The effect of five antibacterial agents on the physiological levels of serum nitric oxide in mice

In addition to their action on microorganisms, antibacterial agents have been reported to affect host defense mechanisms. Nitric oxide (NO) that is produced by a number of cell types in the innate immune response is bactericidal, but when produced in excessive amounts it could be detrimental to the host. In this study, five antibacterial agents (gentamicin, tobramycin, imipenem, tigecycline, isoniazid) were compared with respect to their ability to affect NO production in mice. Groups of mice were injected with the different antibacterial agents, and at different time intervals post-injection serum NO levels were determined using the Griess reagent. All the antibacterial agents tested showed a significant effect in reducing NO levels in mice. It could be hypothesized that the excessive production of NO in infectious diseases is in most instances suppressed by the antibacterial agent(s) used.     

肝移植围术期血浆一氧化氮和一氧化氮合酶活性的变化及意义

目的：动态观察肝移植围术期血浆一氧化氮（NO）水平和一氧化氮合酶（NOS）活性的变化，并探讨其意义。 方法： 30例终末期肝病患者接受原位肝移植术。用放免法、比色法分别测定肝移植围术期5个时点血浆NO2-/NO3-水平和NOS活性，观察其动态变化。同步抽取桡动脉和肺动脉血做血气分析，记录不同时期的PO2、PCO2、SO2、Hb，根据肺内分流标准模型公式计算(Qs/Qt)。并监测围术期心输出量（CO）、心率（HR）、中心静脉压（CVP）、平均动脉压（MABP）、体循环阻力（SVR）。 结果： (1) 无肝前10 min NO2-/NO3-水平明显高于麻醉后术前。无肝期30 min NO2-/NO3-显著低于无肝前10 min。新肝期30 min NO2-/NO3-显著高于麻醉后术前、无肝期30 min。（2）TNOS活性各时点无显著差异。无肝前10 min、新肝30 min时iNOS活性明显高于麻醉后术前。与无肝30 min值比较，新肝期30 min iNOS活性显著升高。（3）MABP在开放下腔静脉后1 min明显下降，CO和CVP在无肝期下降，新肝期增高。SVR在无肝期增高，新肝期明显下降。（4）Qs/Qt在无肝期下降，新肝期30 min升高。 结论： 在肝移植围术期各个时段，NO水平及iNOS活性各不相同。高NO水平可能是新肝期低阻力、肺内分流增加的原因。     

Influence of nitric oxide agents in the rat amygdala on anxiogenic-like effect induced by histamine

Background/aims: Both histamine and nitric oxide (NO) may play a role in anxiety-like behavior. Within the brain, the amygdala is an important area involved in processing emotional responses such as anxiety. The aim of the present study was to assess whether the NO system in the basolateral amygdala (BLA) influences histamine-induced anxiety-like behavior in rats. Methods: Male Wistar rats weighing 200–220 g were used. Bilateral cannulae were implanted in the BLA place for microinjections of drugs and the elevated plus maze apparatus has been used to test parameters (%OAT, %OAE, locomotor activity) of anxiety-like behavior. Results: Intra-BLA administration of histamine (2.5 and 5 μg/rat) decreased %OAT [P < 0.001]. Histamine (5 μg/rat) also reduced %OAE [P < 0.05] but not locomotor activity. The results obtained may indicate an anxiolytic response for histamine. Furthermore, bilateral intra-BLA microinjections of different doses of l-arginine (l-arg), an NO precursor (0.5 and 1 μg/rat) increased %OAT [P < 0.01], %OAE [P < 0.01] and locomotor activity [P < 0.001] while NG-nitro-l-arg methylester (l-NAME), a potent inhibitor of NO-synthase (NOS; 0.025, 0.05 and 0.1 μg/rat) decreased %OAT [P < 0.05] and locomotor activity [P < 0.001] but not %OAE. The combination of l-arg (0.5 μg/rat) with histamine increased %OAE [P < 0.001] but had no effect on %OAT and locomotor activity. Finally, the combination of l-NAME (0.025 μg/rat) with histamine decreased %OAT [P < 0.001] and locomotor activity [P < 0.05] but increased %OAE. Conclusion: The results indicate a modulatory role for NO in BLA in the anxiogenic response of histamine in rats.     

柯萨奇B4病毒诱导的实验性糖尿病小鼠血清一氧化氮浓度的变化

目的:观察CB₄V诱导的实验性糖尿病小鼠血清NO浓度的变化以及在不同时期产生的IL-1水平。方法:建立CB₄V诱导的实验性糖尿病小鼠模型,分别在病毒感染后72h、1周、3周、6周、8周,用硝酸还原酶法测定血清NO^-₂/NO^-₃含量,同时测定经LPS诱导的巨噬细胞产生的IL-1水平。结果:(1)血清NO^-₂/NO^-₃浓度变化:对照组各时期血清NO^-₂/NO^-₃浓度无显著差异,模型组小鼠血清NO^-₂/NO^-₃浓度在CB₄V感染72h后显著增高(P＜0.01),在感染后1周达到高峰,6-8周时接近正常水平。(2)IL-1水平的测定:在CB₄V感染后72h,IL-1水平明显高于对照组(P＜0.01),1周达到高峰(P＜0.01),6周接近正常水平。在各时期NO^-₂/NO^-₃与IL-1均呈高度正相关。结论:NO可能参与CB₄V诱导的IDDM发生发展过程。     

The role of nitric oxide in the proconvulsant effect of delta-opioid agonist SNC80 in mice

The involvement of nitric oxide (NO) in modulation of seizure susceptibility by delta-opioid agonist (+)-4-((alpha R)-alpha-((2S, 5R)-4-allyl-2, 5-dimethyl-1-piperazinyl)-3-methoxybenzyl)-N, N-diethyl-benzamide (SNC80) was examined in mice. Systemic administration of SNC80 (0.1-5 mg/kg, intraperitoneally (i.p.)) decreased the threshold for clonic seizures induced by pentylenetetrazole. The non-specific NO synthase (NOS) inhibitor, N(G)-nitro-L-arginine methyl ester (3-20 mg/kg, i.p.), but not the specific inducible NOS inhibitor, aminoguanidine (50 and 100 mg/kg, i.p.) inhibited the proconvulsant effect of SNC80. On the other hand, NO substrate, L-arginine (30 and 60 mg/kg, i.p.) potentiated the proconvulsant effect of a lower dose of SNC80 (0.5 mg/kg). These results support the involvement of NO, produced by constitutive NOS, in the proconvulsant effect of the delta-opioid agonist.     

Effects of five different contrast agents on serum complement and calcium levels after excretory urography

The effects of five different radiocontrast media (RCM) molecules on the complement system were investigated in vivo in human patients undergoing excretory urography. Ioxitalamic, ioxaglic, Na-diatrizoic, Na-Mg diatrizoic acids, and iopamidol were randomly used in 61 patients. Proteins involved in classic or alternate pathway, RCM plasma concentration, total and ionized calcium levels, and osmolarity were analysed before (TO), 90 sec (T1), and 30 min (T2) after RCM injection. Proteins of the classic and alternate pathways of complement activation were significantly decreased at T1, at a range of 7% to 17%. However, these impairments were rapidly reversible, since no significant variations, as compared with TO values, were observed at T2, except after use of ioxaglic acid. A significant decrease in total serum calcium level from 91 to 83 mg/L was observed at T1 for all RCM tested. However, a tendency toward improvement at T2 was noted. Ionized calcium serum levels were also significantly decreased at T1, except when ioxaglic acid and iopamidol were used. These changes were reversible at T2 for all RCM except ioxitalamic acid. The magnitude of the variation of complement protein levels and of calcium levels observed in vivo was related to the nature of the molecule tested and was of a decreasing order after injection of ioxitalamic acid, Na-Mg diatrizoic acid, Na-diatrizoic acid, iopamidol, and ioxaglic acid. There was no modification of plasma osmolarity after RCM injection.     

增强型体外反搏对冠心病患者血清一氧化氮和丙二醛的影响

目的:探讨增强型体外反搏对冠心病患者血清一氧化氮(NO)和丙二醛(MDA)的影响.方法:采用硝酸盐还原酶法测定69例冠心患者(反搏组31例,药物组38例)和35名正常人血清中NO2-和NO3-的含量,以反映NO的浓度,同时检测血清中MDA的含量,观察冠心病患者增强型体外反搏过程中及反搏后血清NO和MDA的动态变化.结果:治疗前,反搏组和药物组冠心病患者血清NO含量(38.88±17.03) μmol/L,(40.78±7.38) μmol/L明显低于正常人水平(70.86±7.61) μmol/L,P＜0.05.经过3个疗程的增强型体外反搏治疗,患者血中NO含量明显增高(105.47±25.58) μmol/L,P＜0.05,对照组经过6周药物治疗,血中NO也有一定程度的增高(48.52±10.04) μmol/L,但仍低于正常水平.与此相反,治疗前反搏组和药物组冠心病患者血清MDA含量(5.74±0.53) nmol/L,(5.71±0.59) nmol/L明显高于正常人水平(3.87±0.65) nmol/L,P＜0.05.经过3个疗程的增强型体外反搏治疗,患者血中MDA含量明显降低(4.04±0.65) nmol/L,P＜0.05,但药物组经过6周药物治疗,血中MDA无明显变化(5.60±0.55) nmol/L.在增强型体外反搏过程中,随着疗程的增加,冠心病患者血清NO含量逐渐升高,而MDA浓度则逐渐降低.结论:提示增强型体外反搏可促进NO的释放,从而调整内皮功能,并降低MDA的产生,抑制脂质过氧化反应,为增强型体外反搏在临床上的应用提供新的理论依据.     

The effect of spermatic vessel ligation on testicular nitric oxide levels and germ cell-specific apoptosis in rat testis

Management of high testis may vary but the most popular method in surgical treatment is the Fowler-Stephens maneuver. The aim of the present study was to investigate the effects of spermatic vessel ligation on testicular nitric oxide (NO) levels, expression of inducible nitric oxide synthase (iNOS), and endothelial nitric oxide synthase (eNOS) and germ cell-specific apoptosis in both ipsilateral and contralateral testes in rats. Twenty-eight animals were randomly allocated into four groups (n=7 each). The spermatic vessels were ligated as a simulation of the Fowler-Stephens maneuver. The groups of animals were sacrificed at 2 h (group 1), 4 h (group 2) and 24 h (group 3) after ligation, respectively. Sham-operated animals served as controls (group 4). Biochemical assessment of testicular NO levels was performed by the Griess method. iNOS and eNOS expression and apoptosis were studied in ipsilateral and contralateral testes. Testicular NO levels at 24 h after the simulated Fowler-Stephens maneuver were found to be significantly increased in both ipsilateral and contralateral testes when compared with the sham-operated group. eNOS expression was clearly increased in ipsilateral testes, whereas moderate expression was detected in the contralateral seminiferous tubules at 24 h after ligation. Mild focal iNOS immunostaining was also observed in seminiferous tubules of the ipsilateral testis at 24 h after the simulated Fowler-Stephens maneuver. Apoptosis was dramatically increased in ipsilateral testes; however, it was only detected in single cells in the contralateral side at 24 h after ligation. In conclusion, the simulated Fowler-Stephens maneuver induces testicular nitric oxide synthesis and germ cell-specific apoptosis in the ipsilateral testis. These results suggest that high levels of NO induce apoptosis and may impair spermatogenesis thus explaining the unsuccessful outcome of the Fowler-Stephens maneuver.     

Combined effect of IL-17 and blockade of nitric oxide biosynthesis on haematopoiesis in mice

Aim: The study was undertaken to extend our investigation concerning both the in vivo activity of interleukin (IL)-17 and the specific role of nitric oxide (NO) in IL-17-induced effects in the process of haematopoiesis. Methods: CBA mice were simultaneously treated with IL-17 and/or nitric oxide synthase (NOS) inhibitor, l -NAME, for 5 days and changes within various haematopoietic cell lineages in bone marrow, spleen and peripheral blood were analysed. Results: Findings showed that administration of both IL-17 and l -NAME stimulated increase in net haematopoiesis in normal mice. IL-17-enhanced myelopoiesis was characterized by stimulation of both femoral and splenic haematopoietic progenitor cells and morphologically recognizable granulocytes. Additionally, IL-17 induced alterations in the frequency of erythroid progenitor cells in both bone marrow and spleen, accompanied with their mobilization to the peripheral blood. As a consequence of these changes in the erythroid cell compartments, significant reticulocytosis was observed, which evidenced that in IL-17-treated mice effective erythropoiesis occurred. Exposure of mice to NOS inhibitor also increased the number of both granulocyte-macrophage and erythroid progenitors in bone marrow and spleens, and these alterations were followed by the mobilization of erythroid progenitors and elevated content of reticulocytes in peripheral blood. The specific role of NO in IL-17-induced haematopoiesis was demonstrated only in the IL-17-reducing effect on bone marrow late stage erythroid progenitors, CFU-E. Conclusion: The results demonstrated the involvement of both IL-17 and NO in the regulation of haematopoietic cell activity in various haematopoietic compartments. They further suggest that IL-17 effects are differentially mediated depending on the haematopoietic microenvironments.     

Influence of toxoplasmosis on acetylcholinesterase activity,nitric oxide levels and cellular lesion on the brain of mice

The objective of this study was to investigate the activity of acetylcholinesterase (AChE), nitrite/nitrate (NO_x) levels, as well as the biomarkers of cellular damage in the brain of mice experimentally infected with Toxoplasma gondii. Sixty mice were divided into two experiments: in experiment I the mice were infected with T. gondii/RH strain, while in experiment II they were infected with T. gondii, strains VEG and ME-49. Our evaluations were carried out on brain homogenized samples, assessing the AChE and glutathione reductase (GR) activities, and NO_x, TBARS and AOPP levels in all the infected animals, compared with the control group. In both experiments, I and II, it was observed an increase in the activity of AChE and GR, as well as in the levels of NO_x in the brain of infected mice with T. gondii. TBARS levels were increased in mice infected with the three different strains, RH, ME-49, and VEG. AOPP concentration was increased only in mice infected with the RH strain. Animals infected with the strains VEG and ME-49 showed histological lesions, associated with the presence of the parasite in the brain. Therefore, the infection by T. gondii is able to interfere in cholinesterase activity and NO levels, in association with oxidative stress and histological lesion.     

Increased serum nitric oxide metabolites in dysglycaemia

Background: Nitric oxide plays an important role in hyperglycaemia-induced endothelial dysfunction.

Aim: To investigate the relationship between serum nitric oxide metabolite (NO_x) levels and fasting glucose in a population-based study.

Subjects and method: Serum concentration of NO_x was measured by the Griess method in 3505 participants, aged 20–94 years, selected from a population-based study.

Results: In men with impaired fasting glucose, each mmol/L increase in fasting serum glucose increased probability of serum NO_x levels higher than median (> 25 μM) by 3.05-times (OR = 3.05 [95% CI, 1.15–8.07], p = 0.025) in non-adjusted and 3.76-times (OR = 3.76 [95% CI, 1.34–10.53, p = 0.012) in multivariable-adjusted analyses, while no significant associations were found in women. A direct association between fasting glucose categories and NO_x values was found in men after multivariable adjustment (p = 0.006). Multivariable-adjusted serum NO_x was significantly (p = 0.008) higher in diabetic men [34.1 (29.5–39.6) μmol/L] compared to non-diabetic ones [29.7 (26.5–33.2) μmol/L].

Conclusion: The findings show increased serum NO_x levels in men, but not women, with impaired fasting glucose and diabetes in a population-based study.     

一氧化氮在巨噬细胞的细胞毒效应中的作用

目的:探讨一氧化氮(NO)对巨噬细胞细胞毒效应的影响。方法:将20只昆明种小鼠分为两组,一组皮下接种S180横纹肌肉瘤细胞,另一组作为正常对照组。分别取两组小鼠腹腔灌洗液中的巨噬细胞与K562肿瘤细胞共同培养,检测在培养液中加入左旋精氨酸(L-Arg)和G-单甲基左旋精氨酸(L-NAME)后巨噬细胞杀伤率的改变。结果:正常小鼠腹腔灌洗液中的巨噬细胞在L-Arg和L-NAME存在的情况下细胞毒效应没有改变;荷瘤小鼠腹腔灌洗液中的巨噬细胞在L-Arg组和空白组中的细胞毒效应明显增强。结论:NO是巨噬细胞细胞毒作用的一个效应分子。     

Potential physiological and pathophysiological roles of nitric oxide in the brain.

Nitric oxide (NO) is a free radical molecule which has been described to play a role as a messenger molecule in at least three systems: white blood cells, blood vessels and most recently in the nervous system. In the brain, NO is produced enzymatically in postsynaptic structures in response to activation of excitatory amino acid receptors. A major action of NO is to activate soluble guanylate cyclase and to raise cGMP level in target cells. The role of NO as a messenger in long-term potentiation and in long-term depression has been established and recent studies have directly implicated NO in neuronal damage associated with vascular strokes. Concerning the role of NO in the excitatory amino acid neurotoxicity, more studies will be necessary to elucidate the implication of NO mediating neuronal damage. Whatever the exact function of NO, it is sure that this substance play an important role in the brain and that pharmacological manipulations of NO pathway will constitute a novel approach for therapeutical applications in the future.     

Assessing the physiological concentration and targets of nitric oxide in brain tissue

Low nanomolar concentrations of nitric oxide activate guanylyl cyclase to produce cGMP, which has diverse physiological effects. Higher concentrations inhibit mitochondrial respiration at cytochrome c oxidase and this has been proposed to be important physiologically, increasing oxygen permeation into tissue (by reducing the oxygen use of cells near blood vessels), activating AMP kinase, and regulating the relationship between cerebral blood flow and oxygen use. It is unclear, however, whether nitric oxide can accumulate physiologically to concentrations at which inhibition of respiration occurs. In rat cerebellar slices, we activated nitric oxide production from each isoform of nitric oxide synthase. Only activation of inducible nitric oxide synthase, which is expressed pathologically, caused any significant inhibition of respiration. Modelling oxygen and nitric oxide concentrations predicted that, in vivo, physiological nitric oxide levels are too low to affect respiration. Even pathologically, the nitric oxide concentration may only rise to 2.5 n m , producing a 1.5% inhibition of respiration. Thus, under physiological conditions, nitric oxide signals do not inhibit respiration but are well-tuned to the dynamic range of guanylyl cyclase activation.