Prevention of neutrophil-mediated hepatic ischemia/reperfusion injury by superoxide dismutase and catalase derivatives

Our previous study demonstrated that the combination of mannosylated superoxide dismutase (Man-SOD) and succinylated catalase (Suc-CAT), both of which are designed to be targeted to liver nonparenchymal cells, is a promising approach to prevent the initial phase of hepatic ischemia/reperfusion injury induced by occlusion of the portal vein for 30 min followed by a 1-h reperfusion in mice. In this study, the preventive effects of these agents were examined on late-phase injury mediated by infiltrating neutrophils, a more severe condition than the initial one. Administration of Suc-CAT alone or with Man-SOD to mice undergoing hepatic ischemia/reperfusion significantly suppressed the expression of intercellular adhesion molecule-1 along the hepatic sinusoid and prevented neutrophil infiltration in the liver. Man-SOD and Suc-CAT also prevented the increase in plasma glutamic pyruvic transaminase and glutamic oxaloacetic transaminase activities after reperfusion lasting 3 and 6 h. Histological evaluation of liver tissues confirmed the efficacy of this treatment, suggesting that these SOD and catalase derivatives have the ability to suppress neutrophil-induced hepatic injury. These results demonstrate that targeted delivery of antioxidant enzymes to liver nonparenchymal cells is a promising approach to reducing the reactive oxygen species produced by Kupffer cells and neutrophils infiltrating into the tissue. Since Suc-CAT is partially taken up by hepatocytes via a catalase-specific uptake mechanism, such a fraction could also be involved in its preventive effect against the injury.     

Role of tumor necrosis factor-alpha in the pathophysiologic alterations after hepatic ischemia/reperfusion injury in the rat.

Cytokines are recognized as critical early mediators of organ injury. We attempted to determine whether or not severe hepatic ischemia/reperfusion injury results in tumor necrosis factor-alpha (TNF-alpha) release with subsequent local and systemic tissue injury. After 90 min of lobar hepatic ischemia, TNF was measurable during the reperfusion period in the plasma of all 14 experimental animals, with levels peaking between 9 and 352 pg/ml. Endotoxin was undetectable in the plasma of these animals. Pulmonary injury, as evidenced by a neutrophilic infiltrate, edema and intra-alveolar hemorrhage developed after hepatic reperfusion. The neutrophilic infiltrate was quantitated using a myeloperoxidase (MPO) assay; this demonstrated a significant increase in MPO after only 1 h of reperfusion. Anti-TNF antiserum pretreatment significantly reduced the pulmonary MPO after hepatic reperfusion. After a 12-h reperfusion period, there was histologic evidence of intra-alveolar hemorrhage and pulmonary edema. Morphometric assessment showed that pretreatment with anti-TNF antiserum was able to completely inhibit the development of pulmonary edema. Liver injury was quantitated by measuring serum glutamic pyruvic transaminase which showed peaks at 3 and 24 h. Anti-TNF antiserum pretreatment was able to significantly reduce both of these peak elevations. These data show that hepatic ischemia/reperfusion results in TNF production, and that this TNF is intimately associated with pulmonary and hepatic injury.     

Liver function tests in patients with computed tomography demonstrated hepatic metastases

One hundred patients with computed tomographic (CT) evidence of liver metastases (and confirmation by biopsy or progression of disease) had serum levels of alkaline phosphatase, serum glutamic oxaloacetic transaminase, and serum glutamic pyruvic transaminase measured within two weeks of scanning. All three enzymes were within the normal range in 33% of patients. Even with advanced involvement (defined as three or more metastatic lesions over 3 cm in diameter), 20% of patients had normal levels of all three liver enzymes. Although liver function tests (LFTs) (enzyme levels) are inexpensive and simple to perform, they failed to detect a significant number of patients with liver metastases.     

Normothermic liver ischemia in rats: xanthine oxidase is not the main source of oxygen free radicals

We studied the effect of allopurinol (ALL) on the activity of xanthine dehydrogenase (XDH), xanthine oxidase (XOX), superoxide dismutase (SOD), and catalase (CAT) in rat liver during ischemia followed by 60 min of reperfusion. We induced 60-min ischemia in the median and left lobes by clamping the hepatic artery and portal branches. The percentage XOX relative to total oxidase activity increased significantly in the control group, from 10% during the stabilization period to 18% after 60 min of reperfusion. The XDH activity decreased during reperfusion. Activity of both XDH and XOX was almost completely blocked by ALL. The activity of SOD and CAT did not differ significantly between the ALL group and controls after 60 min of reperfusion. ALL treatment did not affect liver injury parameters, as concentrations of lactate dehydrogenase (LDH) and alanine transferase (ALT) increased in plasma after ischemia, both in controls and in the ALL-treated group. We concluded that ischemia promotes conversion of XDH to XOX during reperfusion. XOX may not be the main source of free radical production, since intracellular scavengers (SOD and CAT) did not differ significantly between controls and the ALL-treated group, despite the fact that ALL blocked XOX activity completely.     

Effects of polyethylene glycol-linked superoxide dismutase and catalase during in vivo lung ischemia and reperfusion

We have previously demonstrated that reperfusion of a rabbit lung following 24 hours of in vivo pulmonary artery occlusion results in bilateral lung edema and lung inflammation and in systemic leukopenia. We tested whether this in vivo ischemia/reperfusion lung injury in the rabbit could be prevented by the administration of superoxide dismutase (SOD) and catalase (CAT). Polyethylene glycol-linked SOD (PEG-SOD) and CAT (PEG-CAT) were administered to five rabbits, PEG-SOD alone to four rabbits, and neither to nine untreated control rabbits, and the left pulmonary artery was then occluded with a microvascular clamp. Enzyme activity measured at the time of reperfusion 24 hours later demonstrated plasma CAT activity of 1,127 ± 601 U/mL for SOD/CAT-treated rabbits versus 193 ± 25 U / mL for untreated rabbits (P < .05) and SOD activity of 97 ± 25 U/mLfor SOD-treated rabbits versus no measurable activity in untreated rabbits. Following 4 hours of reperfusion, wet to dry ratios were 6.15 ± 0.27 for the reperfused left lungs and 5.55 ± 0.20 for the right lungs. Analysis of variance demonstrated a significant effect of reperfusion on left versus right wet to dry ratios (P < .05) but no effect of enzyme treatment. Lung sections scored by a blinded observer for histologic evidence of lung injury similarly showed a left-to-right difference but no difference between treated and untreated animals in degree of injury to the reperfused left lung. However, the contralateral lung was relatively less injured in treated rabbits. The two groups also differed in that an immediate leukopenia developed following reperfusion in the untreated and PEG-SOD-treated rabbits but not in the rabbits treated with both PEG-SOD and PEG-CAT. We conclude that SOD and CAT prevent the systemic leukopenia that accompanies pulmonary artery reperfusion, but do not prevent the injury to the reperfused lung. The sparing effect on the contralateral lung suggests that the mechanism of injury for that lung differs from the mechanism of injury to the occluded lung.     

严重烧伤后早期营养支持途径对肝功能的影响

目的考察严重烧伤早期营养支持途径对机体肝功能的影响。方法37例烧伤病人随机分为早期肠道营养组和肠外营养组，观察不同途径的营养支持两周后肝功指标的变化情况。结果严重烧伤后血清血清谷草转氨酶、碱性磷酸酶、乳酸脱氢酶均明显高于正常值，不同途径的营养支持两周，血清谷草转氨酶及血清碱性磷酶活性在伤后14d肠外营养组均明显高于肠道营养组(P＜0.05)。结论严重烧伤后病人出现不同程度的肝脏功能受损，肠外营养与肝脏功能的受损有关。     

Effect of chemically modified tetracycline on transforming growth factor-beta1 and caspase-3 activation in liver of septic rats

OBJECTIVES: We have previously demonstrated that hepatic matrixmetalloproteinase (MMP)-9 and gelatinase activity increased significantly after sepsis, and pretreatment with chemically modified tetracycline (CMT-3) inhibited these expressions and improved survivability. It has been established that MMP-9 release from hepatic nonparenchymal cells activates transforming growth factor (TGF)-beta1, which in turn catalyzes the conversion of procaspase-8 into active caspase-8. Caspase-8 activates caspase-3, which in turn degrades fibronectin and focal adhesion kinase and leads to disruption of hepatic architecture and integrity. We have been interested in investigating the role of posttreatment with CMT-3 on hepatic MMP-9, TGF-beta1, and caspase-3 activity following sepsis. DESIGN: Laboratory experiment. SETTING: University laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: In this study, sepsis was induced in rats by cecal ligation and puncture (CLP), and 2 hrs later, half of the rats received CMT-3 (25 mg/kg), whereas the other half received vehicle by gavage. Twenty-four and 48 hrs after sepsis induction, blood and liver samples were collected. MEASUREMENTS AND MAIN RESULTS: Plasma glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT) levels were determined by enzymatic method, and the activation states of hepatic MMP-9, MMP-2, tissue inhibitor of metalloproteinase (TIMP)-1, TGF-beta1, and caspase-3 were determined by Western immunoblotting. Plasma GOT, GPT, and hepatic MMP-9 activity increased 2.5-fold, and TFG-beta1 and caspase-3 activity increased 1.5- to 2-fold at 24 hrs and 48 hrs post-CLP; CMT-3 treatment blocked these increases. Furthermore, CMT-3 treatment also led to increased TIMP-1 level, an in vivo inhibitor of MMP-9. MMP-2 level was unaffected by CLP. The 24-hr and 48-hr mortality rates for CLP rats were 29% and 50%, whereas posttreatment with CMT-3 resulted in 0% mortality. CONCLUSIONS: Our results are consistent with an MMP-9-induced caspase-3 activation in response to CLP. CMT-3 posttreatment increased TIMP-1 level and thereby inhibited MMP-9, which in turn decreased TGF-beta1 and caspase-3 signaling pathways and improved survivability in septic rats.     

Primary cytomegalovirus infection and liver involvement in early infancy.

Virus isolation and determination of serum transaminase activity in 237 patients under one year of age were undertaken to clarify the etiologic significance of primary infection with cytomegalovirus (CMV) in infancy. The rates of virus recovery from infants with liver involvement were 37% (29/78) and 42% (28/66), as determined by serum glutamic oxaloacetic (S-GOT) and serum glutamic pyruvic (S-GPT) transaminase values. In contrast, CMV was recovered from 14% (18/127) and 13% (18/141) of infants with normal S-GOT and S-GPT values. The differences in the rates of virus recovery between both groups were more pronounced in infants under three months of age, that is, 5 to 7 times higher rates in infants with liver involvement. Correlation between complement-fixing antibody and liver involvement, however, was not significant, probably because of the influence by maternal antibody. Majority of infants infected with CMV are postulated to involve liver during immediate months after onset of virus excretion.     

异丙酚对围术期缺血-再灌注损伤肝脏的保护作用

目的　探讨异丙酚对围术期肝脏缺血再灌注损伤 (HIRI)的防治作用及其机制。方法　选择 18例肝癌手术患者 ,观察肝门阻断前后及再灌注后血中超氧化物歧化酶 (SOD)活性、黄嘌呤氧化酶 (XO)活性、脂质过氧化物 (L PO)浓度和丙氨酸转氨酶 (AL T)值 ;对再灌注 2 5 min时的肝组织进行电镜下肝细胞形态学变化的观察 ,以评价异丙酚对上述指标的影响。结果　 HIRI期间 ,SOD活性显著下降 (P<0 .0 1) ,XO活性、L PO浓度及 AL T值明显升高 (P均 <0 .0 1) ;肝组织超微结构发生异常改变。使用异丙酚后 ,上述指标的异常变化显著减轻 ,其差异有显著意义 (P<0 .0 5或 P<0 .0 1)。结论　异丙酚可通过降低氧自由基水平、拮抗脂质过氧化反应 ,对围术期 HIRI起积极的防治作用。     

Brain cooling causes attenuation of cerebral oxidative stress, systemic inflammation, activated coagulation, and tissue ischemia/injury during heatstroke

The purpose of the present study was to assess the therapeutic effect of hypothermic retrograde jugular vein flush (HRJVF) on heatstroke. HRJVF was accomplished by infusion of 4 degrees C isotonic sodium chloride solution via the external jugular vein (1.7 mL/100 g of body weight over 5 min). Immediately after the onset of heatstroke, anesthetized rats were divided into 2 major groups and given the following: 36 degrees C or 4 degrees C isotonic sodium chloride solution, i.v. They were exposed to ambient temperature of 43 degrees C to induce heatstroke. Another group of rats was exposed to room temperature (24 degrees C) and used as normothermic controls. When the 36 degrees C saline-treated rats underwent heat exposure, their survival time values were found to be 23 to 28 min. Immediately after the onset of heatstroke, resuscitation with an i.v. dose of 4 degrees C saline significantly improved survival during heatstroke (208-252 min). All heat-stressed animals displayed systemic inflammation and activated coagulation, evidenced by increased tumor necrosis factor alpha, prothrombin time, activated partial thromboplastin time, and d-dimer, and decreased platelet count and protein C. Biochemical markers evidenced cellular ischemia and injury/dysfunction: plasma levels of blood urea nitrogen, creatinine, glutamic oxaloacetic transaminase, glutamic pyruvic transaminase, and alkaline phosphatase; and striatal levels of glycerol, glutamate, and lactate/pyruvate; dihydroxy benzoic acid, lipid peroxidation, oxidized-form glutathione reduced-form glutathione, dopamine, and serotonin were all elevated during heatstroke. Core and brain temperatures and intracranial pressure were also increased during heatstroke. In contrast, the values of mean arterial pressure, cerebral perfusion pressure, and striatal levels of local blood flow, partial pressure of oxygen, superoxide dismutase, catalase, glutathione peroxidase, and glutathions reductase activities were all significantly lower during heatstroke. The circulatory dysfunction, systemic inflammation, hypercoagulable state, and cerebral oxidative stress, ischemia, and damage during heatstroke were all significantly suppressed by HRJVF. These findings demonstrate that brain cooling caused by HRJVF therapy may resuscitate persons who had a stroke by attenuating cerebral oxidative stress, systemic inflammation, activated coagulation, and tissue ischemia/injury during heatstroke.     

Pharmacokinetic analysis of in vivo disposition of succinylated proteins targeted to liver nonparenchymal cells via scavenger receptors: importance of molecular size and negative charge density for in vivo recognition by receptors

In vivo disposition characteristics of succinylated (Suc-) proteins were studied after intravenous injection in mice in relation to their molecular characteristics as negatively charged macromolecules. Recombinant superoxide dismutase (SOD; molecular mass, 32 kDa), bovine serum albumin (BSA; molecular mass, 67 kDa), and bovine IgG (molecular mass, 150 kDa) were used to produce succinylated derivatives with different degrees of modification. (111)In-labeled Suc-SODs were rapidly excreted into the urine with no significant hepatic uptake. In contrast, (111)In-Suc-BSA and Suc-IgG were significantly taken up by liver nonparenchymal cells via scavenger receptors (SRs) according to the degree of succinylation and the dose injected. Interestingly, highly succinylated BSAs exhibited significant accumulation in the kidney at higher doses when the hepatic uptake was saturated. Pharmacokinetic analysis demonstrated that the hepatic uptake of succinylated proteins depended on the molecular size and the estimated surface density of succinylated amino residues. Further analysis based on a physiological pharmacokinetic model, involving a saturable process with Michaelis-Menten kinetics, revealed that the surface density of negative charges was correlated with the affinity of larger succinylated proteins for the hepatic SRs. Thus, the present study has provided useful basic information for a therapeutic strategy and the molecular design of succinylated proteins for use as drug carriers and therapeutic agents per se for SR-mediated targeting in vivo.     

Iron status and liver function in healthy adults: a multiracial pilot study

We tested 157 apparently healthy, urban adults (78 black, 40 nonblack, 39 race not designated), and found that 7.7% of the entire group had high plasma ferritin levels (6.4%) or transferrin saturation levels (1.3%). Overall, men had significantly higher mean plasma ferritin, serum glutamic pyruvic transaminase, and total serum bilirubin values than women. In this study 17.6% of black men had high plasma ferritin levels and another 11.8% had high transferrin saturation levels. Their mean serum iron and transferrin saturation levels were significantly higher than those of nonblack men. Black men had significantly higher mean serum iron, transferrin saturation, plasma ferritin, serum glutamic pyruvic transaminase, and total serum bilirubin levels than black women. The same tests were not significantly different when black and nonblack women were compared. Likely causes of the laboratory abnormalities are occult inflammation and occult liver disease, but a primary disorder of iron metabolism is also possible.     

Inhibition of Matrix Metalloproteinase on Hepatic Transforming Growth Factor β1 and Caspase-3 Activation in Hemorrhage

Objectives: Hemorrhage initiates an inflammatory response that induces the systemic release of cytokines and sequestration of polymorphonuclear neutrophils. Sequestered polymorphonuclear neutrophils release proteases, including matrix metalloproteinases (MMPs) that degrade elements of the extracellular matrix, contributing to the morbidity and mortality seen from hemorrhage. Activation of MMPs may be associated with changes in transforming growth factor β1 (TGF‐β1) and caspase‐3 signaling pathways. In this study, the authors examined hemorrhage‐induced changes in the expression of rat hepatic MMP‐9, tissue inhibitor of metalloproteinase‐1 (TIMP‐l), TGF‐β1, and caspase‐3 activities in the presence and absence of the MMP inhibitor hydroxamate. Methods: Hemorrhagic shock was induced in fasted, anesthetized, and cannulated rats by rapid phlebotomy to a mean arterial pressure level of 40 mm Hg, maintained for 90 minutes by withdrawal and infusion of blood, followed by a resuscitation period of lactated Ringer's infusion. Rats received either hydroxamate (25 mg/kg) or vehicle by gavage before hemorrhage. Twenty‐four hours after resuscitation, plasma and liver samples were collected. Liver MMP‐9, TGF‐β1, and caspase‐3 levels were quantified by Western immunoblotting. Plasma glutamic oxaloacetic transaminase (GOT) and plasma glutamic pyruvic transaminase (GPT) were determined enzymatically. Results: Plasma GOT, plasma GPT, and liver MMP‐9, TGF‐β1, and caspase‐3 levels were all significantly elevated at 24 hours postresuscitation when compared with the control values. Hepatic TIMP‐1, an in vivo inhibitor of MMP‐9, was unaltered at 24 hours. Hydroxamate treatment reduced GOT, GPT, MMP‐9, TGF‐β1, and caspase‐3 levels at 24 hours. The mortality of hemorrhaged untreated rats was 29% after 24 hours, and pretreatment with hydroxamate reduced mortality to 0%. Conclusions: These results indicate the beneficial effects of MMP inhibitor in preventing an increase in GOT, GPT, MMP‐9, TGF‐β1, and caspase‐3 activity with the potential for improvement of hepatic injury due to hemorrhage.     

Prevention of ischemia/reperfusion injury by hepatic targeting of nitric oxide in mice

Macromolecular nitric oxide (NO) donors possessing the ability to target a specific type of liver cells were developed for delivering NO to the liver. Six NO molecules were covalently bound to mannosylated (Man) or galactosylated (Gal) bovine serum albumin (BSA) through an S-nitrosothiol linkage to obtain Man-poly SNO-BSA and Gal-poly SNO-BSA, respectively. The carrier parts of Man-poly SNO-BSA and Gal-poly SNO-BSA predominantly accumulated in the liver after intravenous injection in mice. In an ischemia/reperfusion injury mouse model, in which hepatic injury was induced by occluding the portal vein for 15 min followed by a 6 h reperfusion, the elevation of plasma alanine aminotransferase and aspartate aminotransferase levels was significantly inhibited by a bolus intravenous injection of Man-poly SNO-BSA or Gal-poly SNO-BSA, just before the start of reperfusion. In marked contrast, S-nitroso-N-acetyl penicillamine and NO-conjugated BSA, two classical S-nitrosothiols, had no statistically significant effects on the serum levels of the markers. The released NO in mouse liver was detected by electron spin resonance spectrometry only in the liver of mice receiving Man-poly SNO-BSA or Gal-poly-SNO-BSA. These findings indicate that Man-poly SNO-BSA and Gal-poly SNO-BSA are promising compounds for preventing hepatic ischemia/reperfusion injury by delivering pharmacologically active NO to the liver.     

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.     

重症急性胰腺炎预后的早期相关因素分析

目的探讨重症急性胰腺炎(severe acute pancreatitis,SAP)患者入院24 h内与预后的相关因素.方法 对193例SAP患者临床资料作回顾性分析.按预后分为死亡组和存活组,先以单因素分析筛选有统计学意义的影响因素,再通过Logistic回归分析筛选与预后有关的影响因素.结果 SAP死亡组患者年龄、血钙、阴离子间隙、血浆总蛋白、血清白蛋白、肌酐、尿素氮与存活组患者比较差异有统计学意义(P<0.05),SAP死亡组患者性别、病因、红细胞比积、白细胞计数、血小板计数、氧分压、谷草转氨酶、谷丙转氨酶、乳酸脱氢酶与存活组患者比较差异无统计学意义(P>0.05).Logistic回归分析显示早期血肌酐、血清总蛋白浓度与SAP预后存在相关性(P<0.05).结论 入院24h内的血肌酐、血清总蛋白浓度是影响SAP预后的早期因素.     

大鼠烫伤后早期肝脏的变化及其机制

目的：观察大鼠烫伤后早期肝功能变化及肝窦内皮细胞（ＳＥＣ）在其中的作用。方法：制备大鼠烫伤模型，检测伤后２、１２、２４小时血清丙氨酸转氨酶、胆红素、红细胞压积、丙二醛（ＭＤＡ）、内皮素和透明质酸，肝组织ＭＤＡ、ＡＴＰ和肝脏有效血流量等指标，并与对照组比较。结果：伤后２小时血中丙氨酸转氨酶、透明质酸含量明显增高，肝组织ＭＤＡ含量增多，而肝组织ＡＴＰ水平显著下降；伤后肝脏有效血流量低于伤前；血清内皮素含量明显升高，与肝血流量下降呈明显负相关。结论：肝脏损伤和某些毒素的作用与烫伤后肝血流量减少有关；后者则可能与血容量减少、血液再分配有关，其中肝窦内皮细胞的改变起重要作用。     

加贝酯对肝脏缺血再灌注损伤的保护作用

[目的]探讨加贝酯对SD大鼠肝脏抗缺血再灌注损伤（HIRI）的效应及其可能的机制。[方法]采用Pringle＇s法建立大鼠HIRI模型,将40只SD大鼠随机分成四组,每组10只：A组（假手术组）、B组（模型组）、C组（加贝酯处理组）、D组（盐水对照组）。分别测定血浆中天冬氨酸转氨酶（AST）、丙氨酸转氨酶（ALT）浓度;测定肝组织中丙二醛（MDA）、超氧化物歧化酶（SOD）含量及光镜观察各组病理形态学变化。[结果]B、C、D三组ALT、AST、MDA均显著高于A组（P〈0．05或P〈0．01）,B、D两组又显著高于C组（P〈0．01）;A组的SOD含量明显地高于其他三组,而C组又明显地高于B、D两组（P〈0．01）。光镜下观察肝组织形态学变化,A组形态基本正常;B、D两组损伤最严重;而C组较B、D两组轻微。[结论]肝脏缺血再灌注时,肝细胞功能受损,蛋白酶抑制剂加贝酯能明显减轻这种损伤,保护肝功能。     

Effects of KR-33028, a novel Na+/H+ exchanger-1 inhibitor, on ischemia and reperfusion-induced myocardial infarction in rats and dogs

The present study was performed to evaluate the cardioprotective effects of KR-33028, a novel Na+/H+ exchanger subtype 1 (NHE-1) inhibitor, in rat and dog models of coronary artery occlusion and reperfusion. In anesthetized rats subjected to a 45-min coronary occlusion and a 90-min reperfusion, KR-33028 at 5 min before occlusion (i.v. bolus) dose-dependently reduced myocardial infarct size from 58.0% to 46.6%, 40.3%, 39.7%, 33.1%, and 27.8% for 0.03, 0.1, 0.3, 1.0, and 3.0 mg/kg respectively (P < 0.05). In anesthetized beagle dogs that underwent a 1.0-h occlusion followed by a 3.0-h reperfusion, KR-33028 (3 mg/kg, i.v. bolus) markedly decreased infarct size from 45.6% in vehicle-treated group to 16.4% (P < 0.05), and reduced the reperfusion-induced release in creatine kinase myocardial band isoenzyme (MB), lactate dehydrogenase, troponin-I, glutamic oxaloacetic transaminase, and glutamic pyruvic transaminase. In separate experiments to assess the effects of timing of treatment, KR-33028 (1 mg/kg, i.v. bolus) given 10 min before or at reperfusion in rat models also significantly reduced the myocardial infarct size (46.3% and 44.1% respectively) compared with vehicle-treated group. In all studies, KR-33028 caused no significant changes in any hemodynamic profiles. In an isolated rat heart model of hypothermic cardioplegia, KR-33028 (30 mum), which was added to the heart preservation solution (histidin-tryptophan-ketoglutarate) during hypothermic cardioplegic arrest, significantly improved the recovery of left ventricular developed pressure, heart rate and dP/dt(max) after reperfusion. Taken together, these results indicate that KR-33028 significantly reduced the myocardial infarction induced by ischemia and reperfusion in rats and dogs, without affecting hemodynamic profiles.     

Sulfation of Lithocholate as a Possible Modifier of Chenodeoxycholic Acid-induced Elevations of Serum Transaminase in Patients with Gallstones

Chenodeoxycholic acid (CDC), through its metabolite, lithocholic acid (LC), is hepatotoxic in certain species. The cause of elevations of serum transaminase in 25% of humans ingesting CDC, however, is unknown, but also may be due to LC. Because efficient hepatic sulfation of LC may protect against hepatic injury, the aim of this study was to determine if sulfation of LC might modify CDC-induced elevations of transaminase. Pretreatment sulfation fraction (SF) was estimated in 63 randomly selected patients with gallstones in a double-blind randomized trial of CDC, 750 mg/d, 375 mg/d, or placebo; in 27 of these, SF was repeated at 1 or 2 yr. In four other patients, the SF was measured at 2 yr only. Serum glutamic oxaloacetic transaminase and serum glutamic pyruvic transaminase were determined monthly for 3 mo and then every 3 or 4 mo; an elevation of transaminase was defined as > 150% of the normal upper limit in asymptomatic patients. 10 μCi of ³H-glyco-LC (sp act 84 mCi/mol) was ingested 10-12 h before fasting duodenal biliary drainage. Bile acids in bile were separated by thin-layer chromatography. The SF was estimated as a percentage of total radioactivity (scintillation counting) in sulfated glyco-LC. The standard deviation for replicate SF determinations (n = 311) was 2.1% The pretreatment SF (mean 60.7±1.7 SEM) correlated inversely with age (r = 0.336, P < 0.005) and directly with the obesity index (r = 0.495, P > 0.001), but was independent of sex. The SF, remeasured at 1 or 2 yr, did not change significantly with time or CDC. Among CDC-treated patients, elevations of transaminase occurred in 75% of patients with a SF < 45% vs. 11% with a SF > 45% (P < 0.001). In conclusion, a SF < 45% occurred in patients with gallstones who had a high probability of developing elevated serum transaminase when treated with CDC. Thus, sulfation of lithocholate may modify CDC-induced elevations of serum transaminase.