Objective To investigate the effects of hemoglobin (Hb) on serum nitric oxide (ON) concentrationand hemodynamics pattern changes in rats with cirrhosis. Methods Cirrhosis model was induced in male SDrats by injection ...Objective To investigate the effects of hemoglobin (Hb) on serum nitric oxide (ON) concentrationand hemodynamics pattern changes in rats with cirrhosis. Methods Cirrhosis model was induced in male SDrats by injection of 60% CCl4 oily solution subcutaneously. Cirrhotic rats were treated with erythropoietin(100U/kg) injected subcutaneously for 2 weeks. Mean arterial pressure (MAP), cardiac output (CO), cardiac index(CI), splanchnic vascular resistance (SVR), splanchnic blood flow (SBF) and serum NO concentration weredetermined in erythropoietin - treated, erythropoietin - untreated cirrhotic rats and controls by using 57Co - labelledmicrosphere technique and a fluorometric assay, respectively. In addition, blood Hb levels were also measured inthe 3 groups. Results Untreated cirrhotic rats had significantly lower MAP, SVR, Hb and higher Co, CI, SBFand NO concentration than those of the controls (P<0.01). In treated cirrhotic rats, erythropoietin significantlyattenuated the increase of CO, CI, SBF, NO concentration and the decrease of MAP and SVR. In cirrhotic rats,opoetin beta in subcutaneous dose of 100U·kg-1·d-1 induced a markedly increment of blood Hb levels anddecrement of NO concentration in comparison with untreated cirrhotic rats (181±11g/L vs 120±15g/L,1.14±0.62μmol/L vs 4.20±1.25μmol/L). Conclusion The endogenous NO may play an important role in thechanges of hemodynamics pattern in cirrhosis, and hyperdynamic circulatory status in rats with cirrhosis might beameliorated by inactivation of overproduced NO by increasing hemoglobin with erythropoietin.展开更多
AIM To observe the nitric oxide synthase (NOS) distribution in the esophageal mucosa andhemodynamic changes in cirrhotic rats.METHODS NOS distribution in the loweresophagus of rats with carbon tetrachlorideinduced cir...AIM To observe the nitric oxide synthase (NOS) distribution in the esophageal mucosa andhemodynamic changes in cirrhotic rats.METHODS NOS distribution in the loweresophagus of rats with carbon tetrachlorideinduced cirrhosis was assessed by using NADPHdiaphorase (NADPH-d ) histochemical method.Concentration of NO in serum were measured byfluorometric assay. Mean arterial pressure(MAP), cardiac output (CO), cardiac index (CI),splanchnic vascular resistance (SVR ), andsplanchnic blood flow (SBF ) were alsodetermined using 5’CO-labeled microspheretechnique.RESULTS Intensity of NOS staining in theesophageal epithelium of cirrhotic rats wassignificantly stronger than that in controls.There was a NOS--positive staining area in theendothelia of esophageal submucosal vessels ofcirrhotic rats, but the NOS staining was negativein normal rats. NO concentration of serum incirrhotic rats were significantly higher incomparison with that of controls. Cirrhotic ratshad significantly lower MAP, SVR and higherSBF than those of the controls.CONCLUSION SPlanchnic hyperdynamiccirculatory state was observed in rats withcirrhosis. The endogenous NO may play animportant role in development of esophagealvarices and in changes of hemodynamics incirrhosis.展开更多
OBJECTIVE: To determine the effect of Salviae miltiorrhizae on cirrhosis and portal hyperiension by inhibiting nitric oxide synthase type Ⅱ (NOSⅡ) in rats. METHODS: Real time RT-PCR was used to detect the expression...OBJECTIVE: To determine the effect of Salviae miltiorrhizae on cirrhosis and portal hyperiension by inhibiting nitric oxide synthase type Ⅱ (NOSⅡ) in rats. METHODS: Real time RT-PCR was used to detect the expression of NOSII mRNA. The enzymatic activity of nitric oxide synthase and the circulating levels of nitric oxide (NO), systemic and portal hemodynamics, and quantification of cirrhosis were measured with highly sensitive methods. Traditional Chinese medicine was utilized to treat cirrhotic rats and the function of NO was evaluated. Double-blind method was applied in the experiment constantly. RESULTS: The concentration of NO increased markedly at all stages of cirrhosis, and so did the enzymatic activity of NOS, antl the iNOSmRNA expressed greatly. Meanwhile the portal-venous-pressure (PVP), portal-venous-now (PVF) increased significantly. NO, Nos and iNOSmHNA were positively correlated to the quanlity of hepatic fihrosis. Salviae Miltiorrhizae significantly inhibited NO production and inhibited the expression of iNOSmRNA. CONCLUSIONS: The increased hepatic expression of NoSIⅡ is one of the important factors causing cirrhosis and portal hypertension. Salviae Miltiorrhizae significantly ameliorates cirrhosis and portal hypertension.展开更多
AIM To investigate the potential effect of inhibitors of phosphodiesterase-5(PDE-5) for therapy of portal hypertension in liver cirrhosis.METHODS In the rat model of thioacetamide-induced liver fibrosis/cirrhosis the ...AIM To investigate the potential effect of inhibitors of phosphodiesterase-5(PDE-5) for therapy of portal hypertension in liver cirrhosis.METHODS In the rat model of thioacetamide-induced liver fibrosis/cirrhosis the nitric oxide-cyclic guanosine monophosphate(NO-cGMP) pathway was investigated. Expression and localization of PDE-5, the enzyme that converts vasodilating cGMP into inactive 5'-GMP, was in the focus of the study. Hepatic gene expression of key components of the NO-cGMP pathway was determined by qRT-PCR: Endothelial NO synthase(eNOS), inducible NO synthase(iNOS), soluble guanylate cyclase subunits α1 and β1(sGCa1, sGCb1), and PDE-5. Hepatic PDE-5 protein expression and localization were detected by immunohistochemistry. Serum cGMP concentrations were measured using ELISA. Acute effects of the PDE-5 inhibitor Sildenafil(0.1 mg/kg or 1.0 mg/kg) on portal and systemic hemodynamics were investigated using pressure transducers.RESULTS Hepatic gene expression of eNOS(2.2-fold; P = 0.003), sGCa1(1.7-fold; P = 0.003), sGCb1(3.0-fold; P = 0.003), and PDE-5(11-fold; P = 0.003) was increased in cirrhotic livers compared to healthy livers. Overexpression of PDE-5(7.7-fold; P = 0.006) was less pronounced in fibrotic livers. iNOS expression was only detected in fibrotic and cirrhotic livers. In healthy liver, PDE-5 protein was localized primarily in zone 3 hepatocytes and to a lesser extent in perisinusoidal cells. This zonation was disturbed in cirrhosis: PDE-5 protein expression in perisinusoidal cells was induced approximately 8-fold. In addition, PDE-5-expressing cells were also found in fibrous septa. Serum cGMP concentrations were reduced in rats with cirrhotic livers by approximately 40%. Inhibition of PDE-5 by Sildenafil caused a significant increase in serum cGMP concentrations [+ 64% in healthy rats(P = 0.024), + 85% in cirrhotic rats(P = 0.018)]. Concomitantly, the portal venous pressure was reduced by 19% in rats with liver cirrhosis. CONCLUSION Overexpression and abrogated zonation of PDE-5 likely contribute to the pathogenesis of cirrhotic portal hypertension. PDE-5 inhibition may therefore be a reasonable therapeutic approach for portal hypertension.展开更多
To examine the role and effect of nitric oxide synthase type Ⅱ(NOSⅡ) in cirrhotic rats, expression of NOSⅡ mRNA was detected by real time RT-PCR. The enzymatic activity of nitric oxide synthase and the circulating ...To examine the role and effect of nitric oxide synthase type Ⅱ(NOSⅡ) in cirrhotic rats, expression of NOSⅡ mRNA was detected by real time RT-PCR. The enzymatic activity of nitric oxide synthase and the circulating levels of NO, systemic and portal hemodynamics and quantification of cirrhosis were measured. Chinese traditional medicine was used to treat cirrhotic rats and the effect of NO was evaluated. Double-blind method was used in experiment. Our results showed the concentration of NO and the enzymatic activity of NOS increased markedly at all stages of cirrhosis and iNOSmRNA was strongly expressed. Meanwhile, the portal-venous-pressure (PVP) and portal-venous-flow (PVF) were significantly increased. NO, NOS and iNOSmRNA were positively correlated to the degree of hepatic fibrosis. Tetrandrine significantly inhibited NO production and the expression of iNOSmRNA. Our results suggested that increased hepatic expression of NOSⅡ is one of the important factors causing cirrhosis and portal hypertension. Tetrandrine can significantly ameliorate cirrhosis and portal hypertension.展开更多
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 res...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.展开更多
The levels of plasma nitric oxide (NO), endothelin 1 (ET 1) and ALT in the patients with chronic hepatitis B and active cirrhosis and the correlation among them were observed and analyzed. NO 3 ˉ was restored by ...The levels of plasma nitric oxide (NO), endothelin 1 (ET 1) and ALT in the patients with chronic hepatitis B and active cirrhosis and the correlation among them were observed and analyzed. NO 3 ˉ was restored by using cadmium column assay and NO 2 ˉ measured by heavy nitrogen assay. The primitive NO 3 ˉ and total restored NO 2 ˉ(NO 3 ˉ/ NO 2 ˉ) in plasma of the patients with chronic hepatitis and cirrhosis. Plasma ET 1 and ALT levels were determined by using radioimmunological assay and Lai's assay, respectively. Compared with normal control group, the plasma levels of NO 2 ˉ/NO 3 ˉ and ET 1 in the patients with chronic active hepatitis and active cirrhosis were significantly increased ( P <0.05-0.01). There was a positive correlation between NO and ALT, and ET 1 and ALT in the patients with chronic active hepatitis and active cirrhosis respectively. It was suggested that elevation of both NO and ET 1 levels were closely related with injury severity of liver function.展开更多
This review describes the recent developments in the pathobiology of endothelial dysfunction(ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED ...This review describes the recent developments in the pathobiology of endothelial dysfunction(ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. EDcharacterised by an impaired bioactivity of nitric oxide(NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase(e NOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of e NOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.展开更多
目的:研究内源性一氧化氮(nitric oxide,NO)/一氧化氮合酶(nitricoxide synthase,NOS)体系及一氧化碳(carbonic oxide,CO)/血红素合酶(heme oxygenase,HO-1)体系对肝硬化大鼠门静脉压力的影响,探讨NO/NOS体系及CO/HO-1体系在大鼠肝硬化...目的:研究内源性一氧化氮(nitric oxide,NO)/一氧化氮合酶(nitricoxide synthase,NOS)体系及一氧化碳(carbonic oxide,CO)/血红素合酶(heme oxygenase,HO-1)体系对肝硬化大鼠门静脉压力的影响,探讨NO/NOS体系及CO/HO-1体系在大鼠肝硬化门静脉高压中的作用.方法:将SD大鼠随机分为4组:正常对照组(N C组)、正常对照+左旋硝基精氨酸甲酯(L-NAME)+锌原卟啉-Ⅸ(Znpp-Ⅸ)组(NC+LNAME+ZnPP-Ⅸ组)、肝硬化模型组(CIRM组)、肝硬化模型+左旋硝基精氨酸甲酯(L-NAME)+锌原卟啉-Ⅸ(Znpp-Ⅸ)组(CIRM+LNAME+ZnPP-Ⅸ组).均用插管法测定门静脉压力,用硝酸还原酶法测定血浆中NO含量,联二亚硫酸盐还原法测定血浆CO含量,运用蛋白免疫印迹技术(Western blot)测定肝组织中内皮细胞一氧化氮合酶(endothelial nitricoxide synthase,e N O S)、诱导型一氧化氮合酶(i n duc i b l e nitricoxide synthase,iNOS)及HO-1蛋白的表达情况.结果:与NC组相比,CIRM组血浆NO、CO含量明显升高(160.12μmol/L±4.18μmol/L,111.12μmol/L±2.26μmol/L vs 81.11μmol/L±2.91μmol/L,70.51μmol/L±3.10μmol/L,均P<0.01),门静脉压力明显升高(16.08 mmHg±1.16 mmHg vs 9.85 mmHg±1.10 mmHg,P<0.01),肝组织中iNOS及HO-1蛋白含量明显升高(165.69±1.17,155.79±1.29 vs 135.22±0.54,125.44±0.94,均P<0.01),但eNOS在肝组织的表达却明显降低(118.65±1.29 vs 160.77±2.12,P<0.01),而NC+L-NAME+ZnPP-Ⅸ组NO、CO含量则明显降低(52.06μmol/L±3.17μmol/L,52.51μmol/L±2.63μmol/L,均P<0.01),门静脉压力无统计学意义,肝组织中eNOS、iNOS及HO-1蛋白含量亦明显降低(130.83±1.57,120.81±1.47,111.03±1.45,均P<0.01);与CIRM组相比,CIRM+L-NAME+ZnPP-Ⅸ组血浆NO、CO含量明显降低(100.24μmol/L±3.80μmol/L,83.73μmol/L±1.78μmol/L,均P<0.01),门静脉压力明显降低(14.13 mmHg±0.56 mmHg,P<0.01),肝组织中eNOS、iNOS及HO-1蛋白含量明显降低(87.50±1.07,150.66±1.42,139.88±1.73,均P<0.01).结论:NO、CO作为新型气体信号分子,与肝硬化门静脉压力的变化密切相关,而NO、CO抑制剂的干预研究则进一步证明了内源性NO/NOS体系及CO/HO-1体系对肝硬化门静脉高压的形成具有重要的调节作用.展开更多
文摘Objective To investigate the effects of hemoglobin (Hb) on serum nitric oxide (ON) concentrationand hemodynamics pattern changes in rats with cirrhosis. Methods Cirrhosis model was induced in male SDrats by injection of 60% CCl4 oily solution subcutaneously. Cirrhotic rats were treated with erythropoietin(100U/kg) injected subcutaneously for 2 weeks. Mean arterial pressure (MAP), cardiac output (CO), cardiac index(CI), splanchnic vascular resistance (SVR), splanchnic blood flow (SBF) and serum NO concentration weredetermined in erythropoietin - treated, erythropoietin - untreated cirrhotic rats and controls by using 57Co - labelledmicrosphere technique and a fluorometric assay, respectively. In addition, blood Hb levels were also measured inthe 3 groups. Results Untreated cirrhotic rats had significantly lower MAP, SVR, Hb and higher Co, CI, SBFand NO concentration than those of the controls (P<0.01). In treated cirrhotic rats, erythropoietin significantlyattenuated the increase of CO, CI, SBF, NO concentration and the decrease of MAP and SVR. In cirrhotic rats,opoetin beta in subcutaneous dose of 100U·kg-1·d-1 induced a markedly increment of blood Hb levels anddecrement of NO concentration in comparison with untreated cirrhotic rats (181±11g/L vs 120±15g/L,1.14±0.62μmol/L vs 4.20±1.25μmol/L). Conclusion The endogenous NO may play an important role in thechanges of hemodynamics pattern in cirrhosis, and hyperdynamic circulatory status in rats with cirrhosis might beameliorated by inactivation of overproduced NO by increasing hemoglobin with erythropoietin.
文摘AIM To observe the nitric oxide synthase (NOS) distribution in the esophageal mucosa andhemodynamic changes in cirrhotic rats.METHODS NOS distribution in the loweresophagus of rats with carbon tetrachlorideinduced cirrhosis was assessed by using NADPHdiaphorase (NADPH-d ) histochemical method.Concentration of NO in serum were measured byfluorometric assay. Mean arterial pressure(MAP), cardiac output (CO), cardiac index (CI),splanchnic vascular resistance (SVR ), andsplanchnic blood flow (SBF ) were alsodetermined using 5’CO-labeled microspheretechnique.RESULTS Intensity of NOS staining in theesophageal epithelium of cirrhotic rats wassignificantly stronger than that in controls.There was a NOS--positive staining area in theendothelia of esophageal submucosal vessels ofcirrhotic rats, but the NOS staining was negativein normal rats. NO concentration of serum incirrhotic rats were significantly higher incomparison with that of controls. Cirrhotic ratshad significantly lower MAP, SVR and higherSBF than those of the controls.CONCLUSION SPlanchnic hyperdynamiccirculatory state was observed in rats withcirrhosis. The endogenous NO may play animportant role in development of esophagealvarices and in changes of hemodynamics incirrhosis.
文摘OBJECTIVE: To determine the effect of Salviae miltiorrhizae on cirrhosis and portal hyperiension by inhibiting nitric oxide synthase type Ⅱ (NOSⅡ) in rats. METHODS: Real time RT-PCR was used to detect the expression of NOSII mRNA. The enzymatic activity of nitric oxide synthase and the circulating levels of nitric oxide (NO), systemic and portal hemodynamics, and quantification of cirrhosis were measured with highly sensitive methods. Traditional Chinese medicine was utilized to treat cirrhotic rats and the function of NO was evaluated. Double-blind method was applied in the experiment constantly. RESULTS: The concentration of NO increased markedly at all stages of cirrhosis, and so did the enzymatic activity of NOS, antl the iNOSmRNA expressed greatly. Meanwhile the portal-venous-pressure (PVP), portal-venous-now (PVF) increased significantly. NO, Nos and iNOSmHNA were positively correlated to the quanlity of hepatic fihrosis. Salviae Miltiorrhizae significantly inhibited NO production and inhibited the expression of iNOSmRNA. CONCLUSIONS: The increased hepatic expression of NoSIⅡ is one of the important factors causing cirrhosis and portal hypertension. Salviae Miltiorrhizae significantly ameliorates cirrhosis and portal hypertension.
文摘AIM To investigate the potential effect of inhibitors of phosphodiesterase-5(PDE-5) for therapy of portal hypertension in liver cirrhosis.METHODS In the rat model of thioacetamide-induced liver fibrosis/cirrhosis the nitric oxide-cyclic guanosine monophosphate(NO-cGMP) pathway was investigated. Expression and localization of PDE-5, the enzyme that converts vasodilating cGMP into inactive 5'-GMP, was in the focus of the study. Hepatic gene expression of key components of the NO-cGMP pathway was determined by qRT-PCR: Endothelial NO synthase(eNOS), inducible NO synthase(iNOS), soluble guanylate cyclase subunits α1 and β1(sGCa1, sGCb1), and PDE-5. Hepatic PDE-5 protein expression and localization were detected by immunohistochemistry. Serum cGMP concentrations were measured using ELISA. Acute effects of the PDE-5 inhibitor Sildenafil(0.1 mg/kg or 1.0 mg/kg) on portal and systemic hemodynamics were investigated using pressure transducers.RESULTS Hepatic gene expression of eNOS(2.2-fold; P = 0.003), sGCa1(1.7-fold; P = 0.003), sGCb1(3.0-fold; P = 0.003), and PDE-5(11-fold; P = 0.003) was increased in cirrhotic livers compared to healthy livers. Overexpression of PDE-5(7.7-fold; P = 0.006) was less pronounced in fibrotic livers. iNOS expression was only detected in fibrotic and cirrhotic livers. In healthy liver, PDE-5 protein was localized primarily in zone 3 hepatocytes and to a lesser extent in perisinusoidal cells. This zonation was disturbed in cirrhosis: PDE-5 protein expression in perisinusoidal cells was induced approximately 8-fold. In addition, PDE-5-expressing cells were also found in fibrous septa. Serum cGMP concentrations were reduced in rats with cirrhotic livers by approximately 40%. Inhibition of PDE-5 by Sildenafil caused a significant increase in serum cGMP concentrations [+ 64% in healthy rats(P = 0.024), + 85% in cirrhotic rats(P = 0.018)]. Concomitantly, the portal venous pressure was reduced by 19% in rats with liver cirrhosis. CONCLUSION Overexpression and abrogated zonation of PDE-5 likely contribute to the pathogenesis of cirrhotic portal hypertension. PDE-5 inhibition may therefore be a reasonable therapeutic approach for portal hypertension.
文摘To examine the role and effect of nitric oxide synthase type Ⅱ(NOSⅡ) in cirrhotic rats, expression of NOSⅡ mRNA was detected by real time RT-PCR. The enzymatic activity of nitric oxide synthase and the circulating levels of NO, systemic and portal hemodynamics and quantification of cirrhosis were measured. Chinese traditional medicine was used to treat cirrhotic rats and the effect of NO was evaluated. Double-blind method was used in experiment. Our results showed the concentration of NO and the enzymatic activity of NOS increased markedly at all stages of cirrhosis and iNOSmRNA was strongly expressed. Meanwhile, the portal-venous-pressure (PVP) and portal-venous-flow (PVF) were significantly increased. NO, NOS and iNOSmRNA were positively correlated to the degree of hepatic fibrosis. Tetrandrine significantly inhibited NO production and the expression of iNOSmRNA. Our results suggested that increased hepatic expression of NOSⅡ is one of the important factors causing cirrhosis and portal hypertension. Tetrandrine can significantly ameliorate cirrhosis and portal hypertension.
文摘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.
文摘The levels of plasma nitric oxide (NO), endothelin 1 (ET 1) and ALT in the patients with chronic hepatitis B and active cirrhosis and the correlation among them were observed and analyzed. NO 3 ˉ was restored by using cadmium column assay and NO 2 ˉ measured by heavy nitrogen assay. The primitive NO 3 ˉ and total restored NO 2 ˉ(NO 3 ˉ/ NO 2 ˉ) in plasma of the patients with chronic hepatitis and cirrhosis. Plasma ET 1 and ALT levels were determined by using radioimmunological assay and Lai's assay, respectively. Compared with normal control group, the plasma levels of NO 2 ˉ/NO 3 ˉ and ET 1 in the patients with chronic active hepatitis and active cirrhosis were significantly increased ( P <0.05-0.01). There was a positive correlation between NO and ALT, and ET 1 and ALT in the patients with chronic active hepatitis and active cirrhosis respectively. It was suggested that elevation of both NO and ET 1 levels were closely related with injury severity of liver function.
基金Supported by The Department of Biotechnology-Ramalingaswami Fellowship 5 years grant from the Government of India
文摘This review describes the recent developments in the pathobiology of endothelial dysfunction(ED) in the context of cirrhosis with portal hypertension and defines novel strategies and potential targets for therapy. ED has prognostic implications by predicting unfavourable early hepatic events and mortality in patients with portal hypertension and advanced liver diseases. EDcharacterised by an impaired bioactivity of nitric oxide(NO) within the hepatic circulation and is mainly due to decreased bioavailability of NO and accelerated degradation of NO with reactive oxygen species. Furthermore, elevated inflammatory markers also inhibit NO synthesis and causes ED in cirrhotic liver. Therefore, improvement of NO availability in the hepatic circulation can be beneficial for the improvement of endothelial dysfunction and associated portal hypertension in patients with cirrhosis. Furthermore, therapeutic agents that are identified in increasing NO bioavailability through improvement of hepatic endothelial nitric oxide synthase(e NOS) activity and reduction in hepatic asymmetric dimethylarginine, an endogenous modulator of e NOS and a key mediator of elevated intrahepatic vascular tone in cirrhosis would be interesting therapeutic approaches in patients with endothelial dysfunction and portal hypertension in advanced liver diseases.
文摘目的观察外源性脂联素对内皮素(ET)1诱导的肝星状细胞(HSC)-T6收缩的影响,探讨脂联素在此过程中的可能作用机制。方法应用胶原晶格法观察不同浓度(0.25、0.5μg/ml)脂联素及脂联素(0.5μg/ml)与左旋硝基精氨酸甲酯(LNAME)(5 mmol/L)共同作用下对ET-1诱导的HSC-T6细胞收缩的影响;分别采用实时荧光定量PCR、Western Blot检测脂联素(0.5μg/ml)作用后HSC-T6细胞中ET-1 mRNA及蛋白的表达,采用ELISA检测脂联素(0.5μg/ml)作用后HSC-T6细胞培养液中ET-1蛋白的表达;采用实时荧光定量PCR及Western Blot检测不同浓度(0.5、1、2μg/ml)脂联素与ET-1共同作用下HSC-T6细胞中诱导型一氧化氮合酶(i NOS)的mRNA及蛋白的表达,同时检测HSC-T6细胞中AMPK、p-AMPK、Akt、p-Akt蛋白的表达。计量资料多组间比较采用方差分析,进一步两两比较采用Dunnett法。结果 (1)胶原晶格实验显示,与空白对照组相比,ET-1组凝胶面积显著收缩[(24.8±7.3)%vs(71.9±4.1)%,P<0.01];脂联素(0.5μg/ml)处理后,明显抑制ET-1引起的收缩[(52.7±20.6)%vs(24.8±7.3)%,P<0.05];L-NAME(5 mmol/L)可以部分抵消脂联素的抑制作用(P>0.05)。(2)脂联素(0.5μg/ml)可以抑制HSC-T6细胞中ET-1 mRNA及蛋白的表达(P<0.05),同时可以抑制细胞上清液中ET-1的蛋白表达,在脂联素的基础上加入L-NAME后,脂联素的上述抑制作用均得到部分逆转。(3)HSC-T6细胞中有i NOS mRNA表达,加入ET-1后i NOS mRNA表达量明显下降(P<0.01),同时加入ET-1和脂联素作用后i NOS mRNA表达较ET-1组增加,且随着脂联素浓度升高i NOS mRNA表达量有逐渐升高的趋势,HSC-T6细胞中i NOS蛋白表达与mRNA表达趋势一致;ET-1处理24 h后HSC-T6细胞中p-AMPK表达水平明显减低,在此基础上加入脂联素后,p-AMPK表达水平明显上升,且随脂联素浓度的增加逐渐增加;ET-1处理24 h后HSC-T6细胞中p-Akt表达水平明显上升,在此基础上加入脂联素后,p-Akt的表达水平下降,且随脂联素浓度的增加逐渐降低。结论脂联素能够抑制ET-1诱导的HSC收缩,其机制可能是通过激活AMPK,增加NO的合成,减少ET-1的合成分泌,同时阻断Akt信号通路来实现的。脂联素抑制HSC的收缩作用可能是其抗肝纤维化的机制之一。
文摘目的:研究内源性一氧化氮(nitric oxide,NO)/一氧化氮合酶(nitricoxide synthase,NOS)体系及一氧化碳(carbonic oxide,CO)/血红素合酶(heme oxygenase,HO-1)体系对肝硬化大鼠门静脉压力的影响,探讨NO/NOS体系及CO/HO-1体系在大鼠肝硬化门静脉高压中的作用.方法:将SD大鼠随机分为4组:正常对照组(N C组)、正常对照+左旋硝基精氨酸甲酯(L-NAME)+锌原卟啉-Ⅸ(Znpp-Ⅸ)组(NC+LNAME+ZnPP-Ⅸ组)、肝硬化模型组(CIRM组)、肝硬化模型+左旋硝基精氨酸甲酯(L-NAME)+锌原卟啉-Ⅸ(Znpp-Ⅸ)组(CIRM+LNAME+ZnPP-Ⅸ组).均用插管法测定门静脉压力,用硝酸还原酶法测定血浆中NO含量,联二亚硫酸盐还原法测定血浆CO含量,运用蛋白免疫印迹技术(Western blot)测定肝组织中内皮细胞一氧化氮合酶(endothelial nitricoxide synthase,e N O S)、诱导型一氧化氮合酶(i n duc i b l e nitricoxide synthase,iNOS)及HO-1蛋白的表达情况.结果:与NC组相比,CIRM组血浆NO、CO含量明显升高(160.12μmol/L±4.18μmol/L,111.12μmol/L±2.26μmol/L vs 81.11μmol/L±2.91μmol/L,70.51μmol/L±3.10μmol/L,均P<0.01),门静脉压力明显升高(16.08 mmHg±1.16 mmHg vs 9.85 mmHg±1.10 mmHg,P<0.01),肝组织中iNOS及HO-1蛋白含量明显升高(165.69±1.17,155.79±1.29 vs 135.22±0.54,125.44±0.94,均P<0.01),但eNOS在肝组织的表达却明显降低(118.65±1.29 vs 160.77±2.12,P<0.01),而NC+L-NAME+ZnPP-Ⅸ组NO、CO含量则明显降低(52.06μmol/L±3.17μmol/L,52.51μmol/L±2.63μmol/L,均P<0.01),门静脉压力无统计学意义,肝组织中eNOS、iNOS及HO-1蛋白含量亦明显降低(130.83±1.57,120.81±1.47,111.03±1.45,均P<0.01);与CIRM组相比,CIRM+L-NAME+ZnPP-Ⅸ组血浆NO、CO含量明显降低(100.24μmol/L±3.80μmol/L,83.73μmol/L±1.78μmol/L,均P<0.01),门静脉压力明显降低(14.13 mmHg±0.56 mmHg,P<0.01),肝组织中eNOS、iNOS及HO-1蛋白含量明显降低(87.50±1.07,150.66±1.42,139.88±1.73,均P<0.01).结论:NO、CO作为新型气体信号分子,与肝硬化门静脉压力的变化密切相关,而NO、CO抑制剂的干预研究则进一步证明了内源性NO/NOS体系及CO/HO-1体系对肝硬化门静脉高压的形成具有重要的调节作用.
