNOS was observed in both natural and experimental PRRSV-infected lungs, while the combination is much enhanced in natural infected lungs. While NO production is much reduced in both infections, ROS was enhanced only in natural infected lungs. Moreover, HSP90 is increased in both natural and experimental infection and less Cav-1 expressed was observed only in the natural PRRSV-infected lungs. Therefore, the increased ROS generation is likely due to the increased iNOS and its unbalanced regulation by HSP90 and Cav-1, and it also likely causes higher endothelial dysfunction in clinical PRRSV-infected lungs.     

糖基化终产物和高糖对小牛主动脉血管细胞的损伤作用

目的研究糖基化终产物（AGEs）和高浓度葡萄糖对血管细胞的损伤及对其糖基化终产物受体（RAGE）表达的影响。方法分别用10g/L糖基化终产物、10mol／L葡萄糖和两者的混合作用于牛主动脉血管细胞，利用生化方法测定细胞乳酸脱氢酶（IDH）、还原型谷胱甘肽（GSH）和NO2^-／NO3^-的含量，用MTT法测定细胞的活性。用CELL-ELISA和RT-PCR检测细胞RAGE的表达。结果与正常组（C）相比，高糖组（G）、AGEs组（A）和联合损伤组（G＋A）对主动脉内皮细胞的生长有明显的抑制作用（P〈0．01）和对平滑肌细胞的生长有明显的促进作用，主动脉血管细胞LDH的泄漏量明显增高，GSH和NO2^-／NO3^-的含量明显减少（P〈0．01）；且在的作用最强。同时，联合损伤组血管细胞的RAGE表达水平明显高于AGEs组和高糖组。结论AGEs比高浓度葡萄糖更具损伤血管细胞的作用，且AGEs与高糖联合作用对细胞的损伤最为明显，这种联合损伤的过程也是通过RAGE介导的。联合损伤组     

普罗布考和辛伐他汀对高级糖基化终末产物诱导的大鼠肾脏微血管内皮细胞的ROS含量和HO-1表达影响

目的:探讨普罗布考和辛伐他汀对高级糖基化终末产物(AGEs)诱导的大鼠肾脏微血管内皮细胞(RMECs)活性氧(ROS)含量和血红素氧合酶-1(HO-1)表达的影响。方法:体外分离和培养RMECs,将其分为对照组、AGEs损伤组、普罗布考组和辛伐他汀组;2',7'二氯荧光黄双乙酸盐(DCFH-DA)荧光染色检测各组细胞中ROS含量;逆转录聚合酶链反应法及Westernblotting检测各组细胞血红素氧合酶-1(HO-1)mRNA水平和蛋白表达。结果:(1)AGEs能上调RMECs中ROS生成和HO-1表达(P0.05或P0.01)。(2)普罗布考能上调RMECs中HO-1表达,能下调AGEs诱导RMECs中ROS生成和HO-1表达(P0.05或P0.01)。(3)辛伐他汀能下调AGEs诱导细胞ROS含量增加,但对RMECs中HO-1表达无明显影响(P0.05)。结论:普罗布考对AGEs诱导下RMECs保护作用机制可能与其能下调内皮细胞HO-1表达有关;而同样具有抗氧化保护肾脏作用的辛伐他汀对AGEs诱导的RMECs的HO-1表达的影响不大。     

L-arginine availability regulates inducible nitric oxide synthase-dependent host defense against Helicobacter pylori

Helicobacter pylori infection of the stomach causes an active immune response that includes stimulation of inducible nitric oxide (NO) synthase (iNOS) expression. Although NO can kill H. pylori, the bacterium persists indefinitely, suggesting that NO production is inadequate. We determined if the NO derived from iNOS in macrophages was dependent on the availability of its substrate, L-arginine (L-Arg). Production of NO by H. pylori-stimulated RAW 264.7 cells was dependent on the L-Arg concentration in the culture medium, and the 50% effective dose for L-Arg was 220 microM, which is above reported plasma L-Arg levels. While iNOS mRNA induction was L-Arg independent, iNOS protein increased in an L-Arg-dependent manner that did not involve changes in iNOS protein degradation. L-lysine, an inhibitor of L-Arg uptake, attenuated H. pylori-stimulated iNOS protein expression, translation, NO levels, and killing of H. pylori. While L-Arg starvation suppressed global protein translation, at concentrations of L-Arg at which iNOS protein was only minimally expressed in response to H. pylori, global translation was fully restored and eukaryotic translation initiation factor alpha was dephosphorylated. H. pylori lacking the gene rocF, which codes for a bacterial arginase, induced higher levels of NO production by increasing iNOS protein levels. When murine gastric macrophages were activated with H. pylori, supraphysiologic levels of L-Arg were required to permit iNOS protein expression and NO production. These findings indicate that L-Arg is rate limiting for iNOS translation and suggest that the levels of L-Arg that occur in vivo do not permit sufficient NO generation by the host to kill H. pylori.     

内皮细胞中一种新的可溶型黏附分子sCD226的表达调变规律

目的：探讨人内皮细胞中一种新的可溶型黏附分子sCD226的表达调变规律。方法：用ELISA方法，检测不同浓度的LPS刺激人脐静脉内皮细胞后不同时间点培养上清中sCD226含量的变化；用Greiss法检测上述细胞培养上清中N0含量的变化，并分析两者的线性相关性。加入抗TNF-α中和抗体和iNOS抑制剂后，观察其对LPS诱导sCD226生成的影响。结果：①随着LPS刺激剂量的增加和刺激时间的延长，HUVEC培养上清中sCD226的含量明显增加，100mg／L LPSS刺激3d后sCD226的含量为188．5μg／L。②LPS刺激剂量为100mg／L时，HUVEC培养上清中sCD226和N0的含量呈显著的正相关。③抗TNF—α中和抗体和iNOS抑制剂可显著抑制LPS活化的HUVEC产生sCD226。结论：LPS可诱导HUVEC产生sCD226分子，且sCD226的生成与N0和TNF-α的产生密切相关。