过氧亚硝基阴离子的研究进展

过氧亚硝基阴离子(peroxynitrite anion, ONOO-)是一氧化氮(NO)和氧自由基(O(-·)2)结合生成的.它可能是NO产生病理损伤作用的重要环节.它在休克、缺血-再灌注损伤、败血症、胰岛素依赖性糖尿病、动脉硬化及感染炎症等疾病中的作用已愈来愈受到重视.加强对ONOO-生成途径和NO、O(-·)2与ONOO-的相互作用的基础研究,以及ONOO-的病理生理作用的研究,特别是开展针对抗ONOO-损伤作用和有效清除体内ONOO-的新药研制,不仅有助于揭示NO的细胞毒作用的分子机制,还有助于为治疗某些临床危征提供启示性思路.     

过氧亚硝酸根与细胞信号转导

生物系统中产生的过氧亚硝酸根(peroxynitrite,ONOO-)具有强氧化性,能够损伤多种生物大分子,产生细胞毒性。细胞通过激活信号通路产生应激反应,其中包括蛋白质酪氨酸激酶(PTK)依赖的多种路径,而ONOO-通过硝化或氧化作用调节酪氨酸的磷酸化。酪氨酸残基的硝化能直接影响酪氨酸的磷酸化,而磷酸酶的氧化将导致酪氨酸磷酸化/去磷酸化平衡的改变,ONOO-激活细胞信号转导通路的作用机制对认识其生理病理功能具有重要意义。     

过氧亚硝酸阴离子通过鸟苷酸环化酶途径抑制钠电流影响海马神经元兴奋性

过氧亚硝酸阴离子(ONOO-)是一种性质活泼的自由基,可引起强的氧化性损伤,介导了一氧化氮(NO)的大部分毒性作用.应用全细胞膜片钳技术,探讨ONOO-对脑片海马神经元电压门控钠通道电流(Ina)和神经元兴奋性的影响.结果表明,ONOO-供体SIN-1(10,500,2000 μmol/L)可浓度依赖性抑制Ina电流峰值.SIN-1与ONOO-清除剂尿酸共处理,并不影响Lna.500 μmol/L的SIN-1可使Ina的,Ⅰ-Ⅴ曲线上移,并可抑制其失活后恢复过程,但对Ina的激活和失活过程无影响.SIN-1还可抑制动作电位发放频率和幅值.脑片预处理腺苷酸环化酶(adenylate cyclase,AC)抑制剂MDL-12,330A(25 μmol/L)和NEM(50μmol/L)对SIN-1的作用无影响.然而,预处理鸟苷酸环化酶(CG)抑制剂ODQ可抑制SIN-1对Ina的作用.以上结果提示,ONOO-通过cGMP-Ina-AP信号级联系统作用于海马神经元,与PKA和蛋白巯基亚硝化途径无关,这可能是ONOO-神经毒性的机制之一.     

葛根素对糖尿病致肺损伤的保护作用及其机制的研究

目的:探讨糖尿病对肺脏损伤及葛根素对肺组织影响的可能机制。方法:腹腔注射链脲佐菌素(STZ)建立大鼠糖尿病(DM)模型,SD大鼠随机分为对照组(C组)、糖尿病组(DM组)、糖尿病 葛根素组(DM Pur组)。检测注药前及模型成立后第20d、40d、60d的血糖及体重的改变。检测肺组织中一氧化氮(NO)和丙二醛(MDA)的含量、超氧化物歧化酶(SOD)活性。结合光镜、电镜、免疫组织化学染色方法综合评价。结果:①DM组NO、MDA高于C组(P<0.01),SOD活性低于C组(P<0.01),DM Pur组NO含量明显低于DM组(P<0.01),MDA含量40d开始显著降低(P<0.01),SOD活性高于DM组(P<0.01)。②光镜下见肺泡隔增厚,炎性细胞浸润;电镜下见Ⅱ型肺泡上皮细胞微绒毛数量明显减少,嗜锇性板层小体数量明显减少,细胞间质胶原纤维增生,葛根素可减轻肺组织上述病理性改变。③免疫组织化学染色结果:DM组细胞胞质中可见ONOO-特征性代表物硝基酪氨酸(ni-trotyrosine,NT)黄染阳性信号表达,且较对照组略为增强,DM Pur组黄染信号较DM组略为减弱。结论:①DM时可发生肺组织损伤,可能与长期高血糖诱导产生大量自由基有关。②NO/ONOO-通路是DM造成肺组织细胞损伤的机制之一。③初步证实葛根素能在一定程度上抑制高血糖诱导肺组织中自由基的过量生成,降低肺组织中的ONOO-的过度表达,这可能是其抗DM时肺组织损伤的作用机制之一。     

温度、pH及CO2对白藜芦醇与过氧亚硝基相互作用的影响

白藜芦醇(Resveratrol,Res)是植物在遇到紫外线照射、真菌感染等不利条件下自然产生的抗毒素,存在于多种植物中,具有明显的消炎、抗癌、抗血栓等作用。本文利用紫外-可见光谱法研究了Res与过氧亚硝基阴离子(Peroxynitrite anion,ONOO-)的相互作用,提出了反应机理。研究了温度、pH及CO2对Res与ONOO-反应的影响,结果表明低温、偏碱性pH有利于反应的进行;CO2存在时Res仍能与ONOO-反应,但反应机理与前面不同。     

自组装Trolox-壳聚糖纳米颗粒对CoCl2诱导的氧化应激损伤中PC12细胞的保护效果研究

以自组装方法制备了Trolox(6-Hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic Acid)-壳聚糖纳米颗粒,通过形态观察、MTT、MDA和活性氧荧光检测实验,研究了该纳米抗氧化剂对CoCl2诱导的氧化应激损伤中PC12细胞的保护效果。结果表明,与Trolox单体相比,纳米抗氧化剂能够更加有效地保护细胞形态、显著提高细胞活性和减轻细胞脂质过氧化损伤、高效地淬灭活性氧自由基。此外,通过荧光标记法还证明了PC12细胞能够吞噬该纳米抗氧化剂颗粒。综合实验结果认为,该纳米抗氧化剂可高效地保护PC12细胞缺氧引发的氧化损伤,这为纳米技术进一步应用于神经系统中缺氧相关疾病的抗氧化应激治疗提供了新的实验依据。     

Potential of peroxynitrite to promote the conversion of oxyhemoglobin to methemoglobin

Superoxide anion and NO can react to form the highly oxidizing species peroxynitrite (ONOO-)which can react directly with hemoglobin (Hb) even in the presence of physiological concentration CO:. Thisresearch was to determine the ONOO--mediated oxidation damage to the heme of oxyhemoglobin (oxyHb)under conditions expected in blood. Results showed that 8-10 mol ONOO- was needed to quickly andcompletely convert 1 mol oxyHb to methemoglobin (metHb). ONOO- (20-140 μM) caused raoid andextensive formation of metHb from oxyHb (50 μM) mainly occurring within first 5-20 min of incubation.The conversion efficiency reached 16%, 48%, 60%, 79% and 88% output of metHb after 90 min ofincubation at 0, 20, 40, 100, and 140 μM ONOO- respectively. 1 mM CO2 caused a small decrease in theability of ONOO- to oxidize oxyHb, and ONOO--promoted conversion of oxyHb to metHb increased whenpH decreased from 8.0 to 6.0. Relatively lower temperature in blood condition will inhibit this reaction insome degree. We postulate that ONOO- can mediate oxidation damage to the heme, and cause heme lossfrom the hydrophobic cavity of Hb when its concentration exceeded 90 μM. These results indicated thatONOO- could convert oxyHb to metHb under the conditions expected in blood, and this reaction wasregulated by CO2 concentration, reaction time, temperature and pH value.     

蛋白和抗氧化剂对离心运动后肌肉功能和疼痛的影响

大量研究证实补充蛋白质或抗氧化剂均可有效提高机体的运动能力,然而,蛋白质和抗氧化剂联用的效果尚不清楚。本研究将60只SD大鼠随机分为4组,安静组(CG)、运动组(EG)、蛋白组(PG)和蛋白+抗氧化剂组(PAG),每组15只。PG组大鼠按照0.5 g/kg的剂量灌胃乳清蛋白溶液,PAG组大鼠按照0.5 g/kg的剂量灌胃乳清蛋白和抗氧化剂(富含花青素的浆果提取物)溶液。CG和EG组大鼠灌胃等体积的蒸馏水,共灌胃1周。然后,EG、PG和PAG组大鼠进行90 min的离心运动。采用机械缩足阈值来反映各组大鼠离心运动后的肌肉酸痛程度,研究显示,离心运动48 h后,PG组和PAG组大鼠的机械缩足阈值明显高于EG组,并且PG组和PAG组高于PG组。多项研究均显示,IL-6、IL-1β、MG53和MyoD参与肌肉的损伤及修复过程。本研究检测了上述因子的变化情况,发现大鼠在离心运动48 h后,后胫骨前肌组织中IL-6、IL-1β、MG53和MyoD的蛋白表达水平均显著升高,而蛋白+抗氧化剂可显著抑制上述指标的升高。苏木精伊红(HE)染色显示,离心运动48 h后,运动组大鼠的肌纤维受损程度达39.43%,显著高于蛋白组(23.54%)和蛋白+抗氧化剂组(8.42%)。此外,蛋白和抗氧化剂可显著抑制离心运动诱导的血清肌酸激酶的升高,并提高超氧化物歧化酶的活性。本研究证实蛋白联合抗氧化剂可有效减少离心运动引起的肌肉损伤、抑制机体的炎症反应并降低肌肉酸痛程度。     

抗氧化剂对DNA损伤的保护作用机制的研究

在ＣｕＳＯ４－Ｐｈｅｎ－ＶＣ－Ｈ２Ｏ２－ＤＮＡ化学发光体系中测量了若干抗氧化剂对ＤＮＡ损伤的保护作用。实验发现抗氧化剂对ＤＮＡ有三种保护作用机制：Ⅰ,延迟ＤＮＡ损伤;Ⅱ,抑制ＤＮＡ损伤;Ⅲ,延迟兼抑制ＤＮＡ损伤。不同抗氧化剂有不同的作用机制。本文认为延迟损伤作用代表抗氧化剂的断链性作用,而抑制损伤作用代表抗氧化剂的预防性作用,从而为区别分析抗氧化剂的预防性作用和断链性作用提供了一个简便直观的方法     

过氧亚硝酸阴离子通过鸟苷酸环化酶途径抑制钠电流影响海马神经元兴奋性

过氧亚硝酸阴离子（ONOO-）是一种性质活泼的自由基,可引起强的氧化性损伤,介导了一氧化氮（NO）的大部分毒性作用．应用全细胞膜片钳技术,探讨ONOO-对脑片海马神经元电压门控钠通道电流（INa）和神经元兴奋性的影响．结果表明,ONOO-供体SIN-1（10,500,2000μmol／L）可浓度依赖性抑制INa电流峰值．SIN-1与ONOO-清除剂尿酸共处理,并不影响INa．500μmol／L的SIN-1可使INa的I-V曲线上移,并可抑制其失活后恢复过程,但对INa的激活和失活过程无影响．SIN-1还可抑制动作电位发放频率和幅值．脑片预处理腺苷酸环化酶（adenylate cyclase,AC）抑制剂MDL-12,330A（25μmol／L）和NEM（50μmol／L）对SIN-1的作用无影响．然而,预处理鸟苷酸环化酶（CG）抑制剂ODQ可抑制SIN-1对INa的作用．以上结果提示,ONOO-通过cGMP-INa-AP信号级联系统作用于海马神经元,与PKA和蛋白巯基亚硝化途径无关,这可能是ONOO-神经毒性的机制之一．     

Protective effects of resveratrol against oxidative/nitrative modifications of plasma proteins and lipids exposed to peroxynitrite

The protective effects of resveratrol (3, 4', 5-trihydroxystilbene; present naturally in different plants) against the oxidative/nitrative damage of human plasma proteins induced by peroxynitrite (ONOO-) were studied and compared with those of deferoxamine (DFO; a natural siderophore isolated from Streptomyces pilosus), which is a typical and well-known antioxidant. We also studied the effect of ONOO- on plasma lipid peroxidation and the role of tested antioxidants in this process. ONOO- at the used concentrations (0.01-1 mM) showed toxicity to human plasma components. Exposure of plasma to ONOO- (0.1 mM) resulted in an increase of the level of carbonyl groups and nitrotyrosine residues in plasma proteins (approximately 4-fold and 76-fold, respectively) and in a distinct augmentation of lipid peroxidation (approximately 2-fold). In the presence of 0.1-mM resveratrol, a distinct decrease of carbonyl group formation and tyrosine nitration in plasma proteins caused by 0.1-mM ONOO- was observed (by approximately 70% and 65%, respectively). Addition of 0.1-mM DFO to plasma also distinctly reduced the level of carbonyl groups and nitrotyrosines caused by 0.1-mM ONOO- (by approximately 50% and 60%, respectively). Moreover, these antioxidants also inhibited plasma lipid peroxidation induced by ONOO- (0.1 mM). The obtained results indicate that in vitro resveratrol, like well-known antioxidant DFO, has inhibitory effects on ONOO- -mediated oxidation of proteins and lipids in human plasma.     

Inhibitory effects of water-soluble cationic manganese porphyrins on peroxynitrite-induced SOS response in Salmonella typhimurium TA4107/pSK1002

We have investigated the protective effects of water-soluble cationic Mn(III) porphyrins against peroxynitrite (ONOO-)-induced DNA damage in the cells of Salmonella typhimurium TA4107/pSK1002 and lipid peroxidation of red blood cell membranes. Mn(III) tetrakis (N-methylpyridinium-4-yl) porphine (TMPyP) and the brominated form, Mn(III) octabromo-tetrakis (N-methylpyridinium-4-yl) porphine (OBTMPyP) effectively reduced the damage and peroxidation induced by N-morpholino sydnonimine (SIN-1), which gradually generates ONOO- from O2*- and *NO produced through hydrolysis. Mn(III)OBTMPyP became 10-fold more active than the non-brominated form. In the presence of authentic ONOO-, the Mn(III) porphyrins were ineffective against damage and strongly enhanced lipid peroxidation, while the coexistence of ascorbic acid inhibited peroxidation. Using a diode array spectrophotometry, the reactions of Mn(III)TMPyP with authentic ONOO- and SIN-1 were measured. Mn(III)TMPyP is known to be catalytic for ONOO- decomposition in the presence of antioxidants. OxoMn(IV)TMPyP with SIN-1 was rapidly reduced back to Mn(III) without adding any oxidants. Further, in the SIN-1 system, the concentration of NO2- and NO3- were colorimetrically determined by Griess reaction based on the two-step diazotization. NO2- increased by addition of Mn(III) porphyrin and the ratio of NO2- to NO3- was 4-7 times higher than that (1.05) of SIN-1 alone. This result suggests that O2*- from SIN-1 acts as a reductant and *NO cogenerated is oxidized to NO2-, a primarily decomposition product of *NO. Under the pathological conditions where biological antioxidants are depleted and ONOO- and O2*- are extensively generated, the Mn(III) porphyrins will effectively cycle ONOO- decomposition using O2*-.     

Peroxynitrite-mediated alpha-tocopherol oxidation in low-density lipoprotein: a mechanistic approach

Previous reports proposed that peroxynitrite (ONOO-) oxidizes alpha-tocopherol (alpha-TOH) through a two-electron concerted mechanism. In contrast, ONOO- oxidizes phenols via free radicals arising from peroxo bond homolysis. To understand the kinetics and mechanism of alpha-TOH and gamma-tocopherol (gamma-TOH) oxidation in low-density lipoprotein (LDL) (direct vs. radical), we exposed LDL to ONOO- added as a bolus or an infusion. Nitric oxide (.NO), ascorbate and CO2 were used as key biologically relevant modulators of ONOO- reactivity. Although approximately 80% alpha-TOH and gamma-TOH depletion occurred within 5 min of incubation of 0.8 microM LDL with a 60 microM bolus of ONOO-, an equimolar infusion of ONOO- over 60 min caused total consumption of both antioxidants. gamma-Tocopherol was preserved relative to alpha-TOH, probably due to gamma-tocopheroxyl radical recycling by alpha-TOH. alpha-TOH oxidation in LDL was first order in ONOO- with approximately 12% of ONOO- maximally available. Physiological concentrations of.NO and ascorbate spared both alpha-TOH and gamma-TOH through independent and additive mechanisms. High concentrations of.NO and ascorbate abolished alpha-TOH and gamma-TOH oxidation. Nitric oxide protection was more efficient for alpha-TOH in LDL than for ascorbate in solution, evidencing the kinetically highly favored reaction of lipid peroxyl radicals with.NO than with alpha-TOH as assessed by computer-assisted simulations. In addition, CO2 (1.2 mM) inhibited both alpha-TOH and lipid oxidation. These results demonstrate that ONOO- induces alpha-TOH oxidation in LDL through a one-electron free radical mechanism; thus the inhibitory actions of.NO and ascorbate may determine low alpha-tocopheryl quinone accumulation in tissues despite increased ONOO- generation.     

Role of Ca2+-dependent metalloprotease-2 in stimulating Ca2+ ATPase activity under peroxynitrite treatment in bovine pulmonary artery smooth muscle membrane

We have determined effect of the oxidant peroxynitrite (ONOO-) on Ca2+-dependent matrix metalloprotease-2 (MMP-2) activity and the role of the protease on Ca2+ ATPase activity in bovine pulmonary vascular smooth muscle plasma membrane under ONOO- -triggered conditions. The smooth muscle plasma membrane possesses a 72-kDa protease activity in a gelatin-containing zymogram. The 72-kDa protease activity has been found to be inhibited by tissue inhibitor of metalloprotease-2 (TIMP-2), indicating that the protease is the matrix metalloprotease-2 (MMP-2). Treatment of the membrane suspension with ONOO- caused stimulation of the MMP-2 activity (as evidenced by 14C-gelatin degradation) and also increased Ca2+ ATPase activity. The ONOO- -triggered protease activity and the Ca2+ ATPase activity were found to be inhibited by the antioxidants: vitamin E, thiourea, and mannitol. Pretreatment with catalase and superoxide dismutase did not significantly alter ONOO- -stimulated MMP-2 activity and Ca2+ATPase activity, indicating that peroxide and superoxide are not present in appreciable amount in ONOO-. Under both basal and ONOO- triggered conditions, the MMP-2 activity and the Ca2+ ATPase activity were also inhibited by EGTA, 1:10-phenanthroline, and TIMP-2. However, the ONOO- -stimulated MMP-2 activity and the Ca2+ ATPase activity were found to be insensitive to phenylmethylsulfonylfluoride, Bowman-Birk inhibitor, chymostatin, leupeptin, antipain, N-ethylmaleimide, and pepstatin. These results suggest that ONOO- caused stimulation of MMP-2 activity and that the increased MMP-2 activity subsequently played a pivotal role in stimulating Ca2+ ATPase activity in bovine pulmonary vascular smooth muscle plasma membrane.     

Peroxynitrite and protein tyrosine nitration of prostacyclin synthase

When working on the regulation of prostacyclin synthase (PGIS), we found that PGIS was selectively inhibited by peroxynitrite (ONOO-), a potent oxidant formed by the combination of superoxide anion and nitric oxide (NO) at a rate of diffusion-controlled. None of the cellular antioxidants studied (i.e. GSH, Vitamins C and E, and others) prevented the inhibition of ONOO- on PGIS. This unexpected behavior was explained by a catalytic reaction of the iron-thiolate center of PGIS with ONOO- anion. In contrast, ONOO- activated both thromboxane A2-synthase and cyclooxygenases. In addition, we demonstrated that sub-micromolar levels of ONOO- inhibited PGI2-dependent vasorelaxation and triggered a PGH2-dependent vasospasm, indicating that ONOO- increased PGH2 formation as a consequence of PGIS nitration. We have subsequently demonstrated that endogenous ONOO- caused PGIS nitration and TxA2 activation in several diseased conditions such as atherosclerotic vessels, hypoxia-reperfusion injury, cytokines-treated cells, diabetes, as well as hypertension. Since NO is produced physiologically it seems that excessive formation of superoxide not only eliminates the vasodilatory, growth-inhibiting, anti-thrombotic and anti-adhesive effects of NO and PGI2 but also allows and promotes an action of the potent vasoconstrictor, prothrombotic agent, growth promoter, and leukocyte adherer, PGH2. We conclude that the nitration of PGIS nitration might be a new pathogenic mechanism for superoxide-induced endothelium dysfunction often observed in vascular diseases such as atherosclerosis, hypertension, ischemia, endotoxic shock, and diabetes.     

Relationship between the action of reactive oxygen and nitrogen species on bilayer membranes and antioxidants

Membrane lipid peroxidation (LPO) induced by hydroxyl (*OH) and ascorbyl (*Asc) radicals and by peroxynitrite (ONOO-) was investigated in asolectin (ASO), egg phosphatidylcholine (PC) and PC/phosphatidic acid mixtures (PC:PA) liposomes and rat liver microsomes (MC). Enthalpy variation (DeltaH) of PC:PA at different molar ratios were obtained by differential scanning calorimetry. It was also evaluated the LPO inhibition by quercetin, melatonin and Vitamin B6. The oxidant effect power follows the order *OH approximately *Asc > ONOO- on PC and MC; whilst on ASO liposomes, it follows *Asc > *OH approximately ONOO-. Increasing amounts of PA in PC liposomes resulted in lower levels of LPO. The DeltaH values indicate a more ordered membrane arrangement as a function of PA amount. The results were discussed in order to provide a complete view involving the influence of membranes, oxidants and antioxidants intrinsic behavior on the LPO dynamics.     

Antioxidant alpha-tocopherol ameliorates glycemic control of GK rats, a model of type 2 diabetes

We have shown recently that oxidative stress by chronic hyperglycemia damages the pancreatic beta-cells of GK rats, a model of non-obese type 2 diabetes, which may worsen diabetic condition and suggested the administration of antioxidants as a supportive therapy. To determine if natural antioxidant alpha-tocopherol (vitamin E) has beneficial effects on the glycemic control of type 2 diabetes, GK rats were fed a diet containing 0, 20 or 500 mg/kg diet alpha-tocopherol. Intraperitoneal glucose tolerance test revealed a significant increment of insulin secretion at 30 min and a significant decrement of blood glucose levels at 30 and 120 min after glucose loading in the GK rats fed with high alpha-tocopherol diet. The levels of glycated hemoglobin A1c, an indicator of glycemic control, were also reduced. Vitamin E supplementation clearly ameliorated diabetic control of GK rats, suggesting the importance of not only dietary supplementation of natural antioxidants but also other antioxidative intervention as a supportive therapy of type 2 diabetic patients.     

Peroxynitrite does not impair pulmonary and systemic vascular responses.

The effects of peroxynitrite (ONOO-) on vascular responses were investigated in the systemic and hindquarters vascular bed and in the isolated perfused rat lung. Intravenous injections of ONOO- decreased systemic arterial pressure, and injections of ONOO- into the hindquarters decreased perfusion pressure in a dose-related manner. Injections of ONOO- into the lung perfusion circuit increased pulmonary arterial perfusion pressure. Responses to ONOO- were rapid in onset, short in duration, and repeatable without exhibiting tachyphylaxis. Repeated injections of ONOO- did not alter systemic, hindquarters, or pulmonary responses to endothelium-dependent vasodilators or other vasoactive agonists and did not alter the hypoxic pulmonary vasoconstrictor response. Injections of sodium nitrate or nitrite or decomposed ONOO- had little effect on vascular pressures. Pulmonary and hindquarters responses to ONOO- were not altered by a cyclooxygenase inhibitor in a dose that attenuated responses to arachidonic acid. These results demonstrate that ONOO- has significant pulmonary vasoconstrictor, systemic vasodepressor, and vasodilator activity; that short-term repeated exposure does impair vascular responsiveness; and that responses to ONOO- are not dependent on cyclooxygenase product release.     

The bactericidal and morphological effects of peroxynitrite on Helicobacter pylori

Peroxynitrite (ONOO-) is correlated with the pathogenesis of Helicobacter pylori-induced peptic ulcer diseases. We aimed to investigate the time- and concentration-dependent bactericidal and morphological effects of ONOO- on H. pylori. Authentic ONOO- was synthesized as quenched-flow method. A stock culture of H. pylori NCTC 11637 was exposed to different concentrations of ONOO- (0.1-40 micromol/L) or decomposed ONOO- or fresh medium. Samples were taken at 0, 15, 30, 60, and 120 minutes, for the evaluation of viable bacteria and bacterial morphology with gram strain and transmission electron microscopy. Decomposed ONOO- showed no bactericidal activity against H. pylori. ONOO- application caused a decrease in the number of viable bacteria within the first 15 minutes. The significant conversion of H. pylori from spiral form to coccoid form was determined with 10 micromol/L of ONOO-, and higher concentrations caused lysis of the cells. Separation of cell wall, bleb formation, vacuolization, decrease of secretory granules, and lysis of bacteria were the morphological effects of ONOO- on H. pylori. Because the morphology of the bacteria is one of the important factors in virulence; peroxynitrite-related morphological effects might have an impact in the progress of the H. pylori-induced peptic ulcer diseases.