罗格列酮减轻2型糖尿病大鼠血管内皮功能受损

目的观察2型糖尿病大鼠血清内皮素(ET)和一氧化氮(NO)水平、主动脉病理变化、在主动脉的内皮型一氧化氮合酶(e NOS)蛋白和mRNA表达及罗格列酮的干预作用。方法将大鼠随机分为对照组、高脂组、糖尿病组和罗格列酮组,每组20只。制备2型糖尿病大鼠模型后,罗格列酮治疗组4 mg/kg·d灌胃给药,于治疗6周和12周时检测血糖、ET、NO及光镜下主动脉的病理变化;用Western blot和real-time PCR检测主动脉的e NOS蛋白和mRNA表达。结果 1)与对照组比较,高脂组、糖尿病组及罗格列酮治疗组ET升高,NO降低(P0.01)。12周时糖尿病组较高脂组和罗格列酮治疗组ET升高,NO降低(P0.05)。糖尿病组NO水平在12周时比6周时明显下降(P0.05)。2)12周时高脂组、糖尿病组和罗格列酮组大鼠主动脉出现不同程度病理改变。3)6周和12周时,与对照组比较,高脂组、糖尿病组和罗格列酮组主动脉e NOS的蛋白和mRNA表达下调(P0.01);糖尿病组较罗格列酮组主动脉e NOS的蛋白表达下调(P0.01)。结论罗格列酮可以缓解糖尿病组大鼠血管内皮功能受损。     

罗格列酮通过激活PPARγ改善肺动脉高压大鼠肺动脉内皮依赖性舒张功能

 目的：探索过氧化物酶体增殖物激活受体γ（PPARγ）激动剂罗格列酮对肺动脉高压大鼠模型肺动脉血管内皮功能的影响。方法：（1）SD大鼠40只,分为正常对照组、模型组、罗格列酮组和罗格列酮+GW9662（PPARγ拮抗剂）干预组,每组10只,以野百合碱（60 mg/kg）一次性皮下注射复制肺动脉高压大鼠模型,再灌胃给予罗格列酮（2.0 mg·kg-1·d-1）或罗格列酮 + GW 9662（0.3 mg·kg-1·d-1）干预。4周后,取血浆测一氧化氮（NO）及内皮素-1（ET-1）的水平,分离肺动脉二级分支,以微血管张力测定仪测定肺动脉血管功能变化情况。（2）体外培养人肺动脉内皮细胞株（HPAECs）,探讨罗格列酮对HPAECs　NO生成的影响。结果：罗格列酮可显著改善肺动脉高压大鼠血管内皮依赖性舒张功能,但不能显著改善非内皮依赖性舒张功能;罗格列酮干预可降低血浆ET-1水平,升高NO水平;但罗格列酮的以上作用在同时给予PPARγ拮抗剂GW9662时显著被减弱。体外实验证实,罗格列酮可显著增加HPAECsf的NO生成,但该作用同样可被GW9662所阻断。结论：罗格列酮通过激活PPARγ改善肺动脉高压大鼠的血管内皮依赖性舒张功能可能是其治疗肺动脉高压的基础。     

罗格列酮对大鼠急性心肌梗死再灌注后无复流的影响

目的 探讨罗格列酮对急性心肌梗死(AMI)再灌注后无复流及内皮型一氧化氮合酶（eNOS）表达的影响。方法 结扎大鼠左冠状动脉前降支3 h后松解2 h建立AMI再灌注后无复流动物模型,将60只大鼠随机分为对照组、假手术组、罗格列酮组、罗格列酮+L-NNA（NOS抑制剂）组、L-NNA组;以伊文思蓝-硫磺素染色法检测大鼠心肌组织无复流范围;Western blot检测丝氨酸1177磷酸化内皮型一氧化氮合酶(p-eNOS Ser1177)蛋白表达,RT-PCR检测eNOS mRNA的表达。结果 （1）与对照组相比,罗格列酮组大鼠心肌组织无复流范围明显减小（P<0.05）,而L-NNA+罗格列酮组无复流范围无显著差异;（2）罗格列酮组eNOS mRNA表达较对照组无显著差别,而p-eNOS Ser1177蛋白表达显著增强(P<0.05);结论 罗格列酮显著减小AMI再灌注后无复流范围,其机制与其促进再灌注后eNOS磷酸化,增加NO释放有关。     

血管内皮损伤标志物在2型糖尿病患者中的变化

目的:探讨2型糖尿病(DM)患者血管内皮损伤标志物的变化。方法:分别测定89例2型DM患者和76例正常对照者血浆可溶性血管内皮细胞蛋白C受体(sEPCR),血管性血友病因子(v WF)和可溶性血栓调节蛋白(sTM),并测定DM患者24h尿白蛋白排泄(UAE),根据尿UAE水平和病程分组进行比较分析。结果:2型DM患者血浆sEPCR、v WF及sTM水平高于正常对照组(P<0.05),并且与其尿UAE水平和病程呈显著正相关。结论:血浆sEPCR、v WF及sTM水平可作为观察2型DM并发血管病变以及严重程度的指标。     

肢体缺血预适应的小肠保护作用及与一氧化氮/内皮素-1的关系

目的：观察一氧化氮/内皮素-1(NO/ET-1)失衡与肢体缺血再灌注(I/R)后小肠损伤的关系，以及缺血预适应(IPC)对NO/ET-1系统的调节作用。 方法： 雄性Wistar大鼠18只，随机分为对照（control）组，缺血再灌注（IR）组和缺血预适应（IPC+IR）组，每组6只，分别测定血浆和小肠组织二氨氧化酶(DAO)、一氧化氮(NO)、内皮素-1(ET-1)、NO/ET-1比值的含量变化及小肠组织的髓过氧化物酶(MPO)、DNA双链百分率(ratio of DNA chain %)、总一氧化氮合酶（tNOS）、诱导型一氧化氮合酶（iNOS）、结构型一氧化氮合酶（cNOS）的水平；免疫组化法检测小肠组织的诱导型一氧化氮合酶（iNOS）、内皮型一氧化氮合酶（eNOS）的表达。 结果： IR组血浆和小肠组织NO、ET-1，血浆DAO及组织MPO均明显高于对照组，而 NO/ET-1的比值，组织DAO及DNA双链百分率明显少于对照组；小肠粘膜iNOS的表达及总NOS活性高于对照组，cNOS（主要为eNOS）的表达少于对照组。IPC+IR组血浆和小肠组织NO、ET-1，血浆DAO及组织MPO均明显少于IR组，而 NO/ET-1的比值，组织DAO及DNA双链百分率却明显高于IR组；小肠粘膜iNOS的表达及总NOS活性少于IR组，cNOS（主要为eNOS）的表达高于IR组。 结论： 肢体I/R后小肠损伤与NO/ET-1失衡有关，IPC对肢体IR继发的小肠粘膜损伤的拮抗作用可能通过对NO/ET-1系统的调节作用而介导，此时内皮源的NO产生增加，非内皮源的NO产生减少。     

桑银降糖胶囊对实验性糖尿病大鼠微血管的影响

目的观察桑银降糖胶囊对实验性糖尿病大鼠治疗后心脑微血管病的变化,探讨桑银降糖胶囊对实验性糖尿病大鼠血管调节因子的影响。方法用微量血糖测试仪检测各组糖尿病大鼠血糖和糖耐量,用化学比色法测定血清中NO的含量,应用放免法测定血浆内皮素（ET-1）含量。电镜观察心脑超微结构。结果与模型组比较,桑银降糖胶囊对STZ大鼠均有显著的降血糖作用（P〈0．01）;2h血糖曲线下面积为38．88±8．59（P〈0．01）。大剂量组ET-1为（149．60±16．83）pg／ml（P〈0．01）,NO为（61．20±11．36）μmol／L（P〈0．01）。结论桑银降糖胶囊可提高糖尿病大鼠血清NO含量,下调血浆ET水平,有效抑制由于高血糖等因素引起血管内皮细胞损伤。对糖尿病内皮细胞损伤及微血管病变具有一定的保护作用。     

慢性低氧过程中肺血管内皮细胞损伤和一氧化氮合酶变化

目的：观察慢性低氧时肺血管内皮细胞及肺内一氧化氮合酶（NOS）的改变。方法：利用常压低氧舱复制大鼠慢性低氧模型，使用电镜技术观察肺血管内皮细胞的改变，采用还原型辅酶Ⅱ硫辛酸脱氢酶（ND）细胞化学染色及NOS免疫组化染色观察NOS的改变。结果：肺血管内皮细胞损伤、脱落，肺动脉肌化，随着低氧时间延长，血管内皮细胞NOS蛋白表达递增，但一氧化氮（NO）作用反而减弱。结论：慢性低氧可引起肺血管内皮细胞的损伤、肺内NOS含量和活性增加及内皮源性舒张因子（EDRF）的作用减弱，以致肺动脉发生肌化。     

2型糖尿病并血管病变患者血浆GSH-Px、SOD、NO、NOS含量的变化

目的:探讨2型糖尿病并血管病变患者血浆谷胱甘肽过氧化物酶(GSH-Px)、超氧化物歧化酶(SOD)、一氧化氮(NO)和一氧化氮合酶(NOS)含量变传及临床意义。方法:用化学法测定42例2型糖尿病并血管病变患者血浆GSH-Px、SOD、NO、NOS含量变化,并与50例2型糖尿病不伴血管性病变组和46例健康对照组比较。结果:2型糖尿病并发血管性疾病组血浆GSH-Px、SOD、NO、NOS活性比不伴血管性病变组显著降低(P<0.01),且两组均显著性低于正常对照组(P<0.01)。结论:2型糖尿病患者存在着氧化与抗氧化之间以及内皮细胞分泌NO功能失调,这种失调在2型糖尿病血管并发症发生和发展过程中起重要作用。     

三七总皂苷对异丙肾上腺素所致大鼠心肌肥厚和纤维化的影响

目的：研究三七总皂苷（PNS）对异丙肾上腺素所致大鼠心肌肥厚和纤维化的保护作用。方法： 用异丙肾上腺素（ISO）5 mg·kg^-1·d^-1,sc,连续7 d，建立大鼠心肌肥厚和纤维化模型。造模第2 d开始给大鼠腹腔注射PNS 25和50 mg· kg^-1·d^-1,连续14 d，测定全心重量指数（HW/BW）、左心室重量指数（LVW/BW即LVI）；采用试剂盒用分光光度法检测左心室心肌组织中羟脯氨酸（Hyp）、丙二醛（MDA）、一氧化氮（NO）含量和超氧化物歧化酶（SOD）、谷光苷肽过氧化酶（GSH-Px）、一氧化氮合酶（NOS）活性；用放免分析法检测左心室心肌组织中血管紧张素Ⅱ（AngⅡ）含量。结果： ISO模型组大鼠的HW/BW、LVI、左心室HyP、AngⅡ、MDA含量和诱生型NOS(iNOS)活性显著高于生理盐水对照组，SOD、GSH-Px及结构型NOS(cNOS)活性和NO含量明显比生理盐水对照组低；PNS治疗组左心室心肌组织中NO含量、cNOS 、SOD和GSH-Px活性明显高于ISO模型组；MDA和AngⅡ含量及iNOS活性和心脏重量指数比ISO模型组低。结论： PNS有抗心肌肥厚和纤维化作用，该作用与清除氧自由基及升高NO含量有关。     

一氧化氮在中性粒细胞与激活的内皮细胞间黏附中介导的作用

目的 研究一氧化氮（NO）在大鼠中性粒细胞（PMN）与激活的大鼠肺微血管内皮细胞（PMEC）黏附中的介导作用。方法 分离和培养大鼠中性粒细胞（PMN）和大鼠肺微血管内皮细胞（PMEC），测定PMEC与PMN间黏附率，并测定一氧化氮合酶（NOS）抑制剂L-NMMA孵育的PMEC经烧伤血清或LPS激活后，与PMN间黏附率。结果 L-NMMA能增加烧伤血清或LPS激活后的PMEC与PMN间黏附率。结论 NO介导了PMN与激活的PMEC间黏附。     

Endothelial nitric oxide synthase (eNOS) expression and localization in healthy and diabetic rat hearts

Several studies suggest that nitric oxide (NO) production is reduced in diabetes and that the decrease of NO may be related to the pathogenesis of diabetic endothelial damage. NO synthase (NOS) catalyses the conversion of L-arginine to L-citrulline in the presence of oxygen and NADPH-diaphorase (NADPH-d). In this study, we evaluated the expression of endothelial NOS (eNOS) enzyme and its co-enzyme in diabetic rat hearts. Male Wistar rats (n = 20, 4 mo old) and 20 male Bio Breeding Wistar (BB/W) rats of the same age were used; the Wistar rats represent the control non-diabetic rats while the BB/W rats represent the diabetic group. After the hearts were excised, the NADPH-d co-enzyme was visualized by a histochemical method and the endothelial isoform of NOS was localized by immunohistochemistry. In addition, eNOS gene expression was estimated by rt-PCR, and eNOS protein level was detected by Western blot analysis. The eNOS visualization, which involved immunoprecipitation, and the NADPH-d visualization, which involved histochemical staining, were both diminished in endothelial cells of the vascular wall of diabetic hearts, compared to non-diabetic hearts. The eNOS protein level, evaluated by Western blotting, was evident as an intense band in cardiac homogenates of non-diabetic and diabetic rats. The expression of mRNA for eNOS did not differ significantly between the two groups. These findings indicate that, in this rat heart model, diabetes does not influence the overall eNOS protein level or its mRNA level. However, there a diminution in the deposition of eNOS in cardiac endothelial cells of diabetic rats, versus non-diabetic controls, suggesting a relation between eNOS and the loss of vasodilatory response that is observed in diabetes.     

低糖诱导人脐静脉内皮细胞一氧化氮与活性氧变化的研究

目的观察低浓度葡萄糖对人脐静脉内皮细胞一氧化氮（NO）与活性氧（ROS）变化的影响。方法以体外培养人脐静脉内皮细胞株HUVEC-12为研究对象,将实验分为正常对照组（5.5mmol/L葡萄糖）、低糖组（2.8mmol/L葡萄糖）、无糖组（0mmol/L葡萄糖）。分别用2.8、0mmol/L葡萄糖干预HUVEC-12细胞,经过1、2、4、12h后,硝酸还原酶法测定NO产量,化学比色法测定一氧化氮合成酶（NOS）活性,Dihydroethidium荧光探针法测定细胞内ROS水平。结果与正常对照组相比,低糖组与无糖组NO水平降低（P〈0.01）,NOS活性下降（P〈0.01）,细胞内ROS水平升高（P〈0.01）,均呈剂量依赖关系。同一浓度组内随着时间的延长,内皮细胞NO水平、NOS活性进一步降低（P〈0.01）,ROS水平进一步升高（P〈0.05）,各指标都具有浓度和时间依赖性。结论低糖可导致内皮细胞功能障碍,NO水平降低,NOS活性下降,其机制可能与低糖导致内皮细胞氧化应激损伤有关。     

Elevated glucose attenuates agonist- and flow-stimulated endothelial nitric oxide synthase activity in microvascular retinal endothelial cells.

Impaired vasoactive release of opposing vasodilator and vasoconstrictor mediators due to endothelial dysfunction is integral to the pathogenesis of diabetic retinopathy. The aim of this study was to determine the effect of hyperglycemia on the expression of endothelial nitric oxide synthase (eNOS) and the release of nitric oxide (NO) in bovine microvascular retinal endothelial cells (BRECs) under both static (basal and acetylcholine stimulated) and flow (laminar shear stress [10 dynes/cm2 and pulsatile flow 0.3 to 23 dynes/cm2) conditions using a laminar shear apparatus and an in vitro perfused transcapillary culture system. The activity and expression of eNOS, measured by nitrate levels and immunoblot, respectively, were determined following exposure of BRECs to varying concentrations of glucose and mannitol (0 to 25 mM). Under static conditions the expression of eNOS decreased significantly following exposure to increasing concentrations of glucose when compared to osmotic mannitol controls and was accompanied by a significant dose-dependent decrease in nitrate levels in conditioned medium. The acetylcholine stimulated increase in NO release (2.0 +/- 0.3-fold) was significantly reduced by 55% +/- 5% and 65% +/- 4.5% following exposure to 16 and 25 mM glucose, respectively, when compared to osmotic controls. In parallel studies, glucose significantly inhibited both laminar shear stress and pulsatile flow-induced activity when compared to mannitol. We conclude that hyperglycemia impairs agonist- and flow-dependent release of NO in retinal microvascular endothelial cells and may thus contribute to the vascular endothelial dysfunction and impaired autoregulation of diabetic retinopathy.     

Inducible and endothelial nitric oxide synthase expression during development of transplant arteriosclerosis in rat aortic grafts.

In the vascular system, distinct isoforms of nitric oxide synthase (NOS) generate nitric oxide (NO), which acts as a biological messenger. Its role in the development of transplant arteriosclerosis (TA) is still unclear. To investigate whether NO is involved in TA, we studied the expression of NOS isoforms, inducible NOS (iNOS) and endothelial NOS (eNOS), by immunohistochemistry and in situ hybridization during the first two post-transplantation months and their relation with cold ischemia (1 to 24 hours) and reperfusion injury using an aortic transplantation model in the rat. We found an increased iNOS expression in the intima and adventitia and a decreased expression in the media, whereas eNOS expression was not significantly altered during the development of TA. Co-localization studies suggested that iNOS-positive cells were vascular smooth muscle cells, monocyte-derived macrophages, and endothelial cells. Prolonged ischemic storage time resulted in an increase in eNOS expression in the neointima. In situ hybridization showed iNOS mRNA expression by vascular cells in the neointima and media. NO produced by iNOS and eNOS may be involved, at least in part, in the pathogenesis of TA in aortic grafts. Additional studies are needed to confirm the modulatory mechanism of NO during the development of TA.     

Overexpression of P104L mutant caveolin-3 in mice develops hypertrophic cardiomyopathy with enhanced contractility in association with increased endothelial nitric oxide synthase activity

The effect of endogenous nitric oxide synthase (NOS) on cardiac contractility and architecture has been a matter of debate. A role for NOS in cardiac hypertrophy has recently been demonstrated by studies which have shown hypertrophic cardiomyopathy (HCM) with altered contractility in constitutive NOS (cNOS) knockout mice. Caveolin-3, a strong inhibitor of all NOS isoforms, is expressed in sarcolemmal caveolae microdomains and binds to cNOS in vivo: endothelial nitric oxide synthase (eNOS) in cardiac myocytes and neuronal nitric oxide synthase (nNOS) in skeletal myocytes. The current study characterized the biochemical and cardiac parameters of P104L mutant caveolin-3 transgenic mice, a model of an autosomal dominant limb-girdle muscular dystrophy (LGMD1C). Transgenic mouse hearts demonstrated HCM, enhanced basal contractility, decreased left ventricular end diastolic diameter, and loss and cytoplasmic mislocalization of caveolin-3 protein. Surprisingly, cardiac muscle showed activation of eNOS catalytic activity without increased expression of all NOS isoforms. These data suggest that a moderate increase in eNOS activity associated with loss of caveolin-3 results in HCM.     

Evidence for a detrimental role of nitric oxide synthesized by endothelial nitric oxide synthase after peripheral nerve injury

Physical injury to a nerve is the most common cause of acquired peripheral neuropathy. Identification of molecules involved in degenerative and regenerative processes is a key step toward development of therapeutic tools in order to accelerate motor, sensory and/or autonomic function recovery. We have studied the role of nitric oxide (NO) using as a model the severe crushing of a motor nerve in adult rats. This type of injury up-regulates the three isoforms of nitric oxide synthase (NOS) in the affected nerve. Chronic systemic inhibition of NOS accelerated the onset of functional muscle reinnervation evaluated by the recording of compound muscle action potential evoked by electrical stimulation of the injured nerve. Besides, it increased the number of back-labeled motoneurons by application, 2 days after injury, of a retrograde marker 10 mm distal to the crushing site. These effects were mimicked by chronic specific inhibition of the endothelial isoform of nitric oxide synthase (eNOS), but not by specific inhibitors of the neuronal or inducible isoform. Next, we intraneurally injected a replication-deficient adenoviral vector directing the expression of a dominant negative mutant of eNOS (Ad-TeNOS). A single injection of Ad-TeNOS on the day of crushing significantly accelerated functional recovery of neuromuscular junction and increased axonal regeneration. Moreover, Ad-TeNOS did not compromise motoneuron viability or stability of reestablished neuromuscular junctions. Taken together, these results suggest that NO of endothelial origin slows down muscle reinnervation by means of detrimental actions on axonal regeneration after peripheral nerve injury. These experiments identify eNOS as a potential therapeutic target for treatment of traumatic nerve injuries and highlight the potential of gene therapy in treating injuries of this type using viral vectors to suppress the activity of eNOS.     

Age-related changes in nitric oxide synthase and arginase in the rat prefrontal cortex

Increasing evidence suggests that nitric oxide (NO), generated by nitric oxide synthase (NOS) from l-arginine, plays an important role in the ageing process. The present study, for the first time, investigates age-related changes in NOS and arginase, an enzyme that shares a common substrate with NOS, in the prefrontal cortex of rats assessed with and without prior behavioural testing. A significant increase in total NOS activity was found in the prefrontal cortex in aged (24-month-old) as compared with young (4-month-old) rats. Western blotting revealed that there were no significant differences between young and aged rats in neuronal NOS (nNOS) and endothelial NOS (eNOS) protein expression. Inducible isoform of NOS (iNOS), in terms of activity and protein expression, was not detected in either group. Total arginase activity and arginase I and II protein expression did not differ between the young and aged groups. The present findings support the contribution of NOS/NO to ageing but question the importance of iNOS in the normal ageing process.