Nitric oxide from inducible nitric oxide synthase sensitizes the inflamed aorta to hypoxic damage via respiratory inhibition

We tested whether nitric oxide (NO) could synergize with hypoxia to induce damage to the aorta isolated from rat. We found that 4 h of mild hypoxia (5% O2) caused substantial necrosis of isolated rat aortae (measured as lactate dehydrogenase release) if inducible NO synthase (iNOS) had previously been induced by endotoxin plus interferon-gamma. Mild hypoxia caused no significant necrosis in the absence of this inflammatory activation, and inflammatory activation caused little damage at a higher oxygen levels (21% oxygen). An iNOS inhibitor (1400W) prevented the necrosis induced by inflammation plus mild hypoxia, whereas the NO donor diethylenetriamine (DETA)/NO adduct, 0.5 mM) greatly sensitized the noninflammed aorta to necrosis induced by mild hypoxia. NO inhibited aortic respiration to a greater degree at lower oxygen concentrations, consistent with NO inhibition of cytochrome oxidase in competition with oxygen. A specific inhibitor of mitochondrial respiration, myxothiazol, caused necrosis of aortae over a similar time course to NO. DETA/NO plus mild hypoxia-induced cell death was substantially reduced by a glycolytic intermediate 3-phosphoglycerate, suggesting that necrosis resulted from energy depletion secondary to respiratory inhibition. This NO-induced sensitization of aorta to mild hypoxia may be important in sepsis and other pathologies where iNOS is expressed.     

In vitro modulation of inducible nitric oxide synthase gene expression and nitric oxide synthesis by procalcitonin

OBJECTIVE: Serum procalcitonin (PCT) concentration was recently introduced as valuable diagnostic marker for systemic bacterial infection and sepsis. At present, the cellular sources and biological properties of PCT are unclear. During sepsis and septic shock, inducible nitric oxide synthase (iNOS) gene expression is stimulated followed by the release of large amounts of nitric oxide (NO). We investigated the possible association between PCT and iNOS gene expression in an in vitro cell culture model. DESIGN: Prospective, controlled in vitro cell culture study. SETTING: University research laboratories. INTERVENTIONS: Confluent rat vascular smooth muscle cells (VSMC) were incubated for 24 hrs and 48 hrs with PCT (1 ng/mL, 10 ng/mL, 100 ng/mL, 1,000 ng/mL, 5,000 ng/mL) alone or with the combination of tumor necrosis factor-alpha (TNF-alpha, 500 U/mL) plus interferon-gamma (IFN-gamma, 100 U/mL). iNOS gene expression was measured by qualitative as well as quantitative polymerase chain reaction analysis, NO release was estimated by the modified Griess method. MEASUREMENTS AND MAIN RESULTS: PCT in increasing concentrations had no effect on iNOS gene expression and nitrite/nitrate release for 24 hrs and 48 hrs, respectively. However, PCT ameliorated TNF-alpha/IFN-gamma-induced iNOS gene expression in a dose-dependent manner (maximal inhibition at PCT 100 ng/mL by -66% for 24 hrs and -80% for 48 hrs). This was accompanied by a significantly reduced release of nitrite/nitrate into the cell culture supernatant (maximal reduction at PCT 100 ng/mL by -56% and -45% for 24 hrs and 48 hrs, respectively). CONCLUSIONS: We conclude that recombinant PCT inhibits the iNOS-inducing effects of the proinflammatory cytokines TNF-alpha/ IFN-gamma in a dose-dependent manner. This might be a counter-regulatory mechanism directed against the large production of NO and the concomitant systemic hypotension in severe sepsis and septic shock.     

Preclinical evaluation of inducible nitric oxide synthase lipoplex gene therapy for inhibition of stent-induced vascular neointimal lesion formation

Several reports have established the concept of nitric oxide synthase (NOS) gene transfer for inhibiting smooth muscle cell (SMC) proliferation after vascular injury. To minimize potential risks associated with viral gene transfer, we developed a liposome-based gene transfer approach employing inducible NOS (iNOS) overexpression for inhibition of stent-induced neointimal lesion formation. Therapeutic lipoplexes were transferred to femoral or coronary arteries of Goettingen minipigs, using the Infiltrator local drug delivery device. Efficiency of local iNOS lipoplex transfer was analyzed by iNOS-specific immunohistochemistry. NO-mediated inhibition of stent-induced neointimal lesion formation was analyzed by intravascular ultrasound (IVUS) and computerized morphometry. Gene transfer efficiency increased dose dependently to a maximum of 44.3 +/- 4.2% iNOS-positive vessel area (dose, 2 microg of iNOS lipoplex). Proliferating cell nuclear antigen (PCNA) expression of medial SMCs (immunohistochemistry) was inhibited significantly by transfer of 2 microg of iNOS lipoplexes (111 +/- 27 cells [iNOS] versus 481 +/- 67 cells [control; PCNA-positive medial cells]). IVUS analysis demonstrated that local transfer of iNOS lipoplexes resulted in a significant reduction of femoral in-stent plaque area (control, 40.85 +/- 6.37 mm(2); iNOS, 24.69 +/- 1.8 mm(2); p = 0.03). Coronary in-stent lesion formation was reduced by about 45% as determined by histologic morphometry (control, 4.0 +/- 0.29; iNOS, 2.2 +/- 0.30; p < 0.01). In conclusion, this study demonstrates that local intramural delivery of iNOS lipoplexes can exert therapeutic effects in inhibiting stent-induced neointimal lesion formation. Together with the nonviral character of this gene therapy approach, these findings may have important impact on the transition of NOS-based gene therapy to clinical practice.     

生长反应因子1特异的脱氧核酶与大鼠颈动脉损伤后诱生型一氧化氮合酶表达的关系

目的:观察生长反应因子1特异的脱氧核酶ED5对大鼠颈动脉血管损伤后诱生型一氧化氮合酶表达的影响,探讨生长反应因子1特异的脱氧核酶对血管损伤后内膜增生的抑制作用。方法:实验于2004-03/2004-07在中国医科大学实验动物部完成。选用健康雄性Wistar大白鼠96只。随机将动物分为4组:治疗组、稀释液对照组、转染液对照组和假手术组,每组24只,每组分为4个时间点(3,7,14,21d)进行观察。①血管球囊损伤的动物模型制作:麻醉后,切开鼠颈正中,钝性分离左颈动脉,血管夹暂时阻断左颈总动脉近心、远心端血流,用2F导管从颈外动脉插入左颈总动脉内,推入0.2mL生理盐水充盈气囊,反复抽拉球囊3次,造成左颈总动脉内膜损伤。②分组干预:假手术组只进行颈动脉结扎,但不插入导管,即不造成动脉内膜损伤。稀释液对照组、转染液对照组、治疗组均在造成血管球囊损伤模型的同时,局部注射200μL的1mmol/LMgCl2液;局部注射含30μL的FuGENE6Reagent的MgCl2液200μL;颈外动脉给予含有异硫氰酸荧光素标记的生长反应因子1特异的脱氧核酶500μg+转染试剂FuGENE630μL的MgCl2液200μL。③诱生型一氧化氮合酶mRNA水平检测:采用半定量反转录聚合酶链反应。④诱生型一氧化氮合酶蛋白合成检测:采用免疫印迹法。⑤血管内膜增生情况观察:苏木精-伊红染色,光镜显微镜下观察,应用计算机图像分析软件测定血管内膜和中膜厚度。⑥血管内膜和中膜一氧化氮合酶蛋白表达检测:采用免疫组织化学法。⑦统计学分析:多组间比较采用单因素方差分析,两组间比较采用LSD-t检验。结果:大鼠96只均进入结果分析。①大鼠血管内皮损伤后血管病理形态学改变:内皮损伤后3d内膜增生不明显,7d内膜开始增生,14和21d时内膜增生明显。②血管组织诱生型一氧化氮合酶mRNA的表达及蛋白合成结果:假手术组大鼠颈动脉无诱生型一氧化氮合酶mRNA的表达,球囊损伤后3,7,14,21d均出现诱生型一氧化氮合酶蛋白表达量的上调。与对照组比较,治疗组在各个时间点的诱生型一氧化氮合酶mRNA水平和蛋白表达量增高更显著(P<0.05)。③术后7,14,21d血管内中膜厚度:2个对照组和治疗组明显大于假手术组(P<0.01);治疗组明显小于2个对照组(P<0.01)。④血管组织诱生型一氧化氮合酶蛋白质表达:2个对照组和治疗组明显大于假手术组(P<0.01);治疗组明显大于2个对照组(P<0.01)。结论:①大鼠颈动脉球囊损伤后诱生型一氧化氮合酶表达略增加,这可能是血管组织的一种代偿反应,同时内膜增生明显。②经生长反应因子1特异的脱氧核酶治疗出现诱生型一氧化氮合酶高表达进一步增加,内膜增生明显减轻,生长反应因子1特异的脱氧核酶通过增加诱生型一氧化氮合酶的表达而达到抑制血管球囊损伤后内膜增生的作用。     

生长反应因子1特异的脱氧核酶与大鼠颈动脉损伤后诱生型一氧化氮合酶表达的关系

目的：观察生长反应因子1特异的脱氧核酶ED5对大鼠颈动脉血管损伤后诱生型一氧化氮合酶表达的影响，探讨生长反应因子1特异的脱氧核酶对血管损伤后内膜增生的抑制作用。方法：实验于2004-03／2004-07在中国医科大学实验动物部完成。选用健康雄性Wistar大白鼠96只。随机将动物分为4组：治疗组、稀释液对照组、转染液对照组和假手术组，每组24只，每组分为4个时间点（3，7，14，21d）进行观察。①血管球囊损伤的动物模型制作：麻醉后，切开鼠颈正中，钝性分离左颈动脉，血管夹暂时阻断左颈总动脉近心、远心端血流，用2F导管从颈外动脉插入左颈总动脉内，推入0．2mL生理盐水充盈气囊，反复抽拉球囊3次，造成左颈总动脉内膜损伤。②分组干预：假手术组只进行颈动脉结扎，但不插入导管，即不造成动脉内膜损伤。稀释液对照组、转染液对照组、治疗组均在造成血管球囊损伤模型的同时，局部注射200μL的lmmol／L MgCl2液；局部注射含30μL的FuGENE6Reagent的MgCl2液200μL；颈外动脉给予含有异硫氰酸荧光素标记的生长反应因子1特异的脱氧核酶500μg＋转染试剂FuGENE630μL的MgCl2液200μL。③诱生型一氧化氮合酶mRNA水平检测：采用半定量反转录聚合酶链反应。，④诱生型一氧化氮合酶蛋白合成检测：采用免疫印迹法。⑤血管内膜增生情况观察：苏木精一伊红染色，光镜显微镜下观察，应用计算机图像分析软件测定血管内膜和中膜厚度。⑥血管内膜和中膜一氧化氮合酶蛋白表达检测：采用免疫组织化学法。⑦统计学分析：多组问比较采用单因素方差分析，两组间比较采用LSD-t检验。结果：大鼠96只均进入结果分析。①大鼠血管内皮损伤后血管病理形态学改变：内皮损伤后3d内膜增生不明显，7d内膜开始增生，14和21d时内膜增生明显。②血管组织诱生型一氧化氮合酶mRNA的表达及蛋白合成结果：假手术组大鼠颈动脉无诱生型一氧化氮合酶mRNA的表达，球囊损伤后3，7，14，21d均出现诱生型一氧化氮合酶蛋白表达量的上调。与对照组比较，治疗组在各个时间点的诱生型一氧化氮合酶mRNA水平和蛋白表达量增高更显著（P〈0．05）。③术后7，14，21d血管内中膜厚度：2个对照组和治疗组明显大于假手术组（P〈0．01）；治疗组明显小于2个对照组（P〈0．01）。④血管组织诱生型一氧化氮合酶蛋白质表达：2个对照组和治疗组明显大于假手术组（P〈0．01）；治疗组明显大于2个对照组（P〈0．01）。结论：①大鼠颈动脉球囊损伤后诱生型一氧化氮合酶表达略增加，这可能是血管组织的一种代偿反应，同时内膜增生明显。②经生长反应因子1特异的脱氧核酶治疗出现诱生型一氧化氮合酶高表达进一步增加，内膜增生明显减轻，生长反应因子1特异的脱氧核酶通过增加诱生型一氧化氮合酶的表达而达到抑制血管球囊损伤后内膜增生的作用。     

缺氧诱导因子1α和诱导型一氧化氮合酶基因在缺氧性肺动脉高压大鼠发病过程中的表达

背景:关于缺氧性肺动脉高压发病过程中缺氧诱导因子1α和诱导型一氧化氮合酶在肺动脉壁内的动态变化尚需探讨。目的:观察不同缺氧时间点肺动脉壁内缺氧诱导因子1α和诱导型一氧化氮合酶基因表达,探讨其在缺氧性肺动脉高压发病机制中的作用。设计:对比观察的动物实验。单位:南华大学附属第二医院呼吸内科。材料:选用健康雄性Wistar大鼠40只,清洁级,6～8周龄,体质量(220±10)g。按随机表法分为对照组(n=8)和缺氧组(n=32),其中缺氧组又分为缺氧后3,7,14,21d4个时间点进行观察,每个时间点8只。方法:实验于2004-08/2005-12在南华大学肿瘤研究所完成。缺氧组大鼠按李启芳报道的方法进行干预。对照组大鼠置于同一室内,除不缺氧外,余同缺氧组。按照观察时间点将大鼠麻醉后,右颈外静脉插入微导管,连接多导生理记录仪,检测大鼠肺动脉平均压。将大鼠处死取出心脏称量右心室、左室加室间隔的质量,以右室肥大指数反映右心室肥厚程度。取大鼠右上肺组织,进行苏木精-伊红染色和弹性纤维染色。用病理图像分析软件测定肺动脉管壁面积/管总面积、管腔面积/管总面积、肺细小动脉中膜平滑肌细胞密度、肺细小动脉中膜厚度作为肺小血管重塑指标。对肺小血管壁缺氧诱导因子1α,诱导型一氧化氮合酶进行原位杂交和免疫组织化学检测,以肺细小动脉管壁平均吸光度值作为mRNA表达和蛋白水平的相对含量。主要观察指标:①大鼠肺动脉平均压、右心室肥厚程度和肺小血管重塑指标的变化。②缺氧诱导因子1和诱导型一氧化氮合酶的表达及其与肺动脉平均压,肺血管重塑的关系。结果:共纳入Wistar大鼠40只全部进入结果分析。①缺氧7d时肺动脉平均压明显高于对照组(P<0.05),14d达到最高水平,之后维持于此水平。②缺氧14d右心室肥大指数高于对照组(P<0.05)。③缺氧7d肺小动脉管壁增厚,管腔变窄,肺动脉管壁面积/管总面积、管腔面积/管总面积与对照组比较,差异明显(P<0.05);缺氧14d可见肺小动脉中膜和肺细小动脉中膜平滑肌细胞密度增高,肺细小动脉中膜厚度明显增加(P<0.05)。21d管腔进一步变窄,平滑肌增生明显。④缺氧诱导因子1和诱导型一氧化氮合酶mRNA的表达:对照组大鼠呈弱阳性表达;缺氧3d和7d缺氧诱导因子1αmRNA相对量无明显变化,14d时明显增高,此后维持于高水平。诱导型一氧化氮合酶mRNA在缺氧3d明显高于对照组,7d达到高峰,14d接近对照组水平,21d再次升高,但低于缺氧3d时。⑤缺氧诱导因子1α主要表达于血管内膜和中膜,而诱导型一氧化氮合酶表达涉及血管全层。诱导型一氧化氮合酶在对照组肺血管内膜和中膜均弱阳性表达,缺氧3d与对照组差异不明显,7d中膜、内膜表达明显,14d血管中膜增厚,表达增强。在血管外膜,对照组诱导型一氧化氮合酶为阴性,各缺氧组均阳性表达。⑥mPAP与肺血管重塑正相关(r=0.976,P<0.01),缺氧诱导因子1αmRNA与诱导型一氧化氮合酶蛋白正相关(r=0.927,P<0.05)。结论:缺氧诱导因子1α和诱导型一氧化氮合酶均在大鼠缺氧性肺动脉高压的发病过程中发挥作用,且缺氧诱导因子1α与诱导型一氧化氮合酶基因表达可能存在相互调控。     

活血化瘀汤对骨折愈合过程中诱导型一氧化氮合酶基因表达的影响

目的:观察活血化瘀汤对骨折愈合中诱导型一氧化氮合酶mRNA表达的影响,从而调控成骨作用。方法:实验于2002-12/2004-08在华中科技大学基础学院分子生物学实验室完成。将24只SD大鼠胫骨中段闭合骨折骨髓内克氏针固定制成骨折模型,随机分为活血化瘀汤组(n=12)及生理盐水组(n=12);于骨折后4,7,14,21d收集骨痂样本,反转录聚合酶链反应测定诱导型一氧化氮合酶的mRNA表达水平。结果:24只大鼠均进入结果分析。骨折后7,14,21d所有骨痂样本诱导型一氧化氮合酶的mRNA表达增强,骨折后14d达到峰值,活血化瘀汤组与生理盐水组比较,骨折后7,14d骨痂诱导型一氧化氮合酶基因表达显著性增强(P=0.0037)。结论:活血化瘀汤可能通过增加早期大鼠骨痂诱导型一氧化氮合酶源性一氧化氮,影响骨细胞增殖功能,从而促进骨折愈合。     

诱导型一氧化氮合酶基因启动子区微卫星多态与急性冠状动脉综合征

目的:研究中国汉族人群诱导型一氧化氮合酶(NOS2A)基因启动子区-2.5kb微卫星CCTTT串联重复序列多态与急性冠状动脉综合征(ACS)的相关性。方法:应用微卫星分析技术,检测CCTTT微卫星多态在117例ACS患者和125名健康对照者中的频率分布。结果:根据CCTTT微卫星多态对NOS2A基因转录水平的影响,将CCTTT串联重复序列分为S(重复次数≤13)和L(重复次数>13)2类,基因型分布在ACS组(S/S=48,S/L=64,L/L=5)和对照组(S/S=56,S/L=49,L/L=20)间存在显著差异(χ2=11.354,P=0.003)。对照组的L/L基因型频率显著高于ACS组,r为0.234(95%CI=0.085～0.647,P=0.003),可能具有保护性作用。分层研究发现,女性ACS与对照组相比,基因型分布存在显著差异(χ2=8.134,P=0.017)。结论:NOS2A基因启动子区CCTTT微卫星多态可能与中国汉族ACS,尤其与女性患者的遗传易感性有关。     

Lung, spleen, and kidney are the major places for inducible nitric oxide synthase expression in endotoxic shock: role of p38 mitogen-activated protein kinase in signal transduction of inducible nitric oxide synthase expression

Bacterial lipopolysaccharide (LPS) is known to induce endotoxic shock with inducible nitric oxide (NO) synthase (iNOS) expression and NO production. However, the major place for NO production in shock remains unclear. Although there is some literature about p38 mitogen-activated protein kinase (MAPK) in regulating LPS-induced iNOS expression, the results are contradictory. To interpret the precise cell mechanism and the role of p38 MAPK in the expression of iNOS during endotoxic shock, we carried out the following investigations. A severe endotoxic shock model was reproduced in mice 6 h after LPS injection. The plasma NO level was increased in a dose- and time-dependent manner after LPS stimulation and was suppressed by administration of SB203580 [4-(4-fluorophenyl)-2-4-methylsulfonylphenyl-5-(4-pyridyl) imidazole], a highly specific inhibitor of p38 MAPK. The iNOS expression was increased in many organs, including heart, liver, spleen, lung, gut, and kidney in endotoxic shock. Among them, the highest expression of iNOS mRNA and protein was in the lung, moderate expression was in the spleen and kidney, and the lowest expression was in the heart, gut, and liver. The level of expression in lung was 5.5 times that of iNOS mRNA and was 3.1 times that of iNOS protein than in heart, and 1.6 and 1.8 times that of iNOS mRNA and 1.7 and 1.4 times that of iNOS protein than in spleen and kidney, respectively. The p38 MAPK activity increased after LPS injection, and SB203580 markedly reduced LPS-induced expressions of iNOS protein and mRNA in the lung. The results indicates that lung, spleen, and kidney are the major places for iNOS expression in endotoxic shock and are important therapeutic target organs for attenuating NO production in shock treatment.     

Tissue expression of inducible nitric oxide synthase is closely associated with resistance to Leishmania major

Previous studies with inhibitors of inducible nitric oxide synthase (iNOS) suggested that high-output production of nitric oxide (NO) is an important antimicrobial effector pathway in vitro and in vivo. Here, we investigated the tissue expression of iNOS in mice after infection with Leishmania major. Immunohistochemical staining with an iNOS-specific antiserum revealed that in the cutaneous lesion and draining lymph nodes (LN) of clinically resistant mice (C57BL/6), iNOS protein is found earlier during infection and in significantly higher amounts than in the nonhealing BALB/c strain. Similar differences were seen on the mRNA level as quantitated by competitive polymerase chain reaction. Anti-CD4 treatment of BALB/c mice not only induced resistance to disease, but also restored the expression of iNOS in the tissue. In situ, few or no parasites were found in those regions of the skin lesion and the draining LN which were highly positive for iNOS. By double labeling experiments, macrophages were identified as iNOS expressing cells in vivo. In the lesions of BALB/c mice, cells staining positively for transforming growth factor beta (TGF-beta), a potent inhibitor of iNOS in vitro, were strikingly more prominent than in C57BL/6, whereas no such difference was found for interleukin 4 or interferon gamma (IFN-gamma). In vitro, production of NO was approximately threefold higher in C57BL/6 than in BALB/c macrophages after stimulation with IFN-gamma. We conclude that the pronounced expression of iNOS in resistant mice is an important mechanism for the elimination of Leishmania in vivo. The relative lack of iNOS in susceptible mice might be a consequence of macrophage deactivation by TGF-beta and reduced responsiveness to IFN-gamma.     

Evaluation of a synthetic CArG promoter for nitric oxide synthase gene therapy of cancer

Nitric oxide synthase gene therapy has been shown to be effective at inducing apoptosis in experimental tumours and sensitizing them to radiotherapy. We have also shown that expression of inducible nitric oxide synthase (iNOS) can be effectively restricted to the tumour volume by the use of the radiation inducible promoter (WAF1) to drive the transgene in clinically relevant protocols. A synthetic construct (pE9), incorporating nine radiosensitive CArG elements from the Egr1 promoter, has recently been developed for cancer gene therapy. We have now investigated basal gene expression of transgenes driven by this promoter to assess its suitability for use in iNOS gene therapy protocols in vivo. Transfection of human microvascular endothelial cells (HMEC-1) with pE9iNOS, using a cationic lipid vector, resulted in progressively increasing (<5-fold) levels of iNOS protein expression up to 8 h after transfection. Transfection of an ex vivo rat artery preparation with pE9iNOS caused 83% inhibition of response to the vasoconstrictor phenylephrine (PE). CMViNOS transfection also reduced response to PE, but by only 52%. A single injection of 25 microg of pE9iNOS DNA in a lipid vector into the centre of a murine sarcoma (RIF1) induced iNOS protein expression by four-fold and increased nitrite concentration eight-fold. This caused a 7-day delay in tumour growth and was more effective than the constitutive CMV-driven construct. Our data suggest that generation of NO*, as a result of iNOS overexpression, is capable of further activating the E9 promoter, through a positive feedback loop, yielding stronger and sustained levels of NO*. This pE9iNOS combination may, therefore, be particularly useful in an anticancer gene therapy strategy as its antitumour effect in vivo was clearly superior to that of the strong constitutive promoter, CMV.     

AML1-ETO对p21 WAF1/CIP1启动子转录活性作用的研究

目的观察AML1-ETO融合基因对p21WAF1／CIP1基因启动子转录活性的影响，探讨AML1-ETO促进白血病发生的机制。方法构建p21WAF1／CIP1基因启动子的报告质粒，与AML1-ETO、AML1b和AML1a的表达质粒共转染非洲绿猴肾细胞系CV—1细胞，测定荧光素酶的活性，分析AML1-ETO、AML1b和AML1a对p21WAF1／CIP1基因启动子转录活性的影响。结果在CV—1细胞中，AML1-ETO对p21WAF1／CIP1基因启动子的转录具有明显的抑制作用，在pCMV5-AML1-ETO的剂量为1000ng时，p21WAF1／CIP1启动子的转录活性下降为对照组的（19±4）％，这种作用具有序列特异性和剂量依赖性；AML1b和AML1a对p21WAF1／CIP1基因启动子转录活性的抑制作用不明显，在剂量为1000ng时，p21WAF1／CIP1启动子的转录活性分别下降为对照组的（61±16）％和（594-16）％。结论AML1在与ETO形成融合基因后，其产物由于ETO蛋白能够更有效地募集转录共抑制复合物，其转录抑制活性要比AML1a和AML1b更强；外源的AML1-ETO对p21WAF1／CIP1的作用可能也与细胞系有关。     

Deletion of the inducible nitric oxide synthase gene reduces peripheral morphine tolerance in a mouse model of chronic inflammation

The implication of inducible nitric‐oxide synthase (iNOS) on peripheral tolerance to morphine was evaluated in wild‐type (WT) and iNOS knockout mice. Chronic inflammation was induced by subplantar (s.p.) injection of Complete Freund’s Adjuvant (CFA), and morphine tolerance by subcutaneous implantation of a 75 mg morphine‐pellet. Withdrawal was assessed after the intraperitoneal injection of 2 mg/kg naloxone. Antinociception was assessed (Randall‐Selitto test) 5 min after a fixed dose of s.p. morphine (16 μg). In the absence of inflammation, s.p. morphine did not induce antinociception, while during CFA‐inflammation produced 47.4 ± 0.8 and 38.8 ± 2.7% inhibitions respectively, in each genotype (P < 0.05). In morphine‐tolerant mice with CFA‐inflammation, no antinociception could be elicited in WT mice (2.4 ± 0.3% inhibition); however, iNOS knockout mice showed significant antinociception (33.1 ± 0.9%) (P < 0.001). Thus, iNOS gene deletion partially prevented tolerance to the peripheral effects of morphine, and significantly attenuated withdrawal‐induced hyperactivity.     

诱导型一氧化氮合酶和血红素氧合酶-1在百草枯中毒大鼠肾脏中的表达

目的 观察百草枯中毒大鼠肾组织中诱导型一氧化氮合酶(iNOS)和血红素氧合酶-1(HO-1)的表达,探讨其可能的病理生理机制.方法 SD大鼠84只随机分为空白对照组(A组)42只和染毒组(B组)42只.B组百草枯(25 mg/kg)、A组等量盐水腹腔注射.观察2组肾组织病理学变化及iNOS、HO-1表达,并检测HO-1 mRNA.结果 ①A组组织结构清晰.未见充血、水肿及空泡变性等病理变化;B组组织结构清晰度下降,染毒3 h即可见充血、水肿及空泡变性等病理变化,1 d达顶峰,其后缓解趋势不明显.②iNOS:A组多不表达;B组染毒后3 h在皮质部肾小管上皮细胞及肾小球内皮细胞的胞质中出现表达,随时间延长明显增强,1 d达高峰,其后维持较强表达.③HO-1与HO-1 mRNA:A组多不表达;B组染毒3 h在皮质部肾d、管上皮细胞的胞膜及胞质HO-1呈阳性表达,免疫组织化学评分(IHS)升高,HO-1 mRNA的表达增强,与A组相比差异有统计学意义(P<0.05),1 d达顶峰,之后减弱,5 d仍有阳性表达,但与A组相比,IHS差异无统计学意义(P>0.05).结论 iNOS和HO-1参与百草枯中毒肾损伤的发病过程,但其作用方式、调节途径等尚需进一步研究.     

The role of inducible nitric oxide synthase in lipopolysaccharide-mediated hyporeactivity to vasoconstrictors differs among isolated rat arteries

We investigated whether organ-specific differences exist in the role of inducible nitric oxide synthase (iNOS) in hyporeactivity to vasoconstrictors following 20 h in vitro exposure of isolated superior mesenteric, renal, hepatic and coronary arteries from the rat to bacterial lipopolysaccharide (LPS). LPS attenuated contraction in response to depolarizing KCl in all arteries. Maximum contractile responses to noradrenaline were attenuated in superior mesenteric and hepatic arteries, and those to the thromboxane A(2) analogue U46619 were attenuated in coronary arteries. LPS shifted the concentration-response curve to noradrenaline in renal arteries to the right. Removal of extracellular L-arginine improved the response to noradrenaline in superior mesenteric and renal arteries only. Addition of the iNOS inhibitor aminoguanidine resulted in full recovery of the responses to noradrenaline in superior mesenteric, renal and hepatic arteries. Contractile responses in coronary arteries did not improve after inhibition of iNOS activity. Therefore the pattern of the LPS-induced changes in vascular reactivity, as well as the contribution of iNOS to impaired vascular constriction, differed among vascular beds. These differences are likely to represent a contributory factor in the sepsis-associated redistribution of cardiac output.