Cross-Tolerance Between Acute Alcohol Intoxication and Endotoxemia

This study tests two hypotheses: (1) prior exposure to LPS induces cross-tolerance for the hepatic effects of subsequent short-term alcohol intoxication; and (2) short-term alcohol intoxication renders the liver resistant to the effects of acute endotoxemia, resulting in reduced production of superoxide and tumor necrosis factor. In the first group of experiments, male Sprague-Dawley rats were treated intravenously with E. coli lipopolysaccharide (LPS) (0.5 mg/kg) 48 hr before they were given an intravenous bolus of ethanol (1.75 g/kg), followed by 250–300 mg/kg/hr) for 3–5 hr. Superoxide release in the perfused liver was measured after the 3-hr ethanol infusion. Pre-treatment with LPS attenuated ethanol-mediated superoxide anion release by the perfused liver. The stimulatory effect of phorbol myristate acetate on hepatic release of superoxide was also decreased. In the second group of experiments, rats previously treated with ethanol for 5 hr, received an intravenous injection of LPS (1 mg/kg). At 90 min after LPS, sera were collected for tumor necrosis factor a assay. Hepatic release of superoxide anion was determined 3 hr after LPS. Acute ethanol intoxication for 5 hr significantly reduced LPS-induced serum tumor necrosis factor activity and free radical release by the perfused liver. LPS-induced mortality was also decreased. In both groups of experiments serum corticosteroid levels were reduced during cross-tolerance. These results demonstrate that cross-tolerance develops between acute alcohol intoxication and endotoxemia manifesting in reduced hepatic production of cytotoxic cytokines and superoxide anions.     

Acute Ethanol Intoxication Suppresses E. Coli Lipopolysaccharide Enhanced Glucose Utilization by Hepatic Nonparenchymal Cells

During infection or endotoxemia, the immune system is activated and its energy needs increase. Alcohol (ETOH) intoxication on the other hand suppresses the immune system and increases susceptibility to infection. Since the liver is the primary site both for metabolism of ETOH and detoxification of bacterial lipopolysaccharides (LPS), this investigation was directed at studying the effect of acute ETOH intoxication on the LPS-induced enhancement of in vivo glucose utilization in different types of hepatic cells. Rats were given an intravenous (IV) injection of ETOH followed by a constant infusion for 7 hr to maintain blood alcohol levels at about 175 mg/dl. E. coli LPS was administered IV at 4 hr and in vivo glucose utilization by the different types of liver cells was estimated 3 hr later using the 14C-2-deoxyglucose technique. Hepatocytes (HP), Kupffer (KC), and endothelial cells (EC), as well as the sequestered polymorphonuclear leukocytes (PMN), were separated from the liver by collagenase-pronase digestion followed by centrifugal elutriation and Ficoll-Hypaque density gradient centrifugation. The number of PMN in the liver was increased several-fold 3 hr after LPS administration. The presence of ETOH did not inhibit the LPS-induced neutrophil migration into the liver. ETOH depressed the LPS-induced increase in glucose uptake in both EC and KC by 50 to 80%, respectively. It also reduced the LPS-induced increase of plasma tumor necrosis factor activity by 80%. ETOH alone did not produce any significant changes in the parameters studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Superoxide Anion Release Into the Hepatic Sinusoid After an Acute Ethanol Challenge and Its Attenuation by Kupffer Cell Depletion

Superoxide anion release into the hepatic sinusoids and subsequent damage to the endothelial cells of the hepatic sinusoids after ethanol challenge was examined. A 250 mg/kg body weight/hr dose of ethanol was given to rats for 3 hr, and superoxide anion release into the hepatic sinusoids was examined in a liver perfusion model using the cytochrome c method. Ethanol treatment resulted in superoxide anion release into the hepatic sinusoids (0.20 ± 0.01 vs. 0.12 ± 0.02 o.d., p < 0.05) and an increase in the purine nucleoside phosphorylase/alanine aminotransferase ratio in the liver perfusate, a marker of damage to the endothelial cells of the hepatic sinusoids (0.003 ± 0.002 vs. 0.008 ± 0.002; p < 0.05). Tumor necrosis factor-alpha was not detectable in either group, and there were no significant differences in the population of hepatic macrophages, leukocytes, or Kupffer cells between the two groups. To clarify the role of Kupffer cells in the mechanism, 10 mg/kg of body weight of gadolinium chloride was given to rats twice, 24 hr apart, resulting in depletion of ED2-positive cells from the hepatic lobules. The superoxide anion release after the ethanol challenge was significantly attenuated in the Kupffer cell-depleted rats, compared with the controls (0.14 ± 0.02;p <0.05, compared with ethanol alone). The change was associated with a significant decrease in the purine nucleoside phosphorylase/alanine aminotransferase ratio in the liver perfusate (0.004 ± 0.002; p < 0.05, compared with ethanol alone). Ethanol causes superoxide anion release into the hepatic sinusoid and subsequent damage to the sinusoidal endothelial cells. These changes were reduced by Kupffer cell depletion. This supports the view that Kupffer cell depletion has a protective effect on ethanol-induced liver injury.     

Alcohol Consumption in Rats Potentiates the Deleterious Effect of Gram-Negative Sepsis on Hepatic Hyaluronan Uptake

The role of hepatic sinusoidal endothelial cells (SECs) in the pathologic changes of the liver associated with alcohol consumption is not fully understood. The measurement of hyaluronan (HA) uptake by the SECs provides a useful means for assessing the functional state of these cells. In this study, we determined the effect of acute and chronic exposure to alcohol in rats in the absence and presence of subcutaneous Escherichia co/i-induced sepsis on plasma HA concentration and HA uptake by the isolated, perfused liver. Rats were administered ethanol (two doses of 0.2 g/100 g body weight, intraperitoneal, 24 and 15 hr before killing) or fed a liquid diet for 8–10 weeks, containing alcohol (36% of the total calories) or dextrin (in isocaloric amounts). Twenty-one hr before euthanizing for liver perfusion, animals were injected subcutaneously with live E. coli (sepsis) or sterile saline (control). Neither acute nor chronic alcohol exposure by themselves altered plasma HA levels. However, both treatments exacerbated the hyperhyaluronanemic effect of sepsis. Thus, in acutely alcohol-treated rats, sepsis induced a 187% (p &< 0.05) increase in plasma levels of HA, whereas in nonalcohol septic rats, the increase was only 54% (p &< 0.05). Likewise, sepsis resulted in a greater increase in the plasma levels of HA (871%) in alcohol-fed rats than it did in liquid diet, control-fed rats (323%, p &< 0.05). The rate of HA uptake by the isolated, perfused liver was not altered by either acute or chronic alcohol exposure. However, alcohol exposure markedly potentiated the inhibitory effect of sepsis on the capacity of the liver to take up HA. Thus, in acutely alcohol-treated rats, sepsis decreased HA uptake (60-80%, p &< 0.05), whereas in the corresponding nonalcoholic control group the decrease was evident only at the beginning of HA infusion. In chronically alcohol-fed rats, sepsis induced an 80% (p &< 0.05) inhibition of HA uptake, whereas in diet-fed control rats the inhibition was only 60% (p &< 0.05). The inhibition by sepsis of HA uptake by the isolated, perfused liver provides an explanation for the previously observed hyperhy-aluronanemia in septic humans and animals. Because alcohol alone does not alter HA metabolism, the results suggest that acute and chronic alcohol exposure influences the communication between liver cells leading to downregulation of HA clearance by SECs.     

Tumor Necrosis Factor-α Cell-Surface Receptors of Liver Parenchymal and Nonparenchymal Cells during Acute and Chronic Alcohol Administration to Rats

Tumor necrosis factor-α (TNF-α) has been shown to contribute to the alcohol [ethanol (ETOH)]-induced alteration of hepatic function. Therefore we tested the hypothesis that the hepatic action of TNF-α could be due, at least in part, to alterations in TNF-α cell-surface receptors of hepatic parenchymal (hepatocytes) and nonparenchymal (Kupffer and sinusoidal endothelial) cells. Rats were either acutely treated with ETOH by a primed, continuous 7-hr intravenous infusion of 20% (w/v) ETOH (30 mg/100 g body weight/h) or chronically fed an ETOH-containing liquid diet (5.2% ETOH, w/v, with ETOH as 36% of total calories) for 14 weeks. Control rats in the acute group were infused with sterile saline, whereas control rats in the chronic group were fed liquid diet containing dextrin to replace ETOH in isocaloric amounts. Three hr before killing, the rats were injected intravenously with Gram-negative bacterial lipopolysaccharide [(LPS) 100 /μg/100 g body weight] or saline. Hepatocytes, Kupffer cells, and sinusoidal endothelial cells were isolated after liver perfusion with collagenase (without pronase), separated by centrifugal elutriation, and used to determine the affinity (K_d) and capacity (B_max) of binding sites, using recombinant human-[¹²⁵l]TNF-α as the ligand. Two binding sites were detected on Kupffer cells and sinusoidal endothelial cells isolated from control animals: a high-affinity (K_d1, in the range of 150–200 PM), low-capacity (B_max1, in the range of 2–3 fmol/10⁶ cells) binding site and a low-affinity (K_d2, in the range of 2–9 nm), high-capacity (B_max2, in the range of 3–15 fmol/10⁶ cells) binding site. One binding site was detected on hepatocytes isolated from control rats (K_d1= 1.0 nm and a B_max= 95 fmol/10⁶ cells). Acute ETOH administration caused an increase in K_d1 on both Kupffer and sinusoidal endothelial cells; a decrease in K_d1 on hepatocytes; and an increase in K_d2, B_max1, and B_max2 on endothelial cells. A second binding site on hepatocytes (K_d2= 5.8 nm, S_max2= 186 fmol/10⁶ cells) was observed only in the ETOH-treated group after LPS administration. Chronic alcohol exposure markedly elevated K_d1 and S_max1 on hepatocytes. Overall, LPS-induced changes mimicked those induced by alcohol, except for a decrease in B_max1 on Kupffer cells of rats in the acute treatment group. Also, the liquid diet containing alcohol or dextrin abrogated the high-affinity, low-capacity binding sites on both Kupffer cells and sinusoidal endothelial cells, and low-affinity, high-capacity binding sites on the hepatocyte. After LPS administration, the high-affinity binding sites on Kupffer and sinusoidal endothelial cells were reexpressed. These data show that: (1) ETOH induces changes in both the capacity (B_max) and affinity (K_d) of TNF-α cell-surface receptors of hepatocytes, Kupffer cells, and sinusoidal endothelial cells; and (2) ETOH-induced changes are consistent with an increased sensitivity of these cells to the action of TNF-α.     

Acute Ethanol Intoxication Prevents Lipopolysaccharide-Induced Down Regulation of Protein Kinase C in Rat Kupffer Cells

Protein kinase (PK) C has been implicated in a number of cellular events, many of which are also known to be affected by ethanol (ETOH). ETOH intoxication is also known to impair immune function, thereby increasing the host's susceptibility to infection. The purpose of this study was to assess the effect of acute ETOH intoxication on PKC activity and its intracellular distribution in nonparenchymal liver cells following an E. coli lipopolysaccharide (LPS) challenge. The liver was chosen for the study because it is the primary site both for metabolism of ETOH and detoxification of gut derived bacterial products. Catheterized conscious rats were administered saline or ETOH (175 mg/100 g body weight as a bolus followed by a continuous, 7 hr infusion of 28 mg/100 body weight/hr). LPS was injected intravenously (100 micrograms/100 g body weight) 3 hr before the end of the saline or ETOH infusion. Kupffer and endothelial cells were isolated by collagenase-pronase digestion followed by centrifugal elutriation. PKC was assayed after extraction with digitonin containing buffer and partial purification on DE-52 cellulose minicolumns. LPS decreased PKC activity by 69% from control values. Although ETOH infusion alone did not affect PKC activity in Kupffer cells, it completely abrogated the LPS effect. A similar trend was observed for the endothelial cells. No significant differences were observed between groups with respect to the intracellular distribution of PKC. The down-regulation of PKC by LPS may represent a mechanism of functional adaptation of the immunocompetent cells to one of the cytokines, i.e., TNF, whose receptors are down regulated by activation of PKC.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of Acute and Chronic Alcohol Administration to Rats on the Expression of Interleukin-6 Cell-Surface Receptors of Hepatic Parenchymal and Nonparenchymal Cells

Rats were treated with alcohol either acutely (continuous, 7-hr intravenous infusion; blood alcohol levels ～35 mM) or chronically (liquid diet, 12–14 weeks). Three hr before killing, the animals received Gram-negative bacterial lipopolysaccharide (LPS) or saline. Hepatocytes, Kupffer cells, and liver sinusoidal endothelial cells were isolated by liver collagenase perfusion and centrifugal elutriation, and used for measurements of recombinant human [¹²⁵I]interleukin-6 binding. Dissociation constant (K_d) and the amount of cell-surface receptors (B_max) were measured on whole cells, at 4°C. Two binding sites were detected on all three cell types: high-affinity (K_d1, from 20 to 125 PM) and low-affinity (K_d2, from 0.2 to 2 nM), with low B_max (B_max from 0.4 to 12 fmol/10⁶ cells) and high B_max (B_max2, from 10 to 210 fmol/10⁶ cells). Hepatocytes displayed an 8-fold higher binding capacity for high-affinity sites (B_max1) than the other two cell types. Acute ethanol treatment induced the following significant changes in the binding parameters: a decrease in K_d1 for hepatocytes and Kupffer cells, an increase in B_max2 for hepatocytes, and a decrease in B_max1 for Kupffer cells. Although the control (nonalcoholic) liquid diet per se completely suppressed the high-affinity binding sites, alcohol-containing diet induced only one change: a significant increase in K_d2 for hepatocytes. No changes in the binding parameters were seen after LPS administration to the chronically treated group. In the acute group, LPS mimicked alcohol action on hepatocyte binding parameters. Alcohol blunted LPS effects. No changes were observed in the cytokine binding to Kupffer cells after LPS injection. The results show that alcohol alters interleukin-6 cell-surface receptor properties and receptor amount on hepatocytes and Kupffer cells. By demonstrating the presence of interleukin-6 receptors on non-parenchymal liver cells, our data also suggest that these cells may be involved in an autocrine loop-like response, which could be a target for alcohol action on the liver.     

Chronic Alcohol Intoxication Enhances the Expression of CD18 Adhesion Molecules on Rat Neutrophils and Release of a Chemotactic Factor by Kupffer Cells

Chronic alcohol intoxication has been associated with increased migration of inflammatory leukocytes to the liver that may contribute to the development of alcoholic hepatitis in susceptible individuals. Thus, this work was performed to examine the mechanism by which neutrophils [polymorphonuclear neutrophils (PMNs)] are sequestered in the liver during prolonged consumption of alcohol. Male Sprague-Dawley rats were fed with Sustacal supplemented by 36% alcohol, or isocaloric diet for 16 weeks. Circulating blood PMNs were collected and examined for CD18 ( β ₂-integrin) adhesion molecule expression. Monoclonal antibody 1F12, an anti-CD18 antibody and potent neutropenic agent, was used to detect CD18 on PMNs. More than 97% of neutrophils obtained from pair and ethanol-fed rats were positive for the antibody. Fluorescence intensity of fluorescein iso-thiocyanate-1F12 binding to PMNs from ethanol-fed rat was significantly enhanced 2-fold compared with the pair-fed controls. The release of chemoattractant and free radical-generating activity in culture supernatants of Kupffer cells was also examined. Twenty-four hr culture supernatants of Kupffer cells from chronic alcoholic rats enhanced the migration and superoxide anion generation by normal PMNs, compared with those of the pair-fed rats. Antirat interleukin-8 antiserum inhibited chemotactic activity and superoxide generating capacity of culture supernatants. These results suggest that upregulation of adhesion molecules on PMNs and chemotactic factor release from Kupffer cells may contribute, at least in part, to enhanced migration of inflammatory leukocytes to the liver during chronic alcohol intoxication.     

Effects of Acute Alcohol Intoxication and Paroxetine on Aggression in Men

Background:  The purpose of this study was to examine the role of the serotonin (5-HT) system in alcohol-related aggression.
Methods:  Specifically, we experimentally examined the effects of 5-HT augmentation on alcohol-related aggression in men ( n  =   56). After consuming either alcohol (mean blood alcohol concentration of 0.10%) or a placebo (no alcohol) drink, and taking either 20 mg of paroxetine (Paxil®) or a placebo pill, participants were provided the opportunity to administer electric shock to a (faux) opponent during a task disguised as a reaction-time game. Aggression was defined as the intensity of shock chosen and the frequency with which an extreme (clearly painful) shock was chosen. We predicted that 5-HT augmentation would be associated with lower aggressive behavior overall, and also reduce the aggression facilitating effects of acute alcohol intoxication.
Results:  The results indicated that alcohol intoxication increased aggression, particularly under low provocation. Paroxetine decreased aggression, particularly during high provocation. These effects, however, occurred independently of each other.
Conclusions:  The effect of alcohol on extreme aggression was moderated by previous aggression history, with more aggressive individuals showing greater alcohol-related increases in extreme aggression.     

Splenic Function and Alcohol Addiction

Severe hyposplenism has been recently documented in alcoholic liver disease, and it has been suggested that alcohol itself is important in the derangement of splenic function, despite a lack of evidence of a direct toxic effect of alcohol on the spleen. The aim of the present study was to assess splenic function in alcoholic patients without severe liver disease and to correlate these data with the degree and duration of alcohol intake. Fifty-two alcoholics, 31 subjects with current alcohol abuse (group A)—13 abstinent from alcohol for 1 to 6 months (group B) and 8 abstinent from alcohol for 6 months to several years (group C)—and 26 healthy social drinkers were studied. Splenic function was assessed by counting the percentage of pitted red cells. An in vitro experiment was performed to verify whether the presence of pitted red cells could be due to an effect of alcohol on red cell morphology. The percentage of pitted red cells in subjects from group A was significantly higher than in subjects from group 6 (p < 0.01), from group C (p < 0.005), and from controls (p < 0.001). There was no significant difference between group 6, group C, and controls. Ten subjects from group A and 1 from group B and no subject from group C had evidence of splenic hypofunction. There was no significant correlation between the percentage of pitted red cells and daily alcohol intake or years of alcohol addiction. In conclusion, our study shows that, in patients with alcoholism but without any severe liver damage, a significant but slight increase in pitted red cells is present. Further studies are needed to clarify whether this is due to a mild form of splenic hypofunction or merely indicates erythrocyte membrane alterations.     

白细胞介素-18在实验性重症急性胰腺炎肝损伤中的作用

自细胞介素（IL）-18是一种新发现的促炎细胞因子，其血清水平与重症急性胰腺炎（SAP）合并肝损伤明显相关，然而关于其在SAP急性损伤肝组织中的变化和意义鲜有报道。目的：研究IL-18在SAP大鼠肝组织中的表达．探讨IL-18在SAP肝损伤中的作用。方法：以4％牛磺胆酸钠胰胆管逆行注射诱导大鼠SAP模型。32只大鼠随机分为对照组和SAP6h、12h、18h组。动态测定血清淀粉酶、丙氨酸氨基转移酶（ALT）、天冬氨酸氨基转移酶（AST）水平和腹水量；光学显微镜下观察胰腺和肝组织损伤情况；以免疫组化方法检测IL-18在肝组织中的表达和定位：以蛋白质印迹法检测肝组织中IL-18前体和成熟IL-18的表达。结果：SAP组各时间点血清淀粉酶、ALT、AST水平均明显升高，腹水量增多，与对照组相比差异有统计学意义（P〈0．01），与胰腺和肝脏的组织病理学改变相一致。造模后IL-18在肝脏Kupffer细胞胞质中呈强阳性表达，阳性Kupffer细胞数增多，成熟IL-18表达明显增加，各时间点与对照组相比差异均有统计学意义，以12h组为著（P〈0．01）。结论：Kupffer细胞是肝脏成熟IL-18的主要来源．成熟IL-18表达上调可能在SAP早期肝损伤中发挥重要作用。     

不同剂量的阿托伐他汀对心肌损伤大鼠内皮祖细胞动员及血管内皮功能的影响

目的观察不同剂量的阿托伐他汀对心肌损伤后大鼠骨髓和外周血内皮祖细胞动员及血管内皮功能的影响。方法S-D大鼠背部皮肤多点注射异丙肾上腺素(5mg/kg)制造心肌损伤模型后,随机分为生理盐水对照组和不同剂量的阿托伐他汀组[5、10、20、40及80mg/(kg.d)]。4周后,流式细胞仪检测大鼠外周血CD34 和血管内皮生长因子受体2 双阳性细胞数。骨髓和外周血单个核细胞于M199培养基培养,FITC标记的异凝集素和DiI标记的乙酰化低密度脂蛋白染色双阳性细胞为正在分化的内皮祖细胞,倒置荧光显微镜计数3个随机高倍视野数。阿托伐他汀灌胃3天后测定血清一氧化氮浓度。结果阿托伐他汀各剂量组骨髓培养内皮祖细胞均较对照组明显增加(P<0.05),其中40mg/(kg.d)组内皮祖细胞数量最多,较对照组增加了2.4倍(P<0.05),80mg/(kg.d)组与40mg/(kg.d)组比较稍有下降,但无统计学差异;阿托伐他汀组外周血培养内皮祖细胞较对照组明显增加,40mg/(kg.d)组增加最明显(P<0.05);心肌损伤后外周血CD34 /血管内皮生长因子受体2 细胞较损伤前增加(P<0.05),其中80mg/(kg.d)组最明显,较对照组增加了4.18倍(P<0.05),40mg/(kg.d)组与80mg/(kg.d)组无统计学差异;阿托伐他汀各剂量组血清一氧化氮浓度较对照组明显增加,其中80mg/(kg.d)组增加最明显,并随剂量增加一氧化氮浓度增加。结论阿托伐他汀具有显著的剂量依赖性骨髓动员、促进外周血中内皮祖细胞迁移、改善血管内皮功能的作用。     

Liver Sinusoid during Chronic Alcohol Consumption in the Rat: An Electron Microscopic Study

Transmission and scanning electron microscopic studies were performed on the liver sinusoid, with emphasis on sinusoidal endothelial cells, in rats fed a liquid diet containing either alcohol or dextrin (control) for 14 weeks. Animals were also treated with either Gram-negative bacterial lipopolysaccharide (LPS; 100 μg/100 g body weight, intravenously) or sterile saline (control). All specimens were prepared after perfusion fixation of the liver. Livers of rats fed dextrin-containing liquid diet displayed the ultrastructural features typical of the sinusoid and its endothelial cells. Livers from alcohol-fed animals, however, were characterized by massive loss of sieve-plate architecture of the sinusosidal endothelium, which was virtually replaced with a meshwork of enlarged openings with diameters frequently exceeding 1 urn. Morphological evidence of Kupffer cell activation could also be seen along with significant fatty infiltration of the hepatocyte. Conversely, LPS administration to dextrin-fed animals induced an apparent decrease in fenestration of the sinusoidal endothelial cell, accompanied by morphological evidence of enhanced endocytotic activity and cytoplasmic swelling. The changes seen 3 hr after LPS administration were markedly advanced at 24 hr. LPS administration to alcohol-fed rats accentuated the alterations observed after alcohol treatment alone. Additionally, the presence of platelets in the sinusoid as well as adhering to the hepatocyte microvilli in the space of Disse, along with the presence of Ito and Kupffer cell activation, greater than that observed in the alcohol-treated rats, is morphological evidence consistent with the disruption of vascular integrity in the liver. Interestingly, LPS treatment did not reverse the effects of alcohol on the sinusoidal endothelial cell fenestration. The possible functional consequences of alcohol- and LPS-induced ultrastructural alterations of the sinusoidal endothelial cell, and of the hepatic sinusoid in general, are evaluated in light of the available data on scavenging function of the sinusoidal endothelial cell.     

通心络胶囊对同型半胱氨酸诱导的血管内皮细胞损伤的保护作用

目的 探讨通心络对同型半胱氨酸(homocysteine,Hcy)诱导的血管内皮细胞损伤的保护作用及机制.方法 体外培养人脐静脉内皮细胞(HUVEC),分为对照组、同型半胱氨酸组、通心络组和阿托伐他汀组,处理48 h后,采用MTT法观察内皮细胞的增殖情况;以荧光定量逆转录聚合酶链反应方法比较各组间超氧化物歧化酶(SOD)mRNA表达水平;检测细胞培养液的SOD活性和丙二醛含量.结果 Hcy组细胞活力较对照组明显降低(P＜0.05),通心络组和阿托伐他汀组细胞活力较Hcy组均明显改善(P＜0.05).Hcy组SOD mRNA表达水平显著低于对照组 (P＜0.05);通心络和阿托伐他汀组SOD mRNA表达水平均显著高于Hcy组(P＜0.05).Hcy组SOD活性较对照组显著下降(P＜0.05),丙二醛水平较对照组显著增加(P＜0.05).通心络组和阿托伐他汀组SOD活性均较Hcy组明显增加(P＜0.05),而丙二醛水平显著减少(P＜0.05).结论 通心络对同型半胱氨酸诱导的血管内皮细胞损伤有保护作用,其机制可能与其抗氧化作用有关.     

Chronic Alcohol Feeding in Liquid Diet or in Drinking Water Has Similar Effects on Electron Microscopic Appearance of the Hepatic Sinusoid in the Rat

Electron microscopic appearance of the liver sinusoid was examined in rats fed alcohol chronically in a complete liquid diet or in sucrose-containing drinking water. The animals were kept on liquid diet (±alcohol) for 14 weeks or on sucrose-containing drinking water (±alcohol) for 12.5 weeks and sacrificed thereafter. To rule out possible artifact induced by fixation procedure, livers were fixed by immersion (no perfusion), immersion preceded by perfusion, and by perfusion with glutaraldehyde and examined with both scanning and transmission electron microscopy. Regardless of the mode of its administration, and of the fixation procedure used, alcohol induced similar changes in liver sinusoid ultrastructure. Such changes included disruption of the sieve-plate pattern of the sinusoidal endothelial cell fenestrations with the appearance of large gaps and resulting in a meshwork lining, wherein large areas of the sinusoid communicated freely with the underlying hepatocytes. Transmission electron microscopy complemented these findings. The results reported in this study demonstrate that alcohol-induced structural changes of the liver sinusoid in the rat are similar whether alcohol is fed via a liquid diet or in drinking water. Therefore, alcohol administration in drinking water may provide a simple, inexpensive, and convenient method of inducing structural changes in the rat liver sinusoid.     

Free Radical Formation in Livers of Rats Treated Acutely and Chronically with Alcohol

The spin trapping method was used to assess formation of free radical intermediates in vivo before and after acute alcohol administration to rats. Ascorbyi radicals and spin adducts of dietary alcohol or endogenous compounds, such as lipids, were detected with higher frequency in bile from alcohol-fed rats than in corresponding samples from rats fed control diets. When alcohol was given acutely to these animals, the 1-hydroxyethyl radical metabolite of ethanol was also formed at higher rates in livers of rats that had been fed ethanol chronically. Furthermore, formation of lipid radicals was enhanced after acute alcohol administration. These data support the hypothesis that chronic alcohol administration causes development of oxi-dative conditions in the liver, which subsequently lead to formation of differing types of radicals. Liver microsomes from alcohol-fed rats also metabolized ethanol to the 1-hydroxyethyl radical at higher rates than controls.     

L-精氨酸对高糖引起内皮功能失调的保护作用

目的通过研究L-精氨酸和N^G-硝基-L-精氨酸-甲基酯对人脐静脉内皮细胞产生一氧化氮和超氧阴离子的影响以探讨L-精氨酸对高糖引起内皮功能失调的保护作用。方法不同浓度L-精氨酸、N^G-硝基-L精氨酸-甲基酯、葡萄糖和胰岛素加入体外培养的人脐静脉内皮细胞，24h后分别测定细胞培养液中一氧化氮舍酶和超氧化物歧化酶活性及一氧化氮和超氧阴离子浓度。结果25mmol／L葡萄糖使内皮细胞一氧化氮合酶活性增高，一氧化氮产生增加，超氧化物歧化酶活性下降，超氧阴离子产生增加；L-精氨酸对一氧化氮舍酶、一氧化氮、超氧化物歧化酶的影响与对照组相比无显著性差异（P〉0．05）。但可以使超氧阴离子产生减少；25mmol／L葡萄糖＋L-广精氨酸使内皮细胞一氧化氮舍酶活性增强，一氧化氮产生增加，L-精氨酸可以改善高糖引起的超氧阴离子升高。不同浓度的胰岛素使内皮细胞一氧化氮合酶活性增高，一氧化氮产生增加，对超氧化物歧化酶活性和超氧阴离子产生无明显影响；不同浓度胰岛素＋L-精氨酸使内皮细胞一氧化氮合酶活性增强，一氧化氮产生增加，对超氧化物歧化酶活性无明显影响，但可以使超氧阴离子水平降低。100μmol／LN^G-硝基-L-广精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降，一氧化氮产生减少，对超氧化物歧化酶活性无明显影响，但使超氧阴离子产生增加；25mmol／L葡萄糖＋N^G-硝基-L-精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降，一氧化氮产生减少，但对高糖引起的超氧化物歧化酶活性下降和超氧阴离子升高无明显影响。10mu胰岛素＋10μmol／L N^G-硝基-L-精氨酸．甲基酯和100mu胰岛素＋100μmol／L N^G-硝基-L-精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降，一氧化氮产生减少，对超氧化物歧化酶活性无明显影响，但使超氧阴离子升高。结论L-精氨酸对一氧化氮合酶、一氧化氮、超氧化物歧化酶无明显影响，但可以使超氧阴离子产生减少；N^G-硝基-L-精氨酸-甲基酯使内皮细胞一氧化氮合酶活性下降。一氧化氮产生减少，对超氧化物歧化酶活性无明显影响，但使超氧阴离子产生增加。     

内毒素刺激Kupffer细胞对肝星状细胞前胶原基因表达的影响

背景：肠源性内毒素血症对肝纤维化具有启动作用,肝星状细胞（HSC）活化是肝纤维化发生、发展的中心环节。目的：探讨内毒素刺激Kupffer细胞对HSC前胶原基因表达的影响及其可能机制。方法：改良链酶蛋白酶、胶原酶原位灌流和密度梯度离心分离大鼠肝脏Kupffer细胞和HSC。以RNA斑点杂交检测脂多糖（LPS）、Kupffer细胞、LPS与Kupffer细胞共培养和肿瘤坏死因子-α（TNF-α）对HSC前胶原mRNA表达的影响,放射免疫法检测LPS对Kupffer细胞和HSC产生TNF-α的影响,RNA印迹法检测LPS和TNF-α对Kupffer细胞和HSC转化生长因子-β（TGF-β）mRNA表达的影响结果：经低浓度（0.5、1、5μg/ml）LPS处理的Kupffer细胞培养上清可增加HSCⅠ、Ⅲ、Ⅳ型前胶原mRNA表达,经高浓度（10、15、20μg/ml）LPS处理的Kupffer细胞培养上清、单独LPS、未经处理的Kupffer细胞培养上清、单独TN-α均无此作用。Kupffer细胞培养上清中的TNF-α含量随LPS浓度梯度的增加而递增,HSC培养上清中的TNF-α含量则无明显变化。TNF-α不能增加HSC TGF-βmRNA表达,但能增加Kupffer细胞TGF-βmRNA表达;经LPS或TNF-α处理的Kupffer细胞培养上清能增加HSC TGF-βmRNA表达。结论：低浓度内毒素能上调HSC前胶原基因表达,该作用有赖于内毒素激活Kupffer细胞所产生的活性介质的参与。