Development of polyethylene glycol-conjugated poly-S-nitrosated serum albumin, a novel S-Nitrosothiol for prolonged delivery of nitric oxide in the blood circulation in vivo

S-Nitrosothiols are an interesting class of nitric oxide (NO) donors used for the treatment of circulation disorders. In this study, we developed a novel macromolecular NO donor in which 10 NO molecules were covalently bound to polyethylene glycol (PEG)-conjugated bovine serum albumin (BSA) through S-nitrosothiol linkages (PEG-poly SNO-BSA). Intermolecular disulfide linkages possibly formed during the introduction of thiol groups to BSA were prevented in PEG-poly SNO-BSA. Electron spin resonance study indicated that PEG-poly SNO-BSA does release the NO radical in the blood circulation in vivo. The area under the concentration-time curve of (111)In-PEG-poly N-succinimidyl S-acetylthioacetate (SATA)-BSA, the carrier part of PEG-poly SNO-BSA, was 1.7 times greater than that of (111)In-BSA after intravenous injection in mice. After intravenous injection in rats at an equivalent NO dose (3 micromol of NO per kilogram), the duration of reduction in the blood pressure was 2.3 to 3.7 times longer in PEG-poly SNO-BSA than in classic S-nitrosothiols such as S-nitroso-N-acetyl penicillamine, S-nitrosoglutathione, and NO-BSA. The release half-life of NO from PEG-poly SNO-BSA was 11 to 108 times longer than those of the classic S-nitrosothiols examined, and this slow release rate of NO would explain the sustained reduction in the blood pressure after intravenous injection of PEG-poly SNO-BSA in rats. No cross-tolerance between PEG-poly SNO-BSA and nitroglycerin was also observed. These findings indicate that the novel S-nitrosothiol PEG-poly SNO-BSA is a promising compound that exhibits unique characteristics of sustained release of NO in the blood circulation in vivo, which would be beneficial for the treatment of circulation disorders.     

Hepatocyte apoptosis is enhanced after ischemia/reperfusion in the steatotic liver

Liver steatosis is associated with organ dysfunction after hepatic resection and transplantation which may be caused by hepatic ischemia/reperfusion injury. The aim of the current study was to determine the precise mechanism leading to hepatocyte apoptosis after steatotic liver ischemia/reperfusion. Using a murine model of partial hepatic ischemia for 90 min, we examined the levels and pathway of apoptosis, and the peroxynitrite expression, serum alanine aminotransferase levels, and liver histology 1 and 4 h after reperfusion. In the steatotic liver, the peroxynitrite expression increased after ischemia/reperfusion. Significant hepatocyte apoptosis in the steatotic liver was seen after reperfusion, caused by upregulation of cleaved caspases 9 and 3, but not caspase 8. Serum alanine aminotransferase levels were elevated and histological examination revealed severe liver injury in the steatotic liver 4 h after reperfusion. In mice treated with aminoguanidine, ischemia/reperfusion-induced increases in serum alanine aminotransferase levels and apoptosis were significantly reduced in steatotic liver compared with mice treated with phosphate buffered saline. Survival of mice with steatotic livers significantly improved by treatment with aminoguanidine. Our data suggested that the steatotic liver is vulnerable to hepatic ischemia/reperfusion, leading to significant hepatocyte apoptosis by the mitochondrial permeability transition, and thereby resulting in organ dysfunction.     

异丙酚对兔肝缺血/再灌注损伤中一氧化氮和内皮素的干预

目的　探讨一氧化氮 (NO)和内皮素 (ET)在肝缺血 /再灌注损伤 (HIRI)中的作用及异丙酚对其的影响。方法　实验兔分为假手术对照组 (n =10 )、肝缺血 /再灌注组 (n =10 )及肝缺血 /再灌注 异丙酚治疗组 (n =10 ) ;分别检测缺血前、缺血 4 5min和再灌注 4 5min 3个时点的指标变化。用硝酸还原酶法检测血浆及肝组织一氧化氮代谢产物 (NOP)含量 ,放射免疫法测定ET水平 ,赖氏法测定谷丙转氨酶 (ALT)活性 ,并行肝组织电镜观察。结果　肝缺血 /再灌注期间 ,血浆NOP明显低于假手术对照组 ,而ET及ALT显著高于假手术对照组 ,尤以再灌注 4 5min变化显著 (P <0 0 5和P <0 0 1) ;肝组织NOP明显低于假手术对照组 ,而ET显著高于假手术对照组 (P <0 0 5和P <0 0 1) ;肝细胞形态学发生异常改变。异丙酚可逆转上述指标的异常变化。结论　缺血 /再灌注导致血管内皮功能紊乱 (即NO水平下降和ET水平升高 ) ,在HIRI发生发展中起介导作用 ;异丙酚通过保护肝窦内皮 ,提高机体内NO水平和降低机体内ET水平 ,从而减轻HIRI。     

异氟醚预处理对缺血/再灌注复合内毒素大鼠肝脏损伤的影响

目的 观察再灌注期腹腔注射内毒素脂多糖(LPS)对大鼠肝脏缺血/再灌注(I/R)损伤的影响以及异氟醚(ISO)预处理的干预作用.方法 将32只SD大鼠随机均分为4组:假手术(Sham)组、单纯肝脏I/R组、肝脏I/R复合LPS损伤(I/R+LPS)组及ISO预处理组.I/R+LPS组吸氧预处理后间隔0.5 h进行肝脏缺血1 h、再灌注4 h,再灌注开始时腹腔内注入LPS;ISO预处理组以ISO吸入预处理0.5 h,间隔0.5 h后进行I/R损伤操作,再灌注开始时腹腔内注入LPS.再灌注4 h处死各组动物,留取肝脏及血液标本;观察各组肝组织病理学改变,血清丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、肿瘤坏死因子-α(TNF-α)的变化以及肝组织TNF-α、髓过氧化物酶(MPO)活性的改变.结果 与Sham组比较,损伤各组血清ALT、AST、TNF-α及肝组织TNF-α、MPO活性均显著升高(P均＜0.01);与I/R组比较,I/R+LPS组肝脏损伤和炎症细胞因子反应明显较重(P＜0.05或P＜0.01)l与I/R+LPS组比较,ISO预处理组肝脏的病理损伤明显较轻,血清ALT、AST、TNF-α水平及肝组织MPO活性和促炎细胞因子TNF-α的表达水平均显著降低(P均＜0.05).结论 再灌注期复合LPS腹腔注射明显加重了肝脏的损伤和炎症细胞因子反应,ISO预处理可明显减轻复合损伤介导的炎症反应,保护肝脏.     

大黄对大鼠肠缺血再灌注所致肺损伤过程中内源性NO的影响

目的　在大鼠小肠缺血再灌注（ＩＩＲ） 模型上,研究内源性一氧化氮（ＮＯ）在ＩＩＲ所致肺损伤发病过程中的作用;观察大黄对ＮＯ的影响,探讨大黄防治肠源性肺损伤的机理。方法　ＳＤ大鼠随机分为肠缺血再灌注组、假手术组、大黄治疗组和安慰剂组监测平均动脉压（ＭＡＰ）。以１２５Ｉ标记小牛血清白蛋白（ＢＳＡ） 肺摄取指数作为评价肺毛细血管通透性的指标;采用镉还原柱层析和比色法分别测定各组动物不同时间血浆、肺及小肠组织内源性ＮＯ的含量。结果　大黄可明显改善ＩＩＲ导致的低血压状态;抑制血浆、肺及小肠组织内源性ＮＯ的释放（ Ｐ＜ ０－０５ 或Ｐ＜０－０１）;降低肺毛细血管通透性（ Ｐ＜ ０－０１） 。结论　早期应用大黄有助于防止大鼠肠源性肺损伤的发生,这种作用部分是通过抑制内源性ＮＯ大量释放实现的。     

参附注射液对兔肝脏缺血再灌注损伤保护作用的研究

目的研究参附注射液对兔肝脏缺血再灌注损伤的保护作用及其机理。方法 27只新西兰大白兔随机分为3组:对照组(A组)、缺血再灌注组(B组)、参附治疗组(C组)。分别在缺血前10min,缺血45min,再灌注45min取血检测肝功能、超氧化物歧化酶(SOD)、丙二醛(MDA)、肿瘤坏死因子(TNF-α)、白介素10(IL-10)、一氧化氮(NO)及肝组织标本行病理学观察。结果 C组与B组相比,再灌注45min肝酶指标、血浆MDA浓度、TNF-α浓度降低;血浆SOD活力、血浆IL-10浓度、血浆NO浓度升高,差异有统计学意义(t分别=-3.38～3.76,P均<0.05);病理检查提示C组肝脏变性坏死明显较B组减轻。结论参附注射液能增强兔血浆SOD活力,清除氧自由基,抑制脂质过氧化反应;抑制肝脏Kupffer细胞产生TNF-α,促进内源性IL-10的释放;促进肝脏合成释放NO,对兔肝脏缺血再灌注损伤有明显的保护作用。     

盐酸戊乙奎醚对大鼠肝脏缺血再灌注损伤的保护作用

【目的】探讨盐酸戊乙奎醚对大鼠肝脏缺血再灌注损伤的影响及作用机制。【方法】通过大鼠肝脏缺血再灌注损伤模型,检测大鼠血清丙氨酸氨基转移酶（ALT）和天冬氨基酸转移酶（AST）,肝组织匀浆丙二醛（MDA）的变化。观察光镜下肝脏病理形态改变。【结果】经盐酸戊乙奎醚处理的C组血清ALTAST和MDA的浓度明显低于B组（对照组）而高于A组（假手手术组）;C组光镜下肝脏病理形态改变较B组轻微。【结论】盐酸戊乙奎醚对大鼠肝脏缺血再灌注损伤有保护作用。     

Endothelial nitric oxide synthase protects the post-ischemic liver: potential interactions with superoxide.

Hepatic ischemia and reperfusion (I/R) continues to represent a significant cause of post-transplant liver failure. The roles that certain free radicals including nitric oxide (NO) and superoxide (O(2)(-)) play in this process are not well understood. The present study was designed to assess the role of endothelial cell nitric oxide synthase (eNOS) in I/R-induced liver injury in a murine model of hepatic I/R. Forty five minutes of partial (70%) hepatic ischemia followed by 3 and 6 h of reperfusion resulted in a significant increase in liver injury which occurred in the absence of neutrophil infiltration. eNOS-deficient mice displayed enhanced liver injury when compared to their wild type controls again in the absence of neutrophil infiltration. Interestingly, basal liver blood flow was significantly decreased in these mice when compared to controls though their blood flow during reperfusion was not significantly reduced from their wild type controls. Treatment of eNOS(-/-) mice with gadolinium chloride, a potent inhibitor of Kupffer cell function, but not superoxide dismutase, significantly reduced post-ischemic hepatocellular injury while either treatment protected the wild type mouse livers. Taken together, these data suggest that NO derived from eNOS may act to protect the post-ischemic liver possibly by suppression of Kupffer cell function and not by modulation of tissue perfusion. Further the data presented here would indicate that the protective effects conferred by SOD are related to its ability to increase the bioavailability of NO rather than by attenuating superoxide-dependent reactions. Data generated from these studies may prove useful in developing new drug therapies to treat the post-ischemic liver.     

Protective effect of S-nitrosylated alpha(1)-protease inhibitor on hepatic ischemia-reperfusion injury

S-Nitrosylated compounds (nitrosothiols; RS-NOs) function as nitric oxide (NO) reservoirs and preserve the antioxidant activities of NO. We found remarkable cytoprotection by an S-nitrosylated protease inhibitor from human plasma, S-nitroso-alpha(1)-protease inhibitor (S-NO-alpha(1)-PI) that possesses a completely nitrosylated SH group, in hepatic ischemia-reperfusion injuries in rats. Liver ischemia was induced in rats by occluding both the portal vein and hepatic artery for 30 min and was followed by reperfusion. S-NO-alpha(1)-PI and control compounds such as native alpha(1)-PI, an NO synthase (NOS) inhibitor, and standard RS-NOs were given via the portal vein just after reperfusion was initiated. Liver injury was evaluated by measuring the extracellular release of liver enzymes (aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase). Infiltration of neutrophils and induction of apoptosis and heme oxygenase-1 (HO-1) in the liver were also examined. Maximal liver injury occurred at 3 h after reperfusion and then decreased gradually. Not only did S-NO-alpha(1)-PI treatment (0.1 micromol; 5.3 mg/rat) greatly reduce elevation of liver enzymes in plasma, as well as neutrophil accumulation and apoptotic change in liver, it also improved the impaired hepatic blood flow as assessed by laser Doppler flowmetry and potentiated the induction of HO-1 in the liver. Although native alpha(1)-PI moderately reduced liver injury, low molecular weight RS-NOs such as S-nitrosoglutathione and S-nitroso-N-acetyl penicillamine produced no obvious protective effect. An NOS inhibitor exacerbated the hepatic ischemia-reperfusion injuries. These results suggest that S-NO-alpha(1)-PI exerts a potent cytoprotective effect on ischemia-reperfusion liver injury by maintaining tissue blood flow, inducing HO-1, and suppressing neutrophil-induced liver damage and apoptosis.     

P选择素单克隆抗体对大鼠肝缺血—再灌注损伤的治疗作用研究

目的：探讨Ｐ选择素单克隆抗体（单抗）对大鼠肝缺血再灌注损伤的保护作用。方法：在肝缺血再灌注大鼠模型上观察了细胞间粘附分子１和Ｐ选择素的变化，并用Ｐ选择素单抗对其进行阻断治疗。结果：缺血再灌注大鼠肝细胞发生水肿及空泡变性，血清天冬氨酸转氨酶和丙氨酸转氨酶水平升高；但再灌注前５分钟经静脉注射Ｐ选择素单抗，则肝组织与正常组相近，肝细胞未见空泡变性，血清酶水平明显减低；酶联免疫吸附试验发现，再灌注后血清ＩＣＡＭ１和血浆Ｐ选择素水平显著升高，经Ｐ选择素单抗处理的大鼠血ＩＣＡＭ１和Ｐ选择素明显下降。结论：ＩＣＡＭ１和Ｐ选择素与缺血再灌注损伤密切相关，Ｐ选择素单抗对肝缺血再灌注损伤具有保护作用。     

Inhaled NO accelerates restoration of liver function in adults following orthotopic liver transplantation

Ischemia/reperfusion (IR) injury in transplanted livers contributes to organ dysfunction and failure and is characterized in part by loss of NO bioavailability. Inhalation of NO is nontoxic and at high concentrations (80 ppm) inhibits IR injury in extrapulmonary tissues. In this prospective, blinded, placebo-controlled study, we evaluated the hypothesis that administration of inhaled NO (iNO; 80 ppm) to patients undergoing orthotopic liver transplantation inhibits hepatic IR injury, resulting in improved liver function. Patients were randomized to receive either placebo or iNO (n = 10 per group) during the operative period only. When results were adjusted for cold ischemia time and sex, iNO significantly decreased hospital length of stay, and evaluation of serum transaminases (alanine transaminase, aspartate aminotransferase) and coagulation times (prothrombin time, partial thromboplastin time) indicated that iNO improved the rate at which liver function was restored after transplantation. iNO did not significantly affect changes in inflammatory markers in liver tissue 1 hour after reperfusion but significantly lowered hepatocyte apoptosis. Evaluation of circulating NO metabolites indicated that the most likely candidate transducer of extrapulmonary effects of iNO was nitrite. In summary, this study supports the clinical use of iNO as an extrapulmonary therapeutic to improve organ function following transplantation.     

CD4(+) T-lymphocytes mediate ischemia/reperfusion-induced inflammatory responses in mouse liver.

The success of orthotopic liver transplantation is dependent on multiple factors including MHC tissue compatibility and ischemic/reperfusion injury. Ischemic/reperfusion (I/R) injury in the liver occurs in a biphasic pattern consisting of both acute phase (oxygen free radical mediated) and subacute phase (neutrophil-mediated) damage. Although numerous studies have given insights into the process of neutrophil recruitment after I/R injury to the liver, the exact mechanism that initiates this subacute response remains undefined. Using a T cell-deficient mouse model, we present data that suggests that T-lymphocytes are key mediators of subacute neutrophil inflammatory responses in the liver after ischemia and reperfusion. To this end, using a partial lobar liver ischemia model, we compared the extent of reperfusion injury between immune competent BALB/c and athymic nu/nu mice. Studies evaluating the extent of liver damage as measured by serum transaminases (GPT) demonstrate similar acute (3-6 h) post-I/R responses in these two mouse models. In contrast, the subacute phase (16-20 h) of liver injury, as measured by both serum GPT levels and percent hepatocellular necrosis, was dramatically reduced in T cell-deficient mice as compared with those with an intact immune system. This reduction in liver injury seen in nu/nu mice was associated with a 10-fold reduction in hepatic neutrophil infiltration. Adoptive transfer of T cell-enriched splenocytes from immune competent mice was capable of reconstituting the neutrophil-mediated subacute inflammatory response within T cell-deficient nu/nu mice. Furthermore, in vivo antibody depletion of CD4(+) T-lymphocytes in immune competent mice resulted in a reduction of subacute phase injury and inflammation as measured by serum GPT levels and neutrophil infiltration. In contrast, depletion of CD8(+) T-lymphocytes had no effect on these indexes of subacute inflammation. Kinetic analysis of T cell infiltration in the livers of BALB/c mice demonstrated a fivefold increase in the number of hepatic CD4(+) T-lymphocytes within the first hour of reperfusion with no significant change in the number of CD8(+) T-lymphocytes. In summary, these results implicate CD4(+) T-lymphocytes as key regulators in initiating I/R-induced inflammatory responses in the liver. Such findings have implications for therapy directed at the early events in this inflammatory cascade that may prove useful in liver transplantation.     

颈交感神经干离断对大鼠局灶性脑缺血再灌注损伤的影响

目的:采用颈交感干离断(TCST)模拟星状神经节阻滞,观察其对大鼠局灶性脑缺血再灌注损伤的影响。方法:将实验大鼠随机分成实验组、对照组和假手术组。采用血管内线栓法行大脑中动脉栓塞制作局灶性脑缺血再灌注模型,缺血2h再灌注24h。观察TCST对局灶性脑缺血大鼠神经行为学评分、脑梗死容积、缺血侧脑组织超氧化物歧化酶(SOD)活力、丙二醛(MDA)含量及一氧化氮(NO)水平的影响。结果:与对照组相比,实验组大鼠神经行为学评分和脑梗死容积明显降低(P<0.05),脑组织SOD活力增加,而MDA含量和NO水平显著降低(P<0.05)。结论:TCST对局灶性脑缺血再灌注损伤具有保护作用,其作用可能与其提高SOD活力、降低MDA含量和NO水平有关。     

17β-estradiol attenuates reduced-size hepatic ischemia/reperfusion injury by inhibition apoptosis via mitochondrial pathway in rats

The aim of this study was to investigate the effect of 17β-estradiol (E2) on hepatocyte apoptosis after reduced-size hepatic ischemia/reperfusion (I/R) injury and its mechanism. A rat model of reduced-size hepatic I/R injury was established. Sprague-Dawley rats were randomly allocated into sham, I/R, and E2 + I/R group. 17β-Estradiol (4 mg/kg) or the vehicle was administered i.p. 1 h before ischemia and immediately after operation. For each group, 10 rats were used to investigate the survival during a week after reperfusion. Blood samples and liver tissues were obtained in the remaining animals after 3, 6, 12, and 24 h of reperfusion to assess serum aspartate aminotransferase and alanine aminotransferase levels, liver tissue malondialdehyde concentration, superoxide dismutase activity, and histopathologic changes. Apoptosis ratio; expression of cytochrome c, Bcl-2, and Bax proteins; and enzymatic activities of caspase 9 and caspase 3 were performed in the samples at 12 h after reperfusion. The serum aspartate aminotransferase and alanine aminotransferase levels and tissue malondialdehyde concentration were increased in the I/R group, whereas the increase was significantly reduced by E2. The superoxide dismutase activity, depressed by I/R injury, was elevated back to normal levels by treatment with E2. Severe hepatic damage was observed by light microscopy in the I/R group, whereas administration of E2 resulted in tissue and cellular preservation. Furthermore, E2 inhibited hepatocellular apoptosis by upregulating the ratio of Bcl-2 and Bax expression, reduced cytosolic cytochrome c level, and decreased caspase 9 and caspase 3 activities. The 7-day survival rate was significantly higher in the E2 + I/R group than in the I/R group. These results indicated that E2 protects liver tissues from reduced-size hepatic I/R injury by suppressing mitochondrial apoptotic pathways.     

Gabexate mesilate, a synthetic protease inhibitor, reduces ischemia/reperfusion injury of rat liver by inhibiting leukocyte activation.

OBJECTIVE: To investigate whether gabexate mesilate, a synthetic protease inhibitor with anticoagulant properties, prevents hepatic damage by inhibiting leukocyte activation, we examined its effect on ischemia/reperfusion injury of rat liver in which activated leukocytes play a critical role. DESIGN: Prospective, randomized, controlled study. SETTING: Research laboratory at a university medical center. SUBJECTS: Male Wistar rats weighing 220 to 280 g. INTERVENTIONS: Hepatic damage was evaluated by changes in bile flow and serum transaminase concentrations after ischemia/ reperfusion. Rats received continuous intravenous infusions of gabexate mesilate (10 mg/kg/hr) or intravenous administration of an inactive derivative of activated factor X (Xa), a selective inhibitor of thrombin generation (3 mg/kg), immediately before the induction of ischemia in the median and left lobes of the liver. To determine whether gabexate mesilate inhibits leukocyte activation, we examined the effects of gabexate mesilate on hepatic concentrations of tumor necrosis factor-alpha and rat interleukin-8 and on hepatic myeloperoxidase activity after ischemia/reperfusion. MEASUREMENTS AND MAIN RESULTS: Hepatic dysfunction, observed after 60 mins of ischemia/reperfusion, showed a reduction in bile flow. The ischemia/reperfusion-induced decrease in bile flow was prevented by administration of gabexate mesilate. Serum transaminase concentrations increased after hepatic ischemia/reperfusion, peaking 12 hrs after reperfusion. Gabexate mesilate significantly inhibited the ischemia/reperfusion-induced increase in serum transaminase levels seen 12 hrs after reperfusion. Although an inactive derivative of factor Xa inhibited the increases in serum levels of fibrin and fibrinogen degradation products 6 hrs after reperfusion, it did not prevent ischemia/ reperfusion-induced liver injury. Hepatic levels of tumor necrosis factor-alpha, rat interleukin-8, and myeloperoxidase were significantly increased after ischemia/reperfusion. These increases were significantly inhibited by gabexate mesilate but unaffected by an inactive derivative of factor Xa. CONCLUSION: Gabexate mesilate reduced ischemia/reperfusion-induced hepatic injury not by inhibiting coagulation, but by inhibiting leukocyte activation.     

Neutrophil elastase inhibitor (ONO-5046) attenuates reperfusion-induced hepatic microcirculatory derangement, energy depletion and lipid peroxidation in rats

Microcirculatory derangement, energy depletion, and lipid peroxidation are associated with the development of ischemia-reperfusion injury in the liver. This study investigated the effects of a neutrophil elastase inhibitor (ONO-5046) on hepatic ischemia-reperfusion injury. Adult, male Sprague-Dawley rats were divided into four treatment groups: 1) sham-operated control (laparotomy only, no ischemia) and saline injection (1 mL/kg), n = 6; 2) ischemia control (1-h ischemia, 2-h reperfusion) and saline injection (1 mL/kg), n = 6; 3) intravenous injection with ONO-5046 at a dose of 1 mg/kg 5 min before ischemia and immediately after reperfusion plus 1-h ischemia and 2-h reperfusion, n = 6; and 4) intravenous injection with ONO-5046 at a dose of 10 mg/kg 5 min before ischemia and immediately after reperfusion plus 1-h ischemia and 2-h reperfusion, n = 6. A laser-Doppler flowmeter and in vivo microscopy were used to investigate hepatic microcirculation. Tissue malondialdehyde (MDA) and adenosine triphosphate (ATP) levels were determined at the end of the experiment. RESULTS: Compared with ischemia alone, ONO-5046 significantly reduced the extent of microcirculatory and hemodynamic derangement after ischemia-reperfusion. ONO-5046 at both doses significantly attenuated decreases in mean arterial pressure. ONO-5046 lessened adherent leukocyte count and improved flow velocity in the sinusoids and postsinusoidal venules. ONO-5046 at the dose of 10m/kg reduced MDA (1.97 +/- 0.54 micromol/g protein vs. 3.58 +/- 1.21 micromol/g protein in the ischemia and reperfusion group) and increased ATP levels (2.62 +/- 0.19 micromol/g wet wt vs. 0.57 +/- 0.37 pmol/g wet wt in the ischemia and reperfusion group), whereas ONO-5046 at a smaller dose (1 mg/kg) had lesser but significant effects on MDA and ATP alterations. This study demonstrates that treatment with ONO-5046, a neutrophil elastase inhibitor, can ameliorate ischemia-reperfusion injury of the rat liver.     

高渗盐水对缺血/再灌注损伤肝脏血红素加氧酶-1表达的影响

目的 探讨高渗盐水预处理对肝脏缺血／再灌注损伤的保护作用及其机制。方法 25只SD大鼠随机分为假手术组、血红素加氧酶-1（HO-1）抑制剂锌原卟啉（ZnPP）组、缺血／ig灌注组、高渗盐水预处理组及ZnPP干预组，每组5只。建立大鼠局部肝脏缺血／再灌注损伤模型，于缺血／再灌注后6h测定血清丙氨酸转氨酶（ALT）活性、肿瘤坏死因子-α（TNF-α）含量、肝组织髓过氧化物酶（MPO）活性及肝组织内皮素1（ET1）含量；采用逆转录-聚合酶链反应（RTPCR）和蛋白质免疫印迹法（Westernblot）检测肝组织HO-1mRNA和蛋白表达；光镜和电镜下观察肝脏病理学改变及肝窦情况。观察使用ZnPP后，高渗盐水预处理对肝脏缺血／再灌注损伤的保护作用。结果 肝脏缺血／再灌注后血清ALT活性、TNF-α含量及肝组织MPO活性、ET-1含量均明显升高（P均d0．01），HO-1mRNA和蛋白表达明显增强。高渗盐水预处理明显增强缺血／再灌注后肝脏HO-1mRNA及蛋白表达，降低血清ALT、TNF-α水平及肝组织MPO活性和ET-1含量，肝脏微循环明显改善；使用ZnPP以后，高渗盐水预处理的保护作用消失。结论 高渗盐水预处理通过增强HO-1表达，对肝脏缺血／再灌注损伤产生保护作用。     

红花注射液对实验性脑缺血再灌注损伤中一氧化氮和内皮素的影响

目的　探讨一氧化氮 (NO)和内皮素 (ET)在脑缺血再灌注损伤 (CIRI)中的作用及红花注射液对其的影响。方法　实验家兔分为假手术对照组 (n =8)、脑缺血再灌注组 (n =8)及脑缺血再灌注 +红花组 (n =8) ;分别检测缺血前、缺血 3 0min及再灌注 3 0、60、12 0min 5个时相点血浆NO代谢产物 (NOP)的含量、ET水平的变化 ,同时测定再灌注 12 0min脑组织NOP、ET的浓度 ,并行脑组织电镜观察。结果　脑缺血再灌注 3 0min血浆NOP明显低于假手术对照组 (P <0 0 5 ) ;脑缺血再灌注3 0、60、12 0min血浆ET显著高于假手术对照组 ,尤以再灌注 12 0min变化显著 (P <0 0 1) ;脑组织NOP明显低于、ET显著高于假手术对照组 (P <0 0 5和P <0 0 1) ;脑组织超微结构发生异常改变。红花可逆转上述指标的异常变化。结论　缺血再灌注导致血管内皮功能紊乱 (即NO水平下降和ET水平升高 ) ,在CIRI发生发展中起介导作用 ;红花注射液通过保护血管内皮 ,提高机体内NO水平和降低机体内ET水平 ,从而减轻CIRI。     

加贝酯对大鼠肝脏缺血再灌注损伤细胞因子的作用和影响

【目的】观察细胞因子在大鼠肝脏缺血再灌注损伤中的变化和加贝酯（GM）对其的作用、影响及可能的机制。【方法】采用Pringle＇s法建立大鼠肝脏缺血再灌注模型,将40只SD大鼠随机分成四组,每组10只：A组（手术对照组）、B组（缺血再灌注组）、C组（加贝酯处理组）、D组（盐水对照组）。光镜观察肝脏病理组织学变化,测定血清中天冬氨酸氨基转移酶（AST）、丙氨酸氨基转移酶（ALT）、肿瘤坏死因子－α（TNF-α）及白介素6（IL－6）的含量。【结果】肝脏缺血再灌注损伤时,AST、ALT、TNF-α、IL－6含量显著地升高,并出现明显的病理学改变;而加贝酯处理后上述改变均明显减轻,其差异有显著性（P〈0．05）。【结论】肝缺血再灌注损伤后,产生大量的炎性细胞因子,而加贝酯通过其细胞保护作用、减少炎性细胞因子的产生及减轻炎症反应而产生肝保护作用。     

左旋精氨酸对兔肺缺血/再灌注损伤时细胞凋亡的影响

目的观察左旋精氨酸对免肺缺血／再灌注损伤中细胞凋亡的影响。方法复制单侧免肺缺血／再灌注损伤模型．随机分为三组：对照组（C组）、缺血／再灌注组（I／R组）和左旋精氨酸组（L—Arg组），每组10只。再灌注180min时取肺组织，观察超氧化物歧化酶（SOD）活性、丙二醛（MDA）浓度、一氧化氮（NO）含量、肺湿干比（W／D）、肺泡损伤数定量评价指标（IQA）及肺组织细胞凋亡指数（At）。结果I／R组与C组比较，SOD活性、NO含量明显降低（P〈0．01），MDA、W／D、IQA、AI明显升高（P〈0．01），L—Arg组与I／R组相比较，SOD活性、NO含量均明显升高（P〈0．01），MDA、W／D、IQA、AI不同程度降低（P〈0．05）。结论左旋精氨酸可通过提高体内NO水平、降低氧自由基水平、减轻脂质过氧化反应，抑制肺组织细胞凋亡，从而减轻肺损伤。