一氧化氮对心肌梗死后心肌细胞凋亡的影响

目的研究不同浓度一氧化氮(NO)对心肌梗死后心肌组织抗氧化损伤能力(T-AOC)、bcl-2、bax蛋白表达及细胞凋亡的影响。方法新西兰兔32只,随机分为4组,(每组8只)。假手术组(Sham组)、心肌梗死组(MI组)、低剂量消心痛组(LISDN组,1.5mg·kg-1·d-1)、高剂量消心痛组(HISDN组,4.0mg·kg-1.d-1),皆3次/d灌胃。6周后取梗死灶边缘缺血心肌制作组织匀浆进行NO浓度(以NO2-/NO3-间接表示)、T-AOC测定,并作病理观察;免疫组化观察各组bcl-2、bax蛋白表达;TUNEL法比较其细胞凋亡程度。结果HISDN组心肌间质水肿,较多心肌纤维化与炎性细胞浸润,可见局灶性肌丝溶解,肌浆网明显扩张。而LISDN组病理改变较轻。与HISDN组比较,LISDN组心肌组织匀浆中NO浓度降低而T-AOC升高(P<0.05),bcl-2表达阳性率增高而bax表达率降低(P<0.01),细胞凋亡数低于HISDN组(P<0.01)。结论高浓度NO降低心肌梗死后心肌细胞T-AOC并增加细胞凋亡,而低浓度NO显示出更好保护作用。     

Hydrogen peroxide differentially modulates cardiac myocyte nitric oxide synthesis

Nitric oxide (NO) and hydrogen peroxide (H(2)O(2)) are synthesized within cardiac myocytes and play key roles in modulating cardiovascular signaling. Cardiac myocytes contain both the endothelial (eNOS) and neuronal (nNOS) NO synthases, but the differential roles of these NOS isoforms and the interplay of reactive oxygen species and reactive nitrogen species in cardiac signaling pathways are poorly understood. Using a recently developed NO chemical sensor [Cu(2)(FL2E)] to study adult cardiac myocytes from wild-type, eNOS(null), and nNOS(null) mice, we discovered that physiological concentrations of H(2)O(2) activate eNOS but not nNOS. H(2)O(2)-stimulated eNOS activation depends on phosphorylation of both the AMP-activated protein kinase and kinase Akt, and leads to the robust phosphorylation of eNOS. Cardiac myocytes isolated from mice infected with lentivirus expressing the recently developed H(2)O(2) biosensor HyPer2 show marked H(2)O(2) synthesis when stimulated by angiotensin II, but not following β-adrenergic receptor activation. We discovered that the angiotensin-II-promoted increase in cardiac myocyte contractility is dependent on H(2)O(2), whereas β-adrenergic contractile responses occur independently of H(2)O(2) signaling. These studies establish differential roles for H(2)O(2) in control of cardiac contractility and receptor-dependent NOS activation in the heart, and they identify new points for modulation of NO signaling responses by oxidant stress.     

Cholestasis induces apoptosis in mice cardiac cells: the possible role of nitric oxide and oxidative stress

Background/Aims: Acute cholestasis is associated with cardiovascular complications. The purpose of the present study was to investigate the effect of cholestasis on heart apoptosis and the involvement of nitric oxide (NO) and oxidative stress in the possible altered apoptosis of cholestatic hearts. Methods: Cholestasis was induced by bile duct–ligation, and sham‐operated mice served as controls. Three days after the surgery, heart tissues were evaluated for apoptosis and the level of malondialdehyde (MDA), and the activities of catalase (CAT), glutathione peroxidase (GSHPx) and superoxide dismutase (SOD) have been studied in cardiac tissues. The role of treatment with l ‐NAME, a non‐selective inhibitor of NO synthase, or with d ‐NAME, an inactive isomer of l ‐NAME, on cholestatic and sham cardiac apoptosis, level of MDA and CAT, SOD and GSHPx activities was also investigated. The content of NO in cardiac tissue was also determined. Results: Cholestatic hearts showed structural abnormalities and increased apoptosis compared with sham hearts. Treatment with l ‐NAME, but not d ‐NAME, improved both structural abnormalities and enhanced apoptosis of cholestatic hearts. Cholestatic hearts also had an increased level of MDA and decreased activities of CAT and GSHPx, which were not modified by d ‐NAME treatment. By l ‐NAME treatment, the level of MDA decreased and activities of CAT, GSHPx and SOD increased in BDL mice. The content of NO was higher in cholestatic cardiac tissue, which was decreased by l ‐NAME treatment. Conclusion: In conclusion, apoptosis in cholestatic heart might have occurred because of NO overproduction, which could induce oxidative stress in the heart of cholestatic mice.     

一氧化氮和内皮素在高血压左室肥厚形成中的作用

目的 探讨一氧化氮（NO）和内皮素（ET）在高血压左室肥厚（LVH）形成中的作用。方法 采用放射免疫分析法（RIA）和硝酸还原酶法检测30例单纯原发性高血压（EH,观察Ⅰ组）、30名健康体检者（对照组）及20例EH伴LVH（观察Ⅱ组）患者降压治疗前后血清ET、NO水平。并对结果进行相关分析。结果 观察Ⅰ组血清ET明显高于对照组、NO明显低于对照组（P均〈0．01）;观察Ⅱ组血清ET明显高于观察Ⅰ组、NO明显低于观察Ⅰ组（P均〈0．01）,且ET与NO水平呈负相关（r=0．586,P〈0．01）;左心室重量指数（LVMI）与ET呈正相关（r=0．427,P〈0．05）、与NO呈负相关（r=0．653,P〈0．01）。观察Ⅱ组治疗后,血清ET水平明显低于治疗前、NO水平明显高于治疗前（p均〈0．01）。结论 ET和NO两者失衡可能参与了EH及LVH形成的病理生理过程。     

Effects of nitric oxide donor S-nitrosoglutathione on apoptosis of apheresis platelets

Objectives: The aim of this study is to investigate the effects of a Nitric oxide (NO) donor, S-nitrosoglutathione (GSNO), on apoptosis and the improvement of preservation quality in apheresis platelets.

Methods: A GSNO solution - to make the final GSNO concentration of 100?uM was added into fresh apheresis platelets, and the parameters associated with platelet morphology, metabolism, and apoptosis were dynamically monitored for seven days.

Results: The results showed that the NO level was remarkably higher during the whole storage stageafter GSNO injection. The number of depolarized platelets and platelets with phosphatidylserine valgus were significantly reduced in the GSNO group compared to that of the control group at some time point. The expression of Bcl-xL mRNA on day 5 of storage in the experimental group was significantly higher than that of the control group, but the expression of Bcl-xL protein was not significantly higher than that in the control group. In addition, Bak and Bax mRNA expression levels in the experimental group were significantly lower than those in the control group, but Bak and Bax protein expression levels were not statistically different. Meanwhile, caspase-3 activity was significantly inhibited.

Discussion and conclusion: These data suggest that the addition of a certain dose of GSNO as a NO donor during platelet storage could inhibit platelet apoptosis and reduce platelet storage lesion (PSL) to a certain extent.     

Exogenous nitric oxide inhibits apoptosis in guinea pig gastric mucous cells

BACKGROUND: Increased nitric oxide (NO) synthase activity and enhanced apoptosis are features of gastric mucosa infected with Helicobacter pylori and a causative relation has been suggested. However, although NO can promote apoptosis, its actions vary with cell type. AIMS: To determine whether exogenous NO, derived from an NO donor, might promote or counteract apoptosis in gastric mucous epithelial cells. METHODS: Primary cultures of guinea pig gastric mucosal cells were exposed to the NO donor S-nitroso-N-acetyl-penicillamine (SNAP) for 24 hours. Apoptosis was detected from nuclear staining with Hoechst 33258, in situ nick end labelling of DNA, and the presence of DNA "ladders" in cell extracts. Cyclic GMP content and caspase activity were determined by immunoassay and fluorimetric assay respectively. RESULTS: SNAP 1 mM did not alter the small proportion of cells on the culture plate (3-6%) which exhibited features of apoptosis. However, SNAP produced an inhibition of apoptosis, and of caspase 3 like activity, when enhanced by 25 microM N-hexanoyl-D-sphingosine (C(6)-ceramide), or by detachment of cells from the culture plate. The guanylate cyclase inhibitor, 1H-1, 2, 4-oxadiazole-4, 3-a-quinoxaline-1-one (ODQ), prevented the stimulation of cyclic GMP by SNAP, but not the anti- apoptotic effects of the NO donor. The cyclic GMP analogues 8-bromo-cyclic GMP and 8-(4-chlorophenylthio) guanosine-3',5'- cyclic monophosphate did not significantly inhibit apoptosis in the mucosal cells. CONCLUSIONS: Exogenous NO inhibited apoptosis in guinea pig gastric mucous cells by a mechanism which did not involve elevation of cyclic GMP. NO, if produced from NO synthase during infection with H pylori, may therefore counter the proapoptotic effects of this pathogen.     

一氧化氮在心肌细胞凋亡中的作用

作者综述了一氧化氮 （NO）对心肌细胞凋亡的作用机制。NO对心肌细胞的作用有双重性 :既是组织损伤的中间介质 ,又在心肌缺血 /再灌注损伤中有保护心肌作用。它可通过氧化应激反应 ,作用于心肌细胞的一些蛋白质、酶类、细胞因子以及胞液的钙超载等途径来影响心肌细胞凋亡     

一氧化氮在阿霉素肾病大鼠发病中的作用和机制

目的探讨一氧化氮(NO)在阿霉素(ADR)肾病病鼠发病中的作用及其机制.方法复制阿霉素肾病模型,分别用L-精氨酸(L-Arg)及N-硝酸-L精氨酸甲基酯(L-NAME)进行干预,用硝酸还原酶法测定肾皮质匀浆NO代谢产物NO2-/NO-3水平来反映NO水平,用末端标记法和免疫组化法分别检测皮质部细胞凋亡和Bcl-2、Bax、c-Myc蛋白表达情况,用原位杂交法测定皮质部细胞p53-mRNA转录水平.结果①ADR组肾皮质匀浆NO2-/NO3-水平明显低于对照组(P＜0.01),皮质部细胞凋亡数、p53-mRNA水平和c-Myc蛋白表达均分别明显高于对照组(P均小于0.01),肾小管细胞Bcl-2蛋白表达明显低于对照组而Bax蛋白表达却明显高于对照组(P均小于0.01).②ADR+L-Arg组肾皮质匀浆NO2-/NO3-水平明显高于ADR组(P＜0.01),皮质部细胞凋亡数、p53-mRNA水平和c-Myc蛋白表达则分别明显低于ADR组(P均小于0.05),肾小管细胞Bcl-2蛋白表达明显高于ADR组而Bax蛋白表达则明显低于ADR组(P均小于0.05).③ADR+L-NAME组肾皮质匀浆NO2/NO-3水平明显低于ADR组(P＜0.01),皮质部细胞凋亡数、p53-mRNA水平和c-Myc蛋白表达均明显高于ADR组(P均小于0.05),肾小管细胞Bcl-2蛋白表达明显低于ADR组而肾小管细胞Bax蛋白表达明显高于ADR组(P均小于0.05).结论ADR能显著降低ADR肾病病鼠肾皮质NO水平,诱导肾皮质细胞凋亡.L-Arg可对抗ADR的上述作用,在一定程度上维持NO水平,减少细胞凋亡;L-NAME增强ADR作用,进一步降低NO水平,增加细胞凋亡.本实验结果提示,NO水平的增减与细胞凋亡相关,NO可能参与细胞凋亡.     

Elevated nitric oxide levels associated with hepatic cell apoptosis during liver injury

Hepatic injury is a major event in liver surgery such as liver transplantation and it always leads to hepatic cell apoptosis. Nitric oxide (NO) is a key signaling regulation molecule. Many researchers have shown that increased NO level can influence liver cell apoptosis by promoting or inhibiting the relative signaling pathways that are involved in the caspase family, Bax/Bcl‐2, mitochondria, oxidative stress, death receptors, and mitogen‐activated protein kinases. Elucidating the relationships between NO and hepatic cell apoptosis is necessary for ameliorating prognosis of liver surgery. This article reviews the newest research progress in the relationships between higher NO levels and hepatic cell apoptosis in liver injury.     

Toxoplasma gondii infection induces apoptosis in noninfected macrophages: role of nitric oxide and other soluble factors

Apoptosis has been found to help in the defence against pathogens. Infection with the obligate intracellular parasite Toxoplasma gondii is known to trigger host-cell apoptosis. When using a T. gondii-infected macrophage cell line, J774A.1, treatment with IFN-gamma significantly enhanced apoptosis in noninfected bystander cells while parasitized cells became relatively resistant. Infection and IFN-gamma treatment activated the expression of inducible nitric oxide synthase (iNOS), and the production of nitric oxide (NO) and treatment of cells with an iNOS inhibitor, N(G)-monomethlyl-L-arginine acetate (L-NMMA) reduced the apoptosis frequency. However, the reversal was only partial suggesting that not only NO, but also other, as of yet, unknown factors are induced. Finally, we studied the effect in vivo by infecting mice with either a virulent or an avirulent strain. Challenge with the virulent strain lead to a higher parasite burden, induced host-cell apoptosis in peritoneal cells, and produced higher levels of IFN-gamma and NO. Moreover, treatment of mice with a NO synthase inhibitor, aminoguanidine, partially inhibited the host-cell apoptosis induced by the parasite infection. Altogether, our findings indicate that apoptosis in bystander host cells is due to the secretion of NO and other soluble factors released by parasite-infected cells.     

辛伐他汀对一氧化氮缺乏性大鼠心肌肥大的抑制作用及机制探讨

目的:观察辛伐他汀对一氧化氮(NO)缺乏性高血压大鼠心肌肥大的作用并探讨其机制。方法:40只大鼠随机分为对照组、模型组、小剂量和大剂量辛伐他汀组。用一氧化氮合酶抑制剂制备心肌肥大模型。6周后测定大鼠心肌肥大指标和心肌血红素氧合酶(HO)活性。结果:模型组动物心肌明显肥大,辛伐他汀治疗组动物较模型组心肌肥大明显减轻,左心室重量指数(LVMI)、心肌BNP含量和羟脯氨酸含量均显著降低(均P<0.01),心肌HO活性明显升高(P<0.01),心肌HO活性与LVMI、心肌羟脯氨酸含量和心肌BNP含量呈明显负相关。结论:辛伐他汀可抑制NO缺乏性大鼠心肌肥大并诱导心肌HO活性升高,HO1CO通路可能是他汀类药物非降脂作用的重要机制之一。     

一氧化氮与原发性高血压及左室肥厚的关系

目的 探讨一氧化氮（NO）在原发性高血压（EH）患者中的变化，以及与左室肥厚（LVH）的关系。方法 分别选取EH有LVH患者、EH无LVH患者及正常人各30例，检测NO水平及左室重量（LVM），进行组间比较及相关分析。结果 1．EH有LVH组NO水平明显低TEH无LVH组、正常对照组，EH无LVH组NO水平明显低于正常对照组；而室间隔舒张末期厚度（IVS）、左室后壁舒张末期厚度（LVPw）、LVM水平相反俨〈0．01）。2．血压与NO呈负相关、与LVM呈正相关，NO与LVM呈负相关（r〉0或，〈0，P〈0．01或〈0．05）。结论 NO参与了EH及LVH形成的病理生理过程。     

阿托伐他汀在心肌细胞肥大治疗中的作用

大量研究表明阿托伐他汀可干预心室重塑的形成和发展.应用阿托伐他汀能从不同途径发挥独特的心血管保护效应.本文从心肌细胞肥大这个角度阐述阿托伐他汀对心室重塑的影响.     

解耦联蛋白-2与压力超负荷大鼠心肌肥厚中的细胞凋亡

目的探讨心肌解耦联蛋白-2（ucP2）与压力超负荷心肌肥厚中心肌细胞凋亡的关系。方法采用腹主动脉缩窄法建立大鼠压力超负荷模型,假手术大鼠作为对照组。术后1,2,4,7,14,21,30d,RT-PCR法测定UCP2mRNA含量,TUNEL法检测心肌细胞凋亡水平。结果（1）与对照组比较,压力超负荷组在术后4d UCP2 mRNA含量上调,并持续增高至30d。（2）压力超负荷组心肌细胞凋亡在术后1d即升高,在4d时进入高峰期并持续至7d,其后低水平持续存在,直至实验结束。而对照组未发现凋亡细胞。结论UCP2可能参与了压力超负荷心肌肥厚中细胞凋亡的调控,但其确切机制有待进一步研究。