抑癌基因PTEN与iNOS在胶质瘤中表达及意义

目的探讨抑癌基因PTEN和诱导型一氧化氮合酶(iNOS)在胶质瘤组织中表达意义及两者与胶质瘤侵袭性的关系。方法采用LSAB免疫组织化学法检测56例胶质瘤中PTEN、iNOS蛋白的表达,并分析两者与胶质瘤病理级别和侵袭性的关系。结果PTEN在胶质瘤Ⅰ、Ⅱ、Ⅲ、Ⅳ级中阳性率分别为91．7％、75％、53．3％、15．4％,PTEN表达阳性率随病理分级升高而降低(P＜0．01)。而iNOS表达阳性率分别为50％、38．1％、73．3％、76．9％;iNOS表达水平与PTEN表达水平呈负相关(P＜0．05)。结论PTEN和iNOS的表达一定程度反映胶质瘤的恶性度和侵袭性强弱;PTEN缺失可引起iNOS表达增加,在胶质瘤发生、发展过程中发挥重要作用。     

A functional variant of the iNOS gene flanking region is associated with LAD coronary artery disease: an autopsy study

Background Recent studies using reporter gene constructs have indicated significant differences in the promoter activity of inducible nitric oxide synthase (iNOS) gene variants. Although the exact role of iNOS in atherogenesis is unclear, it is possible that this variation site may influence the extent of coronary artery disease (CAD). Methods We amplified these (AAAT) repeat variants from the NOS2A gene (denoted iNOS R4 and iNOS R5) from 325 Finnish men included in the Helsinki Sudden Death Study, and studied their association with indices of stenosis and atherosclerosis of the left anterior descending artery (LAD), right coronary artery (RCA) and left circumflex artery (LCX). In order to understand the effect of iNOS genotype on different stages of CAD, our study population was divided into age groups. Results In the LAD, the progression of atherosclerosis seemed to be more pronounced in the 4/5 genotype carriers than in those with the 4/4 genotype when the different age groups were compared. More specifically, statistically significant differences between the genotypes were found in the subgroup of men aged > 55 years. In this group, men carrying the rare R4/5 genotype presented higher mean values of stenosis percentages (55% vs. 42%, P = 0·008), larger areas of fatty streaks (10·4% vs. 5·9%; P = 0·01) and complicated lesions (3·5% vs. 1·3%; P = 0·001) compared with the R4/4 carriers. No significant association of iNOS genotypes with stenosis and atherosclerosis of RCA and LCX was found. Conclusions It appears unlikely the R4/5 genotype plays a major role in the pathogenesis of CAD, as it was not associated with stenosis and atherosclerosis in RCA and LCX. However this genotype may have some role in more pronounced CAD, as seen in the LAD.     

Pathogenic molecular mechanisms in an animal model of fulminant hepatic failure: rabbit hemorrhagic viral disease

In this study we sought to determine whether molecular mechanisms involved in the pathogenesis of fulminant hepatic failure are present in rabbits experimentally infected with rabbit hemorrhagic disease virus (RHDV). The activities of aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase, as well as bilirubin concentration, were found to be significantly increased 36 hours after infection. Infected animals also demonstrated significant decreases in factor VII activity, in the Fischer index, and in the deterioration of prothrombin time. The concentration of reduced glutathione was significantly decreased 36 hours after infection, and we noted a marked increase in the ratio of oxidized to reduced glutathione. Infected animals showed progressive decreases in liver activity of the antioxidant enzyme superoxide dismutase. Expression of hepatocyte growth factor and c-met was found to be progressively reduced from 24 hours after infection, during which time we detected no modification in messenger RNA (mRNA) levels of transforming growth factor (TGF)-alpha. TFG-beta 1 was overexpressed 24 and 36 hours after infection, and 36 hours after infection we detected a significant increase in TNF-alpha mRNA levels. Experimental RHDV infection also induced marked activation of nuclear factor-kappaB and a significant increase in inducible nitric oxide synthase mRNA levels from 24 hours after infection. Data obtained from this animal model support its usefulness in the investigation of potential novel therapeutical modalities aimed at neutralizing reactive oxygen species and hepatocyte growth inhibitors or enhancing hepatocyte responsiveness to mitogens.     

Ethanol Upregulates iNOS Expression in Colon Through Activation of Nuclear Factor-kappa B in Rats

Background:  Alcohol inhibits colonic motility but the mechanism is unknown. The goal of this study was to test the possibility that nuclear factor-kappa B (NF-κB) is involved in the upregulation of inducible nitric oxide synthase (iNOS) expression induced by ethanol in colon.
Methods:  The isometric contraction of longitudinal muscle strips of proximal colon (LP) was monitored by polygraph. Western blot analysis was used to measure the amount of iNOS and I-κB in the cytoplasm and P65 in the nucleus. Immunohistochemistry was applied to locate iNOS in colon.
Results:  Ethanol (87mM) inhibited the contraction of LP. Pretreatment of S-methylisothioure (SMT) (1 mM), a specific iNOS inhibitor, Pyrrolidine dithiocarbamate (PDTC) (10 mM) and BAY11-7082(10 mM), specific inhibitors of NF-κB significantly reversed the inhibitory effect of ethanol on LP contraction. Ethanol increased the amount of iNOS and content of NO in colon, and these effects were attenuated by pretreatment of PDTC. Following ethanol administration, the amount of I-κB in the cytoplasm decreased, but that of P65, the subunit of NF-κB in the nucleus, increased. The iNOS was located in the cell body of myenteric plexus in colon.
Conclusion:  Ethanol inhibited the contraction of LP in colon mainly through activation of NF-κB, the subsequent upregulation of iNOS expression and increase of NO release in myenteric plexus.     

S-甲基异硫脲对大鼠门脉高压症食管静脉曲张的影响

目的观察诱导型一氧化氮合酶抑制剂SMT对大鼠门脉高压症食管静脉曲张的影响。方法健康雄性SD大鼠60只随机分为5组,假手术组、模型组、低剂量组、中剂量组和高剂量组。假手术组仅分离门静脉、左肾上腺静脉关腹,其余组门脉缩窄两步法加左肾上腺静脉结扎,建立门脉高压症食管静脉曲张模型。假手术组与模型组手术后给予腹腔注射生理盐水,其余3组手术后给予腹腔注射不同浓度SMT。手术后21 d,检测大鼠门脉血中TNOS、iNOS的活性及NO的浓度,免疫组化CD34标记食管血管内皮,测量每组大鼠食管横切面黏膜下血管的数目、面积。结果模型组大鼠门脉血中TNOS活性与iNOS活性以及NO浓度和食管黏膜下血管数目,血管平均截面积,血管总面积均较假手术组显著升高(P0.01)。中、高剂量组大鼠门脉血中TNOS活性与iNOS活性以及NO浓度和食管黏膜下血管的数目、血管平均面积、血管总面积较模型组均显著下调(P≤0.01)。结论大鼠门脉高压食管静脉曲张的发病机制中有NO参与,门脉缩窄型门脉高压食管静脉曲张病中NO主要由iNOS生成,SMT对大鼠门脉高压食管静脉曲张可能具有一定保护作用。     

电针抑制SD大鼠骨性关节炎COX2、iNOS、NO表达的实验研究

目的探讨电针对SD大鼠骨性关节炎模型血液及关节液中COX2、iNOS、NO表达的影响。方法成年SD大鼠180只,抽签法随机分为正常组、实验组,实验组采用4%木瓜蛋白酶双膝关节腔注射复制骨性关节炎模型,抽签法随机分为模型组、对照组、实验1组、实验2组、实验3组,对照组采用关节腔注射透明质酸钠,实验组采用电针干预,检测关节液中COX2、iNOS、NO含量,光学显微镜观察关节软骨的形态结构。结果血液及关节液中COX2、iNOS、NO,各实验组均高于正常组(P<0.05,P<0.01),对照组、实验2组、实验3组明显低于模型组(P<0.05,P<0.01);关节软骨改变的分数,各实验组均高于正常组(P<0.01),对照组、实验2组、实验3组明显低于模型组(P<0.01)。结论电针能有效抑制关节液中COX2、iNOS、NO表达,延缓关节软骨的退变。     

HWTX-I对运动性骨关节损伤大鼠关节软骨中iNOS表达及血清NO含量的影响

目的:观察虎纹蜘蛛毒素(HWTX-I)对运动性骨关节损伤大鼠软骨诱导型一氧化氮合成酶(iNOS)的表达及血清中一氧化氮(NO)含量的影响,探讨HWTX-I对慢性运动性骨关节损伤的保护作用机制,为其临床应用提供理论和实验依据。方法:雄性SD大鼠30只,采用改良Hulth模型结合间歇性中低强度运动建立大鼠运动磨损性骨关节病理模型。随机分成3组:非用药组、HWTX-I用药组和布洛芬用药组。对各组大鼠膝关节软骨进行显微结构形态学观察,采用免疫组织化学和图像分析系统检测iNOS水平的差异表达,分光光度法测定血清中NO含量。结果:3组iNOS的表达强度相比较,HWTX-I用药组明显低于非用药组和布洛芬用药组;HWTX-I用药组血清中NO的含量亦明显低于非用药组和布洛芬用药组。结论:INOS、NO在运动性骨关节损伤的病理进程中具有重要作用,HWTX-I可通过下调其在关节软骨的表达和血清中的含量,对大鼠运动性骨关节损伤关节有一定的抗损伤保护作用。     

Antimicrobial mechanisms of fish leukocytes

Early activation and coordination of innate defenses are critical for effective responses against infiltrating pathogens. Rapid engagement of immune cells provides a critical first line of defense soon after pathogen infiltration. Activation leads to a well-orchestrated set of events that sees the induction and regulation of intracellular and extracellular antimicrobial defenses. An array of regulatory mediators, highly toxic soluble molecules, degradative enzymes and antimicrobial peptides provides maximal protection against a wide range of pathogens while limiting endogenous damage to host tissues. In this review we highlight recent advances in our understanding of innate cellular antimicrobial responses of teleost fish and discuss their implications to cell survival, immunomodulation and death. The evolutionary conservation of these responses is a testament to their effectiveness against pathogen infiltration and their commitment to effective maintenance of host homeostasis. Importantly, recent developments in teleost fish systems have identified novel host defense strategies that may be unique to this lower vertebrate group or may point to previously unknown innate mechanisms that also play a significant role in higher vertebrate host immunity.     

TNFRp55 modulates IL-6 and nitric oxide responses following Yersinia lipopolysaccharide stimulation in peritoneal macrophages

While cytokines are major regulators of macrophage activation following host-pathogen interactions, they also act to limit inflammation to avoid tissue damage. In previous studies we reported the development of progressive Yersinia enterocolitica-induced reactive arthritis (ReA) in mice lacking the tumor necrosis factor receptor p55 (TNFRp55). In this work, we analyzed the response of TNFRp55^−/− macrophages to Y. enterocolitica antigens. We found higher concentration of nitric oxide (NO) in TNFRp55^−/− compared to wild-type macrophages in response to heat-killed Yersinia (HKY) and Yersinia outer membranes (OM). Moreover, Toll-like receptor (TLR)4 expression was increased in OM-stimulated TNFRp55^−/− versus wild-type (WT) macrophages. Accordingly, NO production was inhibited in TLR4-deficient macrophages following stimulation with OM, suggesting that LPS may function as a major OM component implicated in these responses. Thus, augmented NO production together with enhanced expression of inducible nitric oxide synthase (iNOS) and higher IL-6 production, may provide a pro-inflammatory setting in Yersinia LPS-stimulated TNFRp55^−/− macrophages. Augmented synthesis of NO and IL-6 was prevented by treatment with Polymyxin B, or by exposure to a specific NF-κB p65 oligonucleotide antisense, indicating the involvement of TLR4-mediated NF-κB activation in the unleashed pro-inflammatory response triggered by TNFRp55 deficiency. Thus, TNFRp55 modulates macrophage functions in response to Yersinia LPS stimulation through mechanisms involving NO, IL-6 and NF-κB pathways, suggesting an essential regulatory role of TNF via TNFRp55 signaling.