趋化因子及其共同受体在慢性乙型肝炎发病机制中的作用

趋化因子通过与其受体的相互作用,招募外周血中的淋巴细胞到达肝脏炎症部位,介导HBV感染后的病毒清除与免疫损伤的过程.此文就趋化因子IFN诱导蛋白10(IP-10)、LFN-γ诱生单核因子(MIG)、IFN诱导T细胞趋化因子(I-TAC)及其共同受体CXCR3在慢性乙型肝炎发病中的作用进行综述.     

Glutamine and CXC chemokines IL-8, Mig, IP-10 and I-TAC in human intestinal epithelial cells

BACKGROUNDS & AIMS: Chemokines are a family of small proteins involved in immune and inflammatory responses. Human intestinal epithelial cells act as a sentinel in the immune response and produce CXC chemokines such as IL-8, Mig, IP-10 and I-TAC. Glutamine has various effects on immuno-inflammatory response in human intestine. METHODS: The present study aimed to determine the effect of glutamine on the IL-8, Mig, IP-10 and I-TAC production by ELISA and their mRNA level by RT-PCR (expressed as % gapdh) in two human intestinal epithelial cell lines Caco-2/TC7 and HCT-8 under basal conditions or during stimulation with combined cytokines. RESULTS: Under basal conditions, studied chemokines were not influenced by glutamine. When intestinal epithelial cells were stimulated with cytokines, increasing concentrations of glutamine from 2 to 10 mM in HCT-8 cells significantly decreased I-TAC and IP-10 mRNA level (respectively 219 to 182%; P < 0.01; 257 to 176%; P < 0.05) and I-TAC and IP-10 production (respectively 21.2 to 13.0; P < 0.05; 696 to 548 ng/prot mg; P < 0.01). Glutamine also reduced IP-10 mRNA level (186 to 135%, P < 0.05) in cytokines-stimulated Caco-2/TC7 cells. CONCLUSIONS: Down-regulation of CXC chemokines by glutamine could contribute to its therapeutic potential in intestinal inflammation and during critical illness.     

Immune response modulation in acutely ethanol-intoxicated, acutely diabetic male and female rats.

We examined how acute diabetes mellitus and acute ethanol intoxication modulate factors that mediate immune responses as a basis for explaining the increased susceptibility to infection in these two conditions. Our working hypothesis is that ethanol intoxication in diabetes compromises host defense mechanisms to a greater extent than observed in each condition alone. Male and female rats were made diabetic with streptozotocin (65 mg/kg, i.p.). Forty-eight hours after administration of streptozotocin, rats either received no treatment (control group) or were treated with (1) ethanol (bolus injection of 1.75 g/kg, followed by a 3-h infusion at the rate of 300 mg/kg/h), (2) lipopolysaccharide [(LPS); 0.9 mg/kg], or (3) a combination of LPS+ethanol. At the end of 3 h, rats were killed, and the livers were digested by perfusion with collagenase-containing Hanks' balanced salt solution to isolate hepatocytes and Kupffer cells. To measure chemokine generation, hepatocytes (2.5x10(5) cells per well) and Kupffer cells (1x10(6) cells per well) were cultured for 20 h, and the supernatant was used to measure cytokine-induced neutrophil chemoattractant (CINC) and regulated on activation, normal T-cell expressed and secreted (RANTES) chemokines. Phagocytosis by Kupffer cells was measured by flow cytometry and expressed as mean channel fluorescence intensity (MCF). Induction of diabetes as well as treatment of nondiabetic rats with LPS, ethanol, or LPS+ethanol caused depression of MCF values of Kupffer cells. However, treatment of the diabetic male and female rats with LPS and LPS+ethanol increased the MCF values relative to those of Kupffer cells obtained from untreated diabetic rats, but administration of ethanol to diabetic rats did not have a similar effect. The induction of diabetes caused an increase in CINC generation by Kupffer cells obtained from male rats, but not from female rats. This diabetes-induced elevation of chemoattractant factor was decreased when diabetic animals were treated with LPS, ethanol, or LPS+ethanol, and the sex difference was obliterated. Thus, the induction of diabetes as well as treatment with LPS, ethanol, or LPS+ethanol in nondiabetic rats depressed the phagocytic capability of Kupffer cells, whereas the presence of endotoxemia (administration of the endotoxin LPS) or administration of LPS+ethanol reversed the diabetic effect, but ethanol intoxication did not. These findings seem to indicate a persistence of depression of host defense capacity in the ethanol-intoxicated diabetic condition. This is further reinforced by the depression of the diabetes-induced enhancement of chemotaxis when the diabetic rats became intoxicated.     

Neutrophilic infiltration in alcoholic hepatitis.

Leukocyte infiltration in the liver is one of the most important features of alcoholic liver disease. However, in alcoholic hepatitis, the role of polymorphonuclear neutrophils (PMNs) in liver injury still remains to be fully elucidated. Furthermore, the migration of PMNs and their presence in the liver during alcoholic hepatitis have not been fully investigated. Up-regulation of chemokine secretion and adhesion molecule expression on effector cells (i.e., PMNs) and target cells (i.e., hepatocytes) are important factors in neutrophilic infiltration of the liver. The CXC chemokines--that is, interleukin (IL)-8 (in human beings), cytokine-induced neutrophil chemoattractant (CINC) (in rats), and KC (in mice)--are proneutrophilic agents. They are up-regulated during chronic--that is, several years of--alcohol use in human beings and in up to 30 weeks in experimental models of ethanol intoxication in mice and rats. Up-regulation of these chemokines in the circulation and tissues is also associated with enhanced neutrophilic infiltration in the liver. In the rat, the up-regulation of CXC chemokine production is time dependent. For example, after 16 weeks of feeding, up-regulation of CXC chemokine is observed, whereas after 32 weeks, CC chemokines are enhanced. Concomitantly, selective migration of PMNs and mononuclear cells is observed. In another model, in which both CXC and CC chemokines were enhanced after chronic ethanol use for 12 weeks in mice, neutrophilic and mononuclear/lymphocytic infiltrations were also seen. This model correlates closely with alcoholic hepatitis in human beings, characterized by increased IL-8, RANTES (regulated upon activation, normal T cell expressed and secreted), and macrophage inflammatory protein-1 (MIP-1) and profound increases in neutrophils and lymphocytes in the liver.     

Chemokine CXCL10 (IP-10) is sufficient to trigger an immune response to injected antigens in a mouse model

The induction of chemokines by interferons might represent a link between innate and adaptive immunity. Whether these induced chemokines might be useful by themselves to induce an immune response is not known. We hypothesized that the interferon-inducible chemokine CXCL10 could stimulate dendritic cells (DC) to mature and cross-present exogenous antigen to T cells, resulting in a Th1-type immune response. We found that injecting mice with CXCL10 together with ovalbumin (OVA) as a test antigen was sufficient to produce functional OVA-specific T cells in 7 of 10 mice. Further, using only CXCL10 and a peptide antigen derived from vaccinia virus, we were able to induce peptide-specific cytotoxic T cells in 4 of 4 mice tested. These cytotoxic T cells protected 9 of 10 mice from subsequent infectious challenge with vaccinia virus. Unlike traditional adjuvants, no side effects were observed in any of the injected mice. We conclude that CXCL10 co-administration with a variety of antigens may represent a unique strategy of inducing a protective T cell response to a number of pathogens that merits further study.     

Acute alcohol intoxication and gadolinium chloride attenuate endotoxin-induced release of CC chemokines in the rat.

This work tests the hypotheses that Kupffer cells are a major source of CC-chemokines (MIP-1alpha, MCP-1, RANTES) during acute endotoxemia and that acute ethanol intoxication modulates Escherichia coli lipopolysaccharide (LPS, 1 mg/Kg, i.v.)-induced chemokine release in the rat. LPS stimulated the release of CC-chemokines into the circulation, hepatic sequestration of leukocytes and liver injury. LPS-induced serum chemokines peaked at 1-3 h and could not be detected at 24-h posttreatment. Splenectomy significantly suppressed LPS-induced RANTES release, but not MIP-1alpha and MCP-1. Kupffer cell depletion by gadolinium chloride or acute ethanol intoxication significantly attenuated LPS-induced CC-chemokine release and hepatic injury. Hepatic sequestration of leukocytes during endotoxemia was also suppressed by acute ethanol. LPS downregulated the expression of MIP-1alpha and MCP-1 mRNAs and upregulated RANTES mRNA in Kupffer cells at 3-h post endotoxin. The expression of mRNAs was further suppressed in ethanol plus the LPS-treated group. Ethanol also suppressed the LPS-mediated priming of Kupffer cells for enhanced CC-chemokine release in vitro. Ethanol alone significantly upregulated the expression of CC-chemokine mRNA, and primed the Kupffer cells for enhanced RANTES release. CC-chemokine release and mRNA expression in hepatic sinusoidal endothelial cells were not significantly altered by ethanol, except for MCP-1 release. These data show that acute ethanol may be beneficial in tissue injury during acute endotoxemia.     

The Canarypox-virus vaccine vector ALVAC triggers the release of IFN-gamma by Natural Killer (NK) cells enhancing Th1 polarization

We investigated the mechanism by which ALVAC activates innate immunity. Combining ALVAC with protein antigens significantly augmented antigen-specific IgG2a responses; this was dependent on the presence of bioactive interferon (IFN)-gamma. Immuno-depletion of NK cells prior to ALVAC immunisation abrogated IFN-gamma production indicating that they are the main cellular source of early IFN-gamma in vivo. Murine bone-marrow derived dendritic cells (BMDCs) cultured in the presence of ALVAC secreted high levels of the chemokines CXCL10 and CCL2 and up-regulated expression of the maturation markers CD40, CD80 and CD86. Therefore, we conclude that ALVAC acts as an adjuvant through a mechanism requiring NK cell derived IFN-gamma, DC activation and chemokine secretion.     

Chronic ethanol intoxication enhances the production of cytokine-induced neutrophil chemoattractant and macrophage inflammatory protein-2 by hepatocytes after human immunodeficiency virus-1 glycoprotein 120 vaccination.

Chemokines are implicated in the pathogenesis of alcoholic liver disease and human immunodeficiency virus-1 (HIV-1) infection. Thus, this work examined the regulation of chemokines --i.e., cytokine-induced neutrophil chemoattractant (CINC) and macrophage inflammatory protein-2 (MIP-2)--produced by hepatocytes after HIV-1 glycoprotein 120 (gp120) vaccination in Wistar rats fed with ethanol for 30 weeks. HIV-1 gp120 in complete Freund's adjuvant was given by intrainguinal route at a dose of 5 g/kg, followed by two booster shots in incomplete Freund's adjuvant at a weekly interval. Samples were taken 1 week after the last injection was given. Results show that anti-HIV-1 gp120 antibody titer was suppressed by 40% in the ethanol-fed rats, compared with findings in the parallel controls. However, serum CINC and MIP-2 levels were more elevated in the ethanol-fed rats than in the pair-fed group. The likely sources of these chemokines are the hepatocytes. After HIV-1 gp120 treatment, isolated hepatocytes obtained from the ethanol-fed group produced more CINC and MIP-2 than did those of pair-fed rats. Concomitantly, mRNA expression for these two chemokines and hepatic sequestration of neutrophils were upregulated. Ethanol feeding alone suppressed chemokine release, but it did not alter mRNA expression in isolated hepatocytes. Administration of Freund's adjuvant (without HIV-1 gp120) did not induce chemokine release in vivo and did not prime isolated hepatocytes for enhanced chemokine production in vitro. These results show that chronic ethanol intoxication affects the ability of the host to respond to HIV-1 gp120 vaccination.     

Alcohol and immunology: introduction to and summary of the 2003 Alcohol and Immunology Research Interest Group (AIRIG) meeting.

The 8th Meeting of the Alcohol and Immunology Research Interest Group (AIRIG) was held at Loyola University Medical Center, Maywood, Illinois, USA, on November 21, 2003. Reports from multiple laboratories reveal that the functional integrity of the immune system is of paramount importance to the survival of the individual after infection or injury. Evidence supports the idea that exposure to alcohol causes dysregulation of both the innate and the adaptive arms of the immune system. Gaining a better understanding of how alcohol interferes with normal inflammatory and immunoregulatory processes will aid researchers in the design of therapeutic interventions that can be used to improve these responses to better fight infection and maintain the health of the individual. At this meeting, nine speakers presented a summary of their recent work on the combined effects of ethanol and injury, infection, or inflammatory challenge. Topics were (1) T-cell activation after chronic ethanol ingestion in mice, (2) effect of ethanol consumption on the severity of acute viral-mediated pancreatitis, (3) ethanol and alveolar macrophage dysfunction, (4) impaired intestinal immunity and barrier function: a cause for enhanced bacterial translocation in alcohol intoxication and burn injury, (5) immune consequences of the combined insult of acute ethanol exposure and burn injury, (6) consequences of alcohol-induced dysregulation of immediate hemodynamic and inflammatory responses to trauma/hemorrhage, (7) regulation of tumor necrosis factor-alpha production by Kupffer cells after chronic exposure to ethanol, (8) acute exposure to ethanol and suppression of cytokine responses induced through Toll-like receptors, and (9) inhibition of antigen-presenting cell functions by alcohol: implications for hepatitis C virus infection. We anticipate that the work presented at the 8th Meeting of AIRIG, summarized in this article, and presented in the nine articles to follow in this Special Issue of Alcohol will stimulate ideas that will develop into research projects in these topical areas.     

Production of biologically active CXC chemokines by Lactococcus lactis: evaluation of its potential as a novel mucosal vaccine adjuvant

Chemokines have been described as essential mediators in leukocytes migration to inflammatory sites and to secondary lymphoid organs. Mig and IP-10 are two CXC chemokines that recruit mononuclear cells in vivo and inhibit angiogenesis. In addition to their chemotactic roles, Mig and IP-10 have also an important role in the adaptative immune response. In this study, we asked whether a food-grade bacterium, Lactococcus lactis, is able to produce a fusion protein comprising Mig and IP-10 (Mig::IP-10). The activity of the recombinant Mig::IP-10 produced by the genetically engineered L. lactis (LL-Mig::IP-10) was confirmed in a murine spleen cells chemotaxis assay. Moreover, the adjuvant properties of LL-Mig::IP-10 strain were evaluated in mice by the co-expression of a model antigen, the human papillomavirus type 16 E7 protein. Our data show that LL-Mig::IP-10 can produce a genetic fusion of Mig::IP-10 biologically active. This recombinant strain represents a potential candidate for the development of new strategies for mucosal vaccination.     

急性期川崎病与过敏性紫癜患儿血浆趋化因子的比较

目的:探讨川崎病(KD)与过敏性紫癜(HSP)发病机制中炎性细胞的参与是否存在差异。方法:通过采用酶联免疫吸附试验(ELISA)检测确诊的15例急性期KD患儿、12例HSP患儿及10名健康对照组儿童的血浆干扰素诱导蛋白10(IP-10)和单核细胞趋化蛋白1(MCP-1)水平,判断KD与HSP发病机制中单核细胞参与的情况。结果:KD组IP-10(394.2±176.4)pg/m l和MCP-1(420.5±163.4)pg/m l水平较HSP组IP-10(94.8±66.4)pg/m l和MCP-1(109.2±76.6)pg/m l水平均明显升高,差异性显著(P<0.05);但HSP组与对照组IP-10(76.4±46.5)pg/m l和MCP-1(87.7±47.8)pg/m l水平比较,差异不明显(P>0.05)。结论:单核细胞在KD发病机制中可能发挥着重要的作用;与其相比,在HSP发病机制中可能不涉及单核细胞参与。     

Mucosal vaccination increases local chemokine production attracting immune cells to the stomach mucosa of Helicobacter pylori infected mice

Background

Vaccination is an attractive approach for the prevention of Helicobacter pylori infection and disease. In a mouse model, infection induces an accumulation of dendritic cells, macrophages, granulocytes, and B- and T cells to the stomach mucosa, which is further heightened when the infection is preceded by a mucosal immunization. We have studied the chemokines and chemokine receptors guiding infection- and vaccination-induced immune cells to the stomach and their relation to protection against H. pylori infection in mice.

Materials and methods

C57BL/6 mice were immunized sublingually with H. pylori lysate antigens and cholera toxin adjuvant or left unimmunized, and then challenged with live H. pylori bacteria. Stomach tissue was taken at 3, 7, 14 and 21 days after challenge and bacterial colonization, chemokine and chemokine receptor gene expression, and influx of cells into the stomach mucosa were evaluated.

Results

RT-PCR array screening revealed differential expression of a broad range of chemokine and chemokine receptor genes between immunized and unimmunized mice. A significant upregulation of chemokines known to attract, among other cells, eosinophils (CCL8), T cells (CXCL10, CXCL11) and neutrophils (CXCL2, CXCL5) and of their cognate receptors CCR3, CXCR3 and CXCR2, preceded or coincided with vaccine-induced protection, which was first evident 7 days after infection and was then sustained at the later time-points. Consistent with the increase in chemokines and chemokine receptors flow cytometric analysis indicated a sequential accumulation of CD4⁺ T cells, eosinophils, neutrophils and CD103⁺ dendritic cells in the gastric lamina propria of immunized mice.

Conclusions

This study provides insights into vaccination-induced chemokines that guide the influx of protective immune cells into the stomach of H. pylori infected mice.     

Acute alcohol intake impairs lung inflammation by changing pro- and anti-inflammatory mediator balance.

Previous studies have shown that alcohol (ethanol [EtOH]) intoxication impairs lung immunity by affecting cytokines pivotal to the inflammatory process. The objective of this study was to test the hypothesis that acute alcohol intoxication impairs lung innate immunity by downregulating the expression of proinflammatory mediators while simultaneously upregulating anti-inflammatory mediators. EtOH was administered to the mice 0.5h prior to an intratracheal injection of Escherichia coli lipopolysaccharide (LPS). The animals were killed either 4 or 24h after LPS to recover plasma, lungs, and bronchoalveolar lavage fluid. Lung inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), IL-6, macrophage inhibitory factor (MIF), IL-10, TGF-beta, and receptors for TNF-alpha, IL-1beta, IL-6, and TGF-beta as well as glycoprotein (gp)130 and corticosterone (CS) levels were evaluated at mRNA and protein level. While the mRNA expression and the soluble TNF-Rp55 levels were significantly upregulated by EtOH, LPS-induced TNF-alpha activity, TNF-Rp55 mRNA expression, and soluble TNF-Rp55 levels were significantly suppressed. The LPS-induced expression of IL-1beta, IL-6, MIF, gp130, and receptors IL-1RI, IL-1RII, and IL-6Ralpha were also significantly impaired by EtOH. EtOH increased significantly the basal IL-10 activity at 3h, which continued to remain elevated even at 24h. The EtOH effect on IL-10 activity persisted even in LPS-challenged mice. EtOH and LPS augmented lung CS levels independently of each other. EtOH suppressed upregulation of TGF-beta1 mRNA expression by LPS and blocked completely LPS-induced TGF-beta1 secretion. In conclusion, the data suggest that the suppression of acute lung inflammation by EtOH intoxication is largely due to impairment by EtOH of proinflammatory cytokine signaling at the levels of cytokine expression and secretion as well as receptor expression and soluble receptor activity. The augmentation by EtOH of anti-inflammatory mediators' secretion most likely shifts the cytokine balance in the anti-inflammatory direction.     

CXC趋化因子配体3与相关疾病的研究进展

CXC趋化因子配体(CXCL)3是由多种细胞分泌的一种低相对分子质量的生物活性蛋白质，主要通过招募和活化多种表达CXC趋化因子受体(CXCR)1、2的细胞，参与细胞迁移、侵袭及血管新生等调控，在妊娠相关疾病、肿瘤、心血管疾病及肺部疾病发生、发展中具有重要作用。阻断CXCL3或CXCR1、2信号传导通路，可抑制细胞迁移、侵袭、血管生成、肿瘤发生及纤维化等病理生理过程，这可能成为多种疾病的潜在防治靶点。笔者拟就CXCL3与妊娠相关疾病、肿瘤、心血管疾病及肺部疾病关系的最新研究进展进行阐述，旨在发现CXCL3在上述疾病发病机制中的具体作用，为临床采取新策略诊断及分子靶向治疗上述疾病提供参考。     

Individual alcohol reaction profiles

The purpose of this study was to evaluate interindividual variation in acute reactions to ethanol. Six young, healthy female subjects participated in a double-blind experiment consisting of two identical alcohol sessions and one control session where glucose was infused instead of ethanol. Alcohol was infused in a standardized way to reach blood alcohol concentration of 1 mg/ml in 1 hr. During the 4 hr-sessions EEG-spectra, smooth pursuit eye movements, various mood variables, BAC and breath alcohol concentrations were studied repeatedly. The results showed that the subjects had a rather repeatable, individual reaction profile as expressed by changes in alpha mean frequency, theta band power, amount of corrective eye movements and subjective intoxication. The sensitivity of the subject to ethanol should thus be expressed as a reaction profile rather than as a change in a single variable.     

Consequences of alcohol-induced early dysregulation of responses to trauma/hemorrhage.

Acute alcohol intoxication is a frequent underlying condition associated with traumatic injury. Studies from our laboratory have been designed to examine the early hemodynamic, proinflammatory, and neuroendocrine alterations in responses to hemorrhagic shock in surgically catheterized, conscious, unrestrained, male Sprague-Dawley rats during acute alcohol intoxication (1.75-g/kg bolus, followed by a constant 15-h infusion at a rate of 250-300 mg/kg/h). With both fixed-pressure (40 mm Hg) and fixed-volume (50%) hemorrhagic shock, followed by fluid resuscitation with Ringer's lactate, acute (15 h) alcohol intoxication has been shown to impair significantly the immediate hemodynamic, metabolic, and inflammatory counterregulatory responses to hemorrhagic shock. Alcohol intoxication enhanced hemodynamic instability during blood loss and impaired the recovery of mean arterial blood pressure during fluid resuscitation. Activation of neuroendocrine pathways involved in restoring hemodynamic stability was significantly attenuated in alcohol-intoxicated hemorrhaged animals. The hemodynamic and neuroendocrine impairment is associated with enhanced expression of lung and spleen tumor necrosis factor, and it suppressed circulating neutrophil function. In addition, neuroimmune regulation of cytokine production by spleen-derived macrophages obtained from alcohol-intoxicated hemorrhaged animals was impaired when examined in vitro. We hypothesize that impaired neuroendocrine activation contributes to hemodynamic instability, which, in turn, prolongs tissue hypoperfusion and enhances risk for tissue injury. Specifically, the early dysregulation in counterregulatory responses is hypothesized to affect host defense mechanisms during the recovery period. We examined host response to systemic (cecal ligation and puncture) and localized (pneumonia) infectious challenge in animals recovering from hemorrhage during acute alcohol intoxication. Increased morbidity and mortality from infection were observed in alcohol-intoxicated hemorrhaged animals. Our results indicate that alcohol-induced alterations in early hemodynamic and neuroimmune responses to shock have an impact on susceptibility to an infectious challenge during the early recovery period.     

A preliminary study of chemo- and cytokine responses in rabies vaccine recipients of intradermal and intramuscular regimens

Plasma from 10 patients who had received rabies vaccine either intradermally (ID) or intramuscularly (IM) was examined for 20 chemo- and cytokines. Plasma samples were withdrawn on days 0, 3 and 7 after vaccination. These chemo- and cytokines and sampling days were chosen based on data collected from a protein array analysis of 122 cytokines conducted on one recipient of vaccine administered IM and one recipient of vaccine administered ID. Although eotaxin, interleukin (IL)-5 in the ID and IL-1 beta in the IM group were the only chemo- and cytokines that reached statistical significance (p < 0.05), the overall trends may suggest bias on Th1 or Th2 according to vaccination routes. IL-1 alpha, -2, and -6, hemofiltrate cysteine–cysteine chemokine (HCC-4), glucocorticoid induced tumor necrosis factor receptor (GITR), tumor necrosis factor (TNF) related apoptosis inducing ligand-receptor (TRAIL-R3) had some degree of elevation in the ID group. TNF-alpha, gamma-interferon, granulocytes/macrophages – colony stimulating factor (GM-CSF), transforming growth factor (TGF)-beta, lymphotactin and pulmonary and activation-regulated chemokine (PARC) were elevated, although not to a significant level, in the IM group. IL-12, interferon-inducible T cell alpha chemoattractrant (I-TAC) and sertoli cell factor (SCF) were not significantly elevated in both groups whereas IL-4 and -10 were unchanged. Further studies are required to determine whether the presence of specific chemokines, such as eotaxin, is responsible for the production of high levels of rabies virus neutralizing antibody after administration of the dose-sparing ID regimen.     

THE EFFECT OF NALOXONE ON THE HEPATOCELLULAR REDOX STATE AND SERUM ETHANOL CONCENTRATIONS FOLLOWING ACUTE ETHANOL ADMINISTRATION

Naloxone hydrochloride (2.0 mg/kg) has been found to reversethe significant decreases in the hepatic cytosolic and mitochondria1[NAD⁺]/[NADH] ratios observed after acute ethanol administrationin rats. This correction of the ethanol-induced changes in thehepatocellular redox state by naloxone was, however, not aswiatedwith any lowering of serum ethanol concentrations or an observablereduction in the extent of intoxicatlon. Thls lack of antagonismof alcohol intoxication by naloxone was not affected by thefeeding status of the animals, the time point after naloxoneadministration at which serum ethanol concentration was determinedor the method used for ethanol analysis. Thus this study hasfailed to confirm that naloxone antagonises acute alcohol intoxication,in spite of 11s potent abllity to reverse the ethanol-inducedchanges in the hepatic redox state.     

Melatonin Prevents T Lymphocyte Infiltration to the Kidneys of Hypertensive Rats,Induced by a High-Salt Diet,by Preventing the Expression of CXCR3 Ligand Chemokines

In a previous study, we demonstrated that melatonin prevents kidney damage in a salt-induced hypertension model by decreasing oxidative stress. We hypothesized that this effect involves melatonin’s immunomodulatory properties. In vivo Study-Dahl salt-sensitive (DSS) rats were fed normal chow, a high-salt diet (HSD), or a HSD and melatonin (30 mg/kg/day) in their water for eight weeks. Kidneys were harvested for immediate lymphocyte isolation and characterization by Flow cytometry (CD3+CD4+ and CD3+CD8+) and for lymphocyte chemoattractant (mainly CXCL chemokines) gene expression studies. In vitro study-rat mesangial cells (RMC) were cultured in a high-salt medium without and with melatonin. A HSD was associated with significant renal infiltration of CD4+ and CD8+ T lymphocytes compared to control. Melatonin significantly reduced renal lymphocyte infiltration. A HSD significantly increased mRNA expression of CXCL chemokines. Adding melatonin to the HSD abolished this effect. Treating RMC cells with salt increased the expression of CXCL10 and CXCL11 but not CXCL9. Adding melatonin to the culture media prevented this increase. Treating HSD-fed rats with melatonin decreased renal lymphocyte chemoattractant mRNA expression and is associated with significantly reducing renal T lymphocyte infiltration. Salt may have a direct effect on chemokine-producing renal cells, which is blunted by melatonin treatment.