大鼠实验性肝硬化门脉高压形成过程中内皮素及其转化酶的动态变化

目的 观察大鼠实验性肝硬化门脉高压形成过程中,外周血内皮素(ET-1)含量和肝脏前内皮素原(ppET-1)和内皮素转化酶(ECE)mRNA表达的动态变化,以期对其在门脉高压中动态变化的特点有进一步的了解。方法 通过四氯化碳(CCl4)介导大鼠实验性肝硬化门脉高压模型,放免法检测ET-1,半定量RT-PCR法观察不同时期肝组织中ppET-1和ECEmRNA的表达差异。结果 与对照组相比,模型组中外周血ET-1含量和肝脏ppET-1的表达分别从第8周和第6周开始显著升高,且ET-1的升高与门脉高压形成呈显著相关,而肝脏中ECE的表达无明显差异。结论 外周血中ET-1含量的增高和肝脏中ppET-1表达的增加可能是形成肝硬化门脉高压的重要原因之一。     

肝硬化大鼠肝脏及血浆内皮素水平的动态变化

目的:本研究观察大鼠肝组织及血浆内皮素(ET)水平在肝硬化门脉高压形成过程中的动态变化及其与门脉压力的关系。方法:经皮下注射四氯化碳制作大鼠肝硬化模型,于第0、5、7、9、11周各处死一批动物。以放免法测定肝组织及血浆ET含量,门脉压力用检压计测定。结果:在CCl_1诱导肝硬化过程中,各阶段大鼠肝组织及血浆ET含量均逐渐升高,经t检验有显著性差异(P均<0.01),其中血浆ET增加的幅度不如肝组织大。另外,肝组织ET含量与门脉压力有显著相关性(r=0.612,P<0.01)。结论:本研究结果提示:ET至少部分地通过其在肝内含量升高而增加肝内血管阻力,参与门脉高压的形成。     

ET-1与肝纤维化和肝硬化门脉高压的关系

目的研究血清内皮素-1（ET-1）与肝纤维化和肝硬化门脉高压的关系。方法选择60例肝炎肝硬化患者（观察组）和20例慢性肝炎患者（对照组）,检测两组ET-1水平,用彩色多普勒检测受试者门脉血流动力学的变化,分析ET-1在肝纤维化形成中的作用及其与肝硬化门脉高压的关系。结果观察组血清ET-1显著高于对照组（P〈0．01）,且随Child分级增加而增高;ET-1分别与HA、LN、PⅢP和ⅣC呈明显正相关;食管静脉曲张患者血清ET-1水平明显高于无静脉曲张者（P〈0．01）,ET-1与门静脉血流量和脾静脉血流量明显相关（r=0．721,0．774;P均〈0．05）。结论ET-1在肝硬化门脉血流动力学紊乱的形成中起重要作用,血清ET-1检测可反映肝纤维化和肝硬化程度;ET-1拮抗剂可能是肝硬化治疗的新途径。     

大鼠肝前型门脉高压症形成中门静脉结构的动态变化

目的探讨大鼠肝前型门脉高压症形成中门静脉血管结构的动态变化及意义。方法以部分门静脉结扎（PVL）法复制肝前型门脉高压症大鼠模型，采用组织形态学方法及计算机图像分析技术测定PVL术后1、2、4、8、12、16、20、26天大鼠的门静脉内径（ID）、外径（OD）、壁厚（WT）、壁面轵（CSA）及平滑肌含量（SMC），同步监测大鼠门静脉压力（PVP）、门静脉血流量（PVF）、平均动脉压（MAP）、门静脉阻力（PVR）、内赃血管阻力（SVR）等血液动力学参数的动态变化。结果PVL术后，大鼠的PVP、PVR、SVR、MAP发生了显著变化。PVL大鼠门静脉CSA从术后12d起，ID、OD、WT和SMC从术后16d起较对照组显著增加（P〈0．05）。结论门脉高压大鼠存在高动力循环状态（HCS）。HCS可引起门静脉结构变化，其管壁增厚，内外管径增大，平滑肌增生。     

实验性肝硬化血浆内毒素、一氧化氮与内皮素的含量变化及其意义

目的：通过观察实验性肝硬化形成过程内毒素,一氧化氮（ＮＯ）与内皮素（ＥＴ）与内皮素（ＥＴ）的动态变化,探讨其与肝硬化高动力循环状态的关系。方法：采用鲎试剂基质显色法,镉还原比色法和放射免疫分析法测定了四氯化碳（ＣＣＩ＾４）诱发大鼠肝硬变形过程中血浆内毒素,ＮＯ,ＥＴ含量变化。结果：在肝硬化进程中血浆内毒素,ＮＯ含量呈上升趋势且明显高于正常对照组（Ｐ〈０．０１）,血浆ＥＴ含量呈下降趋势且明显低于正常     

一氧化氮和内皮素与肝硬化并肝肾综合征患者血流动力学的关系

目的 探讨一氧化氮（ＮＯ）、内皮素（ＥＴ）与肝硬化并肝肾综合征患者血流动力学的关系。方法 选择２５例肝硬化合肝肾综合征（ＨＲＳ）患者为观察组,３０例肝硬化无ＨＲＳ患者为对照组,ＮＯ通过检测其代谢产物硝酸盐而间接测定,ＥＴ利用放射免疫法测定。结果 ＨＲＳ患者血ＮＯ,２４小时尿ＮＯ、ＥＴ水平较无ＨＲＳ组升高,而平均动脉压（ＭＢＰ）则明显降低。血、尿ＮＯ与门脉血流量（ＰＱ）、心输出量（ＣＯ）、心脏指数（     

肝硬化门脉血流动力学与一氧化氮、内皮素

探讨肝硬化患者门脉血液动力学与血中 ＮＯ、ＥＴ的相互关系。４８例肝硬化门脉高压患者（代偿期 １８例，失代偿期３０例）及３２例正常人作为研究对象，应用双功多普勒测定门、脾静脉血流量（ＰＶＢＦ＆ＳＶＢＦ），同步测定血中ＮＯ，ＥＴ的水平，分析ＰＶＢＦ、ＳＶＢＦ与ＮＯ、ＥＴ的相关性。门脉系统高血流动力学改变存在于肝硬化门脉高压发病的始终，其形成原因可能在于体内扩血管活性物质ＮＯ的生成增多，及机体对ＥＴ等缩血管物质的敏感性下降，对临床治疗有指导意义。     

软肝冲剂对肝炎肝硬化门脉高压患者血清一氧化氮、内皮素的影响

目的：观察软肝冲剂对肝炎肝硬化门脉高压患者门静脉主干内径及血流量、血流速度和血清一氧化氮（NO），内皮素（ET）的影响。方法：选择肝炎肝硬化门脉高压患者97例，随机分为两组，治疗组口服软肝冲剂，对照级以西药常规治疗，观察治疗后的总有效率、肝功能，门静脉主干内径及血流量、血流速度和血清NO、ET的变化。结果：经治疗后治疗组总有效率优于对照组（P＜0．05），患者ANT，TBil明显降低，Alb和A／G均明显升高，门静脉内径变窄，血流量增多，血流速度变快，同时NO及ET亦显著降低，与对照组比较，差异有显著性意义（P＜0．05或0．01）。结论：软肝冲剂治疗肝炎肝硬化门脉高压疗效显著，能明显改善肝功能，降低门静脉压力，其作用机制之一是降低血清NO、ET水平。     

肝硬化患者血浆一氧化氮及内皮素改变的初步研究

肝硬化患者血浆一氧化氮及内皮素改变的初步研究黄永辉周力张晓蕾芦源陈晓琴肝硬化患者的病理生理及血液动力学改变受着多种因素的影响。内源性一氧化氮（ＮＯ）及内皮素（ＥＴ）是两种生理作用相互拮抗的血管活性物质。我们测定了３４例肝炎后肝硬化患者的血浆ＮＯ－２／...     

肝前性门静脉高压大鼠NO、CO与高动力循环的关系

目的 观察肝前性门静脉高压大鼠血中一氧化氮（NO）、碳氧血红蛋白（COHb)与血液循环动力指标的关系。方法 制作门静脉高压大鼠模型和假手术组模型。分别检测血中NO、COHb浓度，测定门静脉压力。血流和平均动脉压。结果 门静脉高压组大鼠血中NO、COHb浓度均较假手术组高，门静脉高压组大鼠门静脉压增高，门静脉血流减少及平均动脉压降低，血中NO、CO-Hb水平分别与门静脉压力呈正相关，与门静脉血流和平均动脉压呈负相关。结论 NO、一氧化碳（CO）的过度形成和释放对门静脉高压的形成和维持起重要作用。     

Current concepts on the role of nitric oxide in portal hypertension

Portal hypertension(PHT) is defined as a pathological increase in portal venous pressure and frequently accompanies cirrhosis.Portal pressure can be increased by a rise in portal blood flow,an increase in vascular resistance,or the combination.In cirrhosis,the primary factor leading to PHT is an increase in intra-hepatic resistance to blood flow.Although much of this increase is a mechanical consequence of architectural disturbances,there is a dynamic and reversible component that represents up to a third of the increased vascular resistance in cirrhosis.Many vasoactive substances contribute to the development of PHT.Among these,nitric oxide(NO) is the key mediator that paradoxically regulates the sinusoidal(intra-hepatic) and systemic/splanchnic circulations.NO deficiency in the liver leads to increased intra-hepatic resistance while increased NO in the circulation contributes to the hyperdynamic systemic/splanchnic circulation.NO mediated-angiogenesis also plays a role in splanchnic vasodilation and collateral circulation formation.NO donors reduce PHT in animals models but the key clinical challenge is the development of an NO donor or drug delivery system that selectively targets the liver.     

Overproduction of nitric oxide inhibits vascular reactivity in portal hypertensive rats

ＯｖｅｒｐｒｏｄｕｃｔｉｏｎｏｆｎｉｔｒｉｃｏｘｉｄｅｉｎｈｉｂｉｔｓｖａｓｃｕｌａｒｒｅａｃｔｉｖｉｔｙｉｎｐｏｒｔａｌｈｙｐｅｒｔｅｎｓｉｖｅｒａｔｓＬＩＸｉＲｕ,ＷＵＪｉｎＳｈｅｎｇ,ＨＥＺｅＳｈｅｎｇ,ＭＡＱｉｎｇＪｉｕａｎｄＧＡＯ...     

Evidence against a role for endotoxin in the hyperdynamic circulation of rats with prehepatic portal hypertension

BACKGROUND/AIMS: Excessive formation of nitric oxide may mediate the generalized vasorelaxation and hyporesponsiveness to vasoconstrictors observed in portal hypertensive states. Endotoxin, released from the bowel and detoxified by the liver, could stimulate inducible nitric oxide synthase directly or indirectly via the cytokine cascade. This study investigated the effect of chronic intraperitoneal injection of polymyxin B, a neutralizing antagonist of endotoxin, on the hemodynamics of partially portal vein-ligated (PVL) rats. METHODS: Concomitantly with endotoxin (600 EU) and dactinomycin (80 microg), polymyxin B (0.1 mg) or normal saline (N/S) was administered via an intraperitoneal route to male Sprague-Dawley rats. Twenty-four hours later, mean arterial pressure was determined. In PVL rats polymyxin B (0.1 mg in 5 cc N/S) or N/S was given intraperitoneally twice daily from 2 days prior to operation until 5 days (short-term) or 14 days (long-term) after the operation. Long-term polymyxin B- or N/S-treated sham-operated rats were included as controls. Hemodynamic studies with a thermodilution technique were performed at the end of treatment. Blood samples were collected from another series of PVL rats with long-term treatment to determine plasma levels of endotoxin and tumor necrosis factor-alpha. Plasma levels of endotoxin and tumor necrosis factor-alpha were measured by Limulus assay and the ELISA method, respectively. RESULTS: With the dosage of 0.1 mg polymyxin B, hypotension in rats subjected to endotoxin and dactinomycin administration could be corrected (polymyxin B vs. placebo: 130.0+/-7.7 vs. 108.8+/-6.7 mm Hg, p<0.05). However, long-term or short-term treatment with the same dosage of polymyxin B failed to ameliorate the hyperdynamic circulation of PVL rats. In addition, long-term treatment with polymyxin B did not change systemic and portal hemodynamics in sham-operated rats. Plasma levels of endotoxin and tumor necrosis factor-alpha were comparable in PVL rats treated with long-term polymyxin B or N/S (p>0.05). CONCLUSIONS: Our findings do not support the role of endotoxin in the hyperdynamic circulation of PVL rats.     

内源性H2S对大鼠实验性肝硬化门脉高压的影响

目的:研究新型气体信号分子硫化氢(hydrogensulfide,H<,2>S)对大鼠肝硬化门脉高压的影响及其调节机制.方法:对照组(8只),肝硬化(Cirrhosis,C)组(8只),C+NaHS(C+S)组(8只),C+左旋硝基精氨酸甲酯(L-NAME+锌原卟啉(ZnPP)(C+L+Zn)组(8只),C+NaHS+...     

硫化氢供体对实验性门静脉高压及内源性一氧化氮/一氧化氮合酶体系的影响

目的探讨硫化氢供体一硫氢化钠（sodium hydrosulfide，NaHS）对大鼠门静脉高压及内源性一氧化氮（nitric monoxide，NO）／一氧化氮合酶（nitricoxide synthase，NOS）体系的影响。方法将30只健康成年雄性sD大鼠随机分为4组：部分门静脉结扎（partly portal vein ligation，PPVL）组（10只）、PPVL＋NariS组（10只）、假手术组（5只）和正常组（5只）。PPVL组和PPVL＋NaHS组行部分门静脉结扎术建立门静脉高压的动物模型。模型制作14天后，分别测定各组大鼠的门静脉压力（PVP）和平均动脉压力（MAP）；采用免疫组织化学检测大鼠肝细胞中一氧化氮合酶（NOS2、NOSS）的蛋白水平表达情况，RT-PCR方法检测大鼠肝组织中NOS2和NOS3的mRNA水平的表达情况。结果术后14d，假手术组和正常组比较，各项检测指标无显著差异，NOS2蛋白及mR-NA水平未见明显表达；NOS3蛋白及mRNA表达水平无显著差异。PPVL组与假手术组比较，PVP明显升高（P〈0．05），MAP则下降（P〈0．05），PPVL＋NaHS组与PPVL组相比较，PVP进一步升高（P〈0．05），MAP则进一步降低（P〈0．05）。PPVL组和PPVL＋NaHS组NOS2在蛋白及mRNA水平均有表达，且后者NOS2蛋白及mRNA表达水平减少（P〈0．05）。4组之间NOS3的蛋白及mRNA表达水平则无显著差异。结论H2S参与了门静脉高压的形成与发展，NaHS可以加重门静脉高压，其作用可能与NO／NOS2体系有关。．     

Murine study of portal hypertension associated endothelin-1 hypo-response

AIM:To investigate endothelin-1 hypo-responsive associated with portal hypertension in order to improve patient treatment outcomes.METHODS:Wild type,e NOS-/-and i NOS-/-mice receivedpartial portal vein ligation surgery to induce portal hypertension or sham surgery.Development of portal hypertension was determined by measuring the splenic pulp pressure,abdominal aortic flow and portal systemic shunting.To measure splenic pulp pressure,a microtip pressure transducer was inserted into the spleen pulp.Abdominal aortic flow was measured by placing an ultrasonic Doppler flow probe around the abdominal aorta between the diaphragm and celiac artery.Portal systemic shunting was calculated by injection of fluorescent microspheres in to the splenic vein and determining the percentage accumulation of spheres in liver and pulmonary beds.Endothelin-1 hypo-response was evaluated by measuring the change in abdominal aortic flow in response to endothelin-1 intravenous administration.In addition,thoracic aorta endothelin-1contraction was measured in 5 mm isolated thoracic aorta rings ex-vivo using an ADI small vessel myograph.RESULTS:In wild type and i NOS-/-mice splenic pulp pressure increased from 7.5±1.1 mm Hg and 7.2±1 mm Hg to 25.4±3.1 mm Hg and 22±4 mm Hg respectively.In e NOS-/-mice splenic pulp pressure was increased after 1 d(P=NS),after which it decreased and by 7 d was not significantly elevated when compared to 7 d sham operated controls(6.9±0.6 mm Hg and 7.3±0.8 mm Hg respectively,P=0.3).Abdominal aortic flow was increased by 80%and 73%in 7 d portal vein ligated wild type and i NOS when compared to shams,whereas there was no significant difference in 7 d portal vein ligated e NOS-/-mice when compared to shams.Endothelin-1 induced a rapid reduction in abdominal aortic blood flow in wild type,e NOS-/-and i NOS-/-sham mice(50%±8%,73%±9%and 47%±9%respectively).Following portal vein ligation endothelin-1 reduction in blood flow was significantly diminished in each mouse group.Abdominal aortic flow was reduced by 19%±9%,32%±10%and 9%±9%in wild type,e NOS-/-and i NOS-/-mice respectively.CONCLUSION:Aberrant endothelin-1 response in murine portal hypertension is NOS isoform independent.Moreover,portal hypertension in the portal vein ligation model is independent of ET-1 function.     

Physiopathology of splanchnic vasodilation in portal hypertension

In liver cirrhosis, the circulatory hemodynamic alterations of portal hypertension significantly contribute to many of the clinical manifestations of the disease. In the physiopathology of this vascular alteration, mesenteric splanchnic vasodilation plays an essential role by initiating the hemodynamic process. Numerous studies performed in cirrhotic patients and animal models have shown that this splanchnic vasodilation is the result of an important increase in local and systemic vasodilators and the presence of a splanchnic vascular hyporesponsiveness to vasoconstrictors. Among the molecules and factors known to be potentially involved in this arterial vasodilation, nitric oxide seems to have a crucial role in the physiopathology of this vascular alteration. However, none of the wide variety of mediators can be described as solely responsible, since this phenomenon is multifactorial in origin. Moreover, angiogenesis and vascular remodeling processes also seem to play a role. Finally, the sympathetic nervous system is thought to be involved in the pathogenesis of the hyperdynamic circulation associated with portal hypertension, although the nature and extent of its role is not completely understood. In this review, we discuss the different mechanisms known to contribute to this complex phenomenon.     

Role of PGI2 in the formation and maintenance of hyperdynamic circulatory state of portal hypertensive rats

AIM: To investigate the role of prostacyclin (PGI2) and nitric oxide (NO) in the development and maintenance of hyperdynamic circulatory state of chronic portal hypertensive rats. METHODS: Ninety male Sprague-Dawley rats were divided into three groups: intrahepatic portal hypertension (IHPH) group by injection of CCI4, prehepatic portal hypertension (PHPH) group by partial stenosis of the portal vein and sham-operation control (SO) group. One week after the models were made, animals in each group were subdivided into 4 groups: saline controlled group (n = 23), Nω-nitro-L-arginine (L-NNA)group (n = 21) group, indomethacin (INDO) group (n = 22) and high-dose heparin group (n = 24). The rats were administrated 1mL of saline, L-NNA (3.3 mg/kg-d) and INDO (5 mg/kg·d) respectively through gastric tubes for one week/then heparin (200 IU/Kg/min) was given to rats by intravenous injection for an hour. Splanchnic and systemic hemodynamics were measured using radioactive microsphere techniques. The serum nitrate/nitrite(NO2-/NO3-) levels as a marker of production of NO were assessed by a colorimetric method, and concentration of 6-keto-PGF1α, a stable hydrolytic product of PGI2, was determined by radioimmunoassay. RESULTS: The concentrations of plasma 6-keto-PGFla (pg/mL) and serum NO2-/NO3- (μmol/L) in IHPH rats (1123.85±153.64, 73.34±4.31) and PHPH rats (891.88±83.11, 75.21±6.89) were significantly higher than those in SO rats (725.53±105.54, 58.79±8.47) (P<0.05). Compared with SO rats, total peripheral vascular resistance (TPR) and spanchnic vascular resistance (SVR) decreased but cardiac index (CI) and portal venous inflow (PVI) increased obviously in IHPH and PHPH rats (P<0.05). L-NNA and indomethacin could decrease the concentrations of plasma 6-keto-PGFla and serum NO2/7NO3-in IHPH and PHPH rats (P<0.05) .Meanwhile, CI, FPP and PVI lowered but MAP, TPR and SVR increased(P<0.05). After deduction of the action of NO, there was no significant correlation between plasma PGI2 level and hemodynamic parameters such as CI, TPR, PVI and SVR. However, after deduction of the action of PGI2, NO still correlated highly with the hemodynamic parameters, indicating that there was a close correlation between NO and the hemodynamic parameters. After administration of high-dose heparin, plasma 6-keto- concentrations in IHPH, PHPH and SO rats were significantly higher than those in rats administrated vehicle (P<0.05). On the contrary, levels of serum NO2-/NO3- in IHPH, PHPH and SO rats were significantly lower than those in rats administrated Vehicle (P<0.05). Compared with those rats administrated vehicle, the hemodynamic parameters of portal hypertensive rats, such as CI and PVI, declined significantly after administration of high-dose heparin (P<0.05), while TPR and SVR increased significantly (P<0.05). CONCLUSION: It is NO rather than PGI2 that is a mediator in the formation and maintenance of hyperdynamic circulatory state of chronic portal hypertensive rats.     

诱导型和内皮型一氧化氮合酶基因多态性与肝硬化门静脉高压的相关性

目的探讨诱导型一氧化氮合酶(iNOS)和内皮型一氧化氮合酶(eNOS)基因多态性与肝硬化门静脉高压的相关性。方法采用病例对照和聚合酶链反应-限制性片段长度多态性技术,检测106 例乙型肝炎后肝硬化患者(其中门静脉高压症65例)和108名健康对照者iNOS基因启动子-969G→C多态性及eNOS基因第七外显子894G→多态性,比较等位基因及基因型频率,并进行综合分析。结果在iNOS启动子969G→C多态性中,门静脉高压症组C等位基因和GC基因型频率比对照组显著升高(x2- 5.93,P<0.05)。GC基因型启动子的活性比GG基因型活性强。在eNOS的894G→T多态性中,T等位基因频率明显高于对照组(x2-3.91,P<0.05)。采用Logistic多元回归显示iNOS基因启动子-969G→C多态性及cNOS的894G→T多态性是门静脉高压症新的危险因素。结论iNOS启动子969G→C多态性和eNOS的894G→T多态性与门静脉高压症相关,是形成门静脉高压症新的危险因素。iNOS启动子-969G→C多态性可导致该基因启动子功能活性增强。