Endostatin and vascular endothelial cell growth factor (VEGF) in piglet lungs: effect of inhaled nitric oxide and hyperoxia

Pulmonary hyperoxic injury manifests as widespread alveolar-epithelial and microvascular endothelial cell necrosis, resolution of which requires angiogenesis. We investigated the hypothesis that inhaled nitric oxide (iNO) and hyperoxia each decreases lung vascular endothelial growth factor (VEGF) expression but increases endostatin and that concurrent administration of both gases will show a greater effect. Piglets were randomized to breathe for 5 d room air (RA); RA + NO (RA + 50 ppm NO), O(2) (hyperoxia, F(I)O(2) >0.96), O(2) + NO, or O(2) + NO + REC (O(2) + NO plus recovery in 50% O(2) for 72 h. After the piglets were killed, we measured lung capillary leak, VEGF mRNA, VEGF, and endostatin protein in homogenates, plasma, and lavage. VEGF mRNA decreased significantly with O(2) and O(2) + NO compared with breathing RA (p < or = 0.05). VEGF protein declined in the experimental groups with a significant reduction in the recovery group compared with the RA group (p < or = 0.05). Similar but more dramatic, endostatin declined in all groups relative to the RA group (p < 0.001). Lavage fluid VEGF protein and lung capillary leak rose significantly with O(2) and O(2) + NO compared with RA, but endostatin was unchanged. At 72 h of recovery from hyperoxia, VEGF mRNA and lavage fluid VEGF but not lung VEGF protein had normalized. Hyperoxia and iNO suppresses lung endostatin expression, but iNO unlike hyperoxia alone does not alter lung VEGF production. Hyperoxia paradoxically raises lavageable VEGF levels. This latter effect and that on VEGF mRNA level but not protein is abrogated by recovery in reduced F(I)O(2) for 72 h.     

Responses of pulmonary platelet-derived growth factor peptides and receptors to hyperoxia and nitric oxide in piglet lungs

The peptides platelet-derived growth factor-A (PDGF-A) and especially -B have important roles in lung development. The effect of hyperoxic exposure with and without inhaled nitric oxide (iNO) on lung expression of PDGF and its receptors is unknown. We hypothesized that hyperoxia exposure would suppress mRNA expression and protein production of these ligands and their receptors. The addition of iNO to hyperoxia may further aggravate the effects of hyperoxia. Thirteen-day-old piglets were randomized to breathe 1) room air (RA); 2) 0.96 fraction of inspired oxygen (O2), or 3) 0.96 fraction of inspired oxygen plus 50 ppm of NO (O2+NO), for 5 d. Lungs were preserved for mRNA, Western immunoblot, and immunohistochemical analyses for PDGF-A and -B and their receptors PDGFR-alpha and -beta. PDGF-B mRNA expression was greater than that of PDGF-A or PDGFR-alpha and -beta in RA piglet lungs (p<0.05). Hyperoxia with or without iNO reduced lung PDGF-B mRNA and protein expression relative to the RA group lungs (p<0.01). PDGF-B immunostain intensity was significantly increased in the alveolar macrophages, which were present in greater numbers in the hyperoxia-exposed piglet lungs, with or without NO (p<0.01). PDGFR-beta immunostaining was significantly increased in airway epithelial cells in O2- and O2+NO-exposed piglets. PDGF-A and PDGFR-alpha immunostain intensity and distribution pattern were unchanged relative to the RA group. Sublethal hyperoxia decreases PDGF-B mRNA and protein expression but not PDGF-A or their receptors in piglet lungs. iNO neither aggravates nor ameliorates this effect.     

Modulation of pulmonary cytochrome P4501A1 expression by hyperoxia and inhaled nitric oxide in the newborn rat: implications for lung injury

Inhaled nitric oxide (iNO), with supplemental oxygen, is used in the treatment of hypoxic respiratory failure of the newborn. In this study, we tested the hypothesis that exposure of newborn rats to iNO, hyperoxia, or iNO + hyperoxia would modulate the expression of pulmonary cytochrome P450 (CYP)1A1 in relation to acute lung injury. Newborn Fischer 344 rats were maintained in room air, or exposed to iNO, hyperoxia (>95%), or iNO (20 or 40 ppm) + hyperoxia for up to 168 h, and lung injury parameters and CYP1A1 expression were studied. Animals given iNO (40 ppm) + hyperoxia were more susceptible to lung injury than those exposed to hyperoxia or iNO alone. On the other hand, animals exposed to iNO (20 ppm) + hyperoxia did not elicit lung damage. Pulmonary CYP1A1 protein and mRNA expression were induced by hyperoxia, iNO (20 or 40 ppm), or iNO (20 ppm) + hyperoxia for up to 168 h, compared with air-breathing controls. In animals given iNO (40 ppm) + hyperoxia, pulmonary CYP1A1 was enhanced at 48 h, followed by down-regulation at later time points. Immunohistochemistry experiments showed localization of CYP1A1 in the pulmonary epithelial and endothelial cells. In conclusion, because previous studies have shown beneficial effects of CYP1A1 induction in hyperoxic lung injury, our current observations showing maintenance of pulmonary CYP1A1 induction by iNO (20 ppm) + hyperoxia through the 168-h period support the hypothesis that this phenomenon may contribute to the protective effects of iNO against hyperoxic injury.     

U74389G对高氧暴露新生大鼠肺内巨噬细胞聚集和肺发育的影响

目的观察抗氧化剂-U74389G对高氧暴露新生大鼠肺内自由基产物、巨噬细胞聚集、硝基酪氨酸形成以及肺细胞增殖活性的影响,研究高氧性肺损伤发生机制及各种介质的相互关系,探讨抗氧化干预的作用.方法采用Sprague Dawley新生大鼠95%O2暴露7 d建立急性高氧肺损伤模型.应用气相色谱-质谱联用技术测定肺组织羟自由基,酶联免疫法测定脂质过氧化产物8-异前列腺烷,免疫组织化学法测定肺内巨噬细胞聚集和硝基化酪氨酸形成,3H-TdR掺入法(放射自显影)测定肺细胞增殖状况.结果 95%高浓度氧暴露可致新生大鼠严重肺损伤,肺组织羟自由基(2,3-DHBA与2,5-DHBA分别为 49.2±3.5 pmol/mg、55.8±2.3 pmol/mg)及脂质过氧化产物(8-异前列腺烷含量为546.6±32.2 pg/mg) 与空气对照组比较均显著增加 (P＜0.05),肺内巨噬细胞聚集明显,蛋白质酪氨酸发生显著硝基化,肺上皮细胞增殖停滞.抗氧化剂U74389G可降低肺组织自由基及其衍生物产生(2,3-DHBA、2,5-DHBA与8-异前列腺烷水平分别为37.9±2.4 pmol/mg、31.3±1.9 pmol/mg和358.5±24.1 pg/mg,P＜0.05),减少巨噬细胞聚集和蛋白质硝基化,肺上皮细胞增殖部分恢复,但未能显著改善高氧所致的肺实质病理形态学变化,且对正常肺细胞增殖有一定影响.结论高氧暴露通过增加肺内自由基产物及炎性细胞浸润等机制导致肺损伤,抗氧化干预可抑制或阻断其过程而具有治疗应用前景,但应充分考虑抗氧化对正常细胞增殖分化的影响.     

Inhaled nitric oxide decreases hyperoxia-induced surfactant abnormality in preterm rabbits

Inhaled nitric oxide (iNO) is a specific pulmonary vasodilator. By serving as a pro-oxidant or antioxidant, iNO may influence other pulmonary functions as well. This study was designed to test the hypothesis that iNO affects the alveolar lining after premature birth. Preterm rabbits (gestation 29 d, term 31 d) were nose-only exposed NO (14 ppm) and 98% O2, for 20 h. The others were exposed to either 98% O2 or air. In another experiment, premature rabbits were exposed to either NO in air or to air. After the exposure, bronchoalveolar lavage (BAL) was performed and the surfactant aggregates were isolated. The surfactant components and surface activity were analyzed. In total, 144 animals were studied. There were no significant differences in the number, distribution, or respiratory burst activity of cells recovered by BAL. Neither brief hyperoxia nor iNO increased plasma-derived proteins in BAL. Exposure to O2 decreased large surfactant aggregates, surface activity, and the content of surfactant protein B in BAL, whereas iNO prevented completely or partially these effects of acute hyperoxia on surfactant. Hyperoxia increased the content of malondialdehyde and decreased glutathione in epithelial lining fluid. iNO decreased malondialdehyde (p < 0.05) and tended to increase glutathione (p = 0.06) in animals breathing O2. Nitrotyrosine was not detectable in BAL, and NO2 was low in the breathing area. In room air, iNO had no significant effect on surfactant. According to the present results, a brief period of hyperoxia causes an oxidant stress and decreases the surface activity of alveolar surfactant in premature rabbits. In contrast, a low dosage of iNO decreased or prevented the O2-induced detrimental effects on alveolar surfactant and alleviated the oxidant stress.     

Independent and combined effects of prolonged inhaled nitric oxide and oxygen on lung inflammation in newborn piglets

Clinical use of nitric oxide (NO) is usually in conjunction with high oxygen concentrations, the effects of which may include lung neutrophil accumulation, apoptosis and upregulation of antioxidant enzyme activity. To define the effects of NO on neutrophils from young piglets and its relationship to lung neutrophil dynamics during hyperoxia we exposed thirty piglets to room air (RA), RA+NO (50 ppm NO), O2 (FiO2> or =0.96) or O2+NO for 5 days. Ten additional animals breathed RA+NO or O2+NO, then recovered in RA for 3 days before sacrifice. Neutrophil CD18 and intracellular oxidant production were measured by flow cytometry. Lung apoptosis were assessed by TUNEL assay. Lung myeloperoxidase, SOD and catalase were measured biochemically. When compared to RA group, there was significant reduction in neutrophil CD18 and intracellular oxidant production in the RA+NO group, but lung MPO was unchanged. The O2 and O2+NO groups did not differ in CD18 expression or in intracellular oxidant production, but had significant increase in lung myeloperoxidase compared to the RA group. Apoptosis increased significantly only in the O2+NO group. The O2 group showed significantly increased lung SOD and catalase activity compared to the RA group, whereas the RA+NO and O2+NO groups did not. We conclude that inhaled NO at 50 ppm decreases neutrophil CD18 expression as well as intracellular oxidant production. However, this effect does not impact lung neutrophil accumulation during concurrent hyperoxia. The combination of NO and O2 exposure produces an increase in lung apoptosis. Finally, NO may prevent upregulation of SOD and catalase activity during hyperoxia, potentially increasing injury.     

High-dose inhaled nitric oxide and hyperoxia increases lung collagen accumulation in piglets

Nitric oxide (NO), a pro-oxidant gas, is used with hyperoxia (O(2)) to treat neonatal pulmonary hypertension and recently bronchopulmonary dysplasia, but great concerns remain regarding NO's potential toxicity. Based on reports that exposure to oxidant gases results in pulmonary extracellular matrix injury associated with elevated lavage fluid levels of extracellular matrix components, we hypothesized that inhaled NO with or without hyperoxia will have the same effect. We measured alveolar septal width, lung collagen content, lavage fluid hydroxyproline, hyaluronan and laminin levels in neonatal piglets after 5 days' exposure to room air (RA), RA + 50 ppm NO (RA + NO), O(2) (FiO(2) > 0.96) or O(2) + NO. Matrix metalloproteinase (MMP) activity and MMP-2 mRNA were also measured. In recovery experiments, we measured lung collagen content in piglets exposed to RA + NO or O(2) + NO and then allowed to recover for 3 days. The results show that lung collagen increased 4-fold in the RA + NO piglets, the O(2) and O(2) + NO groups had only a 2-fold elevation relative to RA controls. Unlike the RA + NO piglets, the O(2) and O(2) + NO groups had more than 20-fold elevation in lung lavage fluid hydroxyproline compared to the RA group. O(2) and O(2) + NO also had increased lung MMP activity, extravascular water, and lavage fluid proteins. MMP-2 mRNA levels were unchanged. After 3 days' recovery in room air, the RA + NO groups' lung collagen had declined from 4-fold to 2-fold above the RA group values. The O(2) + NO group did not decline. Alveolar septal width increased significantly only in the O(2) and O(2) + NO groups. We conclude that 5 days' exposure to NO does not result in pulmonary matrix degradation but instead significantly increases lung collagen content. This effect appears potentially reversible. In contrast, hyperoxia exposure with or without NO results in pulmonary matrix degradation and increased lung collagen content. The observation that NO increased lung collagen content represents a new finding and suggests NO could potentially induce pulmonary fibrosis.     

Monocyte chemoattractant protein-1 and its receptor CCR-2 in piglet lungs exposed to inhaled nitric oxide and hyperoxia.

Monocyte chemoattractant protein-1 (MCP-1), acting through its C-C chemokine receptor 2 (CCR-2), has important roles in inflammation, angiogenesis, and wound repair. The individual and combined effects of inhaled nitric oxide (NO) and hyperoxia on lung MCP-1 and CCR-2 in relation to lung leukocyte dynamics are unknown. Because MCP-1 gene is up-regulated by oxidants, we hypothesized that inhaled NO with hyperoxia will increase MCP-1 production and CCR-2 expression more than either gas alone. We randomly assigned young piglets to breathe room air (RA), RA+50 ppm NO (RA+NO), O(2), or O(2)+NO for 1 or 5 d before sacrifice. Lungs were lavaged and tissues preserved for hybridization studies, Western blotting, histology, and immunohistochemistry. The results show that lung MCP-1 production and alveolar macrophage count were significantly elevated in the 5-d O(2) and O(2)+NO groups relative to the RA group (p < or = 0.05). In contrast, lung CCR-2 abundance was diminished in the O(2) group (p 相似文献   

实验性胎粪吸入性肺炎一氧化氮吸入干预的研究

目的探讨在不同氧浓度下吸入CD11b不同浓度一氧化氮(nitric oxide, NO)对实验性胎粪吸入性肺炎肺损伤及肺中性粒细胞表面粘附分子CD11b表达的影响,为对该病是否适宜早期NO吸入干预提供实验室依据.方法建立胎粪吸入性肺炎模型兔,对常频机械通气下的胎粪吸入性肺炎家兔在21%或100%的氧浓度下分别给予6×10-6、10×10-6、20×10-6的NO干预12 h,通过图像分析处理测量肺泡间隔平均距离,病理切片检查评估肺损伤程度;测定肺组织髓过氧化物酶(myeloperoxidase, MPO)活性,并采用流式细胞术检测肺泡灌洗液中性粒细胞表面粘附分子CD11b的表达.结果在相同氧浓度下,NO吸入能显著改善氧合.病理结果表明,各干预组和非干预组均可见严重的中性粒细胞浸润到肺间质,轻到中度的肺出血、肺水肿、肺透明膜形成以及中性粒细胞移行到肺泡腔,各吸入NO干预组上述病理变化均有减轻趋势.相同氧浓度下10×10-6、20×10-6的NO 吸入干预组肺MPO活性分别显著低于非干预组(P均<0.05);100%氧浓度下20×10-6NO干预组MPO活性显著低于21%氧浓度下同一NO干预组[(1.4±0.3) U/g vs (2.0±0.1) U/g,P<0.05].在21%或100%氧浓度下,10×10-6、20×10-6NO干预组与非干预组间肺泡灌洗液中性粒细胞CD11b的表达(平均荧光强度)差异显著,表现为NO吸入后CD11b表达显著降低(P均<0.05);在不同氧浓度下同一NO浓度干预组之间差异均无显著意义.各组肺泡间隔距离及肺湿/干重比、平均动脉压差异无显著意义,高铁血红蛋白含量在正常范围之内. 结论 NO吸入可以通过抑制肺组织中性粒细胞粘附分子CD11b的表达而减轻中性粒细胞在肺组织的扣留及MPO的活性,起到潜在的抗炎作用.对胎粪吸入性肺炎,早期吸入NO进行干预可望减轻肺损伤,其合适的NO吸入浓度可能是(10～20)×10-6.     

肺表面活性物质和吸入一氧化氮治疗家兔胎粪吸入性肺损伤

目的　观察在应用肺表面活性物质 (Surf)和吸入一氧化氮 (NO)预防性治疗家兔胎粪吸入性急性肺损伤 (ALI)并机械通气时的疗效。方法　将 3 3只成年家兔随机分为 5组进行治疗 :即对照组 (C ,n =8)、NO组 (n =6)、Surf组 (n =7)、NO +Surf组 (SNO ,n =6)、正常组 (N ,n =6)。前四组用胎粪生理盐水混悬液滴入气道内经机械通气造成ALI并随机分四组治疗 ;N组气道内滴入生理盐水替代 ;NO组连续吸入NO 1× 10 - 6 、10× 10 - 6 、2 0× 10 - 6 、40× 10 - 6 各 1h ,间隔停用 3 0min ;Surf组气道内滴入猪肺Surf10 0mg/kg ;SNO组联合NO吸入及Surf组治疗 ,各组均治疗 6h ,同时测定血气、肺呼吸力学判断疗效。化学发光法检测吸入气NO浓度。结果　在C组胎粪滴入 3 0min后动脉血氧合 (PaO2 /FiO2 )及呼吸顺应性 (DynamicCompliance ,Cdyn)显著变差 ,治疗后血氧合、Cdyn在SNO组显著改善 ,Surf和NO组略有改善。在湿化器前持续接入NO可在供气管道“Y”近端测得较为稳定的吸入NO浓度 ,受呼出气的影响最小 ,( 10～ 2 0 )× 10 - 6 NO吸入有较好的效果。结论　Surf联合NO治疗在有效预防ALI上优于单独应用Surf或NO。从呼吸机供气管路持续接入NO测定到稳定NO浓度与接入气和监测部位有关     

The production of hydroxyl radicals in the fetal lamb brain resulting from occlusion of the umbilical circulation and the transplacental effect of MCI-186 to inhibit hydroxyl radical production

The present study evaluated hydroxyl radical production in fetal lamb brain during and after umbilical cord occlusion and examined the effects of injecting MCI-186 (3-metyl-1-phenyl-2-pyrazolin-5-one; Edaravone), a hydroxyl radical scavenger, into the maternal circulation. In 11 chronically instrumented lambs, intermittent total umbilical cord occlusions 1 min out of every 3 min for 1 h and 10-min persistent total umbilical cord occlusion were performed with brain microdialysis using 5 mM of sodium salicylate. In the remaining four lambs, 60 mg of MCI-186 was administered into the maternal circulation from shortly before the end of 10-min persistent total umbilical cord occlusion. Concentrations of 2,3-dihydroxy-benzoic acid (2,3-DHBA), produced by hydroxyl radical reactions with sodium salicylate, were measured in perfusate by HPLC. Concentration of 2,3-DHBA in perfusate was 23.05 +/- 10.95 nM before umbilical cord occlusion. Levels of 2,3-DHBA tended to increase slightly during and after intermittent umbilical cord occlusion, and were significantly increased by the end of 10-min occlusion (40.06 +/- 21.36 nM) and after occlusion (93.74 +/- 29.17 nM). Infusion of MCI-186 suppressed 2,3-DHBA concentration to 29.35 +/- 14.95 nM after occlusion. Administration of MCI-186 into the maternal circulation reduces hydroxyl radical production induced by umbilical cord occlusion in the fetal lamb brain.     

Inhaled nitric oxide enhances distal lung growth after exposure to hyperoxia in neonatal rats

Exposure of newborn rats to hyperoxia impairs alveolarization and vessel growth, causing abnormal lung structure that persists during infancy. Recent studies have shown that impaired angiogenesis due to inhibition of vascular endothelial growth factor (VEGF) signaling decreases alveolar and vessel growth in the developing lung, and that nitric oxide (NO) mediates VEGF-dependent angiogenesis. The purpose of this study was to determine whether hyperoxia causes sustained reduction of lung VEGF, VEGF receptor, or endothelial NO synthase (eNOS) expression during recovery, and whether inhaled NO improves lung structure in infant rats after neonatal exposure to hyperoxia. Newborn rat pups were randomized to hyperoxia [fraction of inspired oxygen (Fio(2)), 1.00] or room air exposure for 6 d, and then placed in room air with or without inhaled NO (10 ppm) for 2 wk. Rats were then killed for studies, which included measurements of body weight, lung weight, right ventricular hypertrophy (RVH), morphometric analysis of alveolarization (by mean linear intercept (MLI), radial alveolar counts (RAC), and vascular volume (Vv), and immunostaining and Western blot analysis. In comparison with controls, neonatal hyperoxia reduced body weight, increased MLI, and reduced RAC in infant rats. Lung VEGF, VEGFR-2, and eNOS protein expression were reduced after hyperoxia. Inhaled NO treatment after hyperoxia increased body weight and improved distal lung growth, as demonstrated by increased RAC and Vv and decreased MLI. We conclude that neonatal hyperoxia reduced lung VEGF expression, which persisted during recovery in room air, and that inhaled NO restored distal lung growth in infant rats after neonatal hyperoxia.     

吸入一氧化氮对感染性急性肺损伤时红细胞变形能力的影响

目的 研究吸入一氧化氮(NO)对红细胞变形能力的影响及其可能机制.方法 将3～4周龄健康雄性幼猪30只麻醉后经口气管插管进行机械通气,随机分为4组.(1)正常组(C,n=6)单纯机械通气;(2)正常幼猪加吸入NO(CNO,n=4);(3)模型组(M,n=10)单纯机械通气;(4)模型制备加吸入N0(MNO,n=10).M和MNO组动物经腹腔注射标准大肠杆菌诱发急性肺损伤(ALI),C及CNO组用无菌生理盐水替代.MNO组出现ALI后进行吸入NO(10×10-6),治疗24h,CNO组则机械通气4 h后(0 h)开始吸入NO并维持24 h.在实验基础状态、ALI时(0 h)、ALI后12以及24 h测血细胞比容、全血黏度、红细胞膜Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性及红细胞内丙二醛(MDA)浓度.结果 CNO组吸入NO后12、24 h高切率下血液黏度(反映红细胞变形能力)、红细胞膜Na+-K+-ATP酶、Ca2+-Mg2+-ATP酶活性及红细胞内MDA浓度变化不大.动物出现ALI时其红细胞变形能力降低,红细胞膜Ca2+-Mg2+-ATP酶、Na+-K+-ATP酶活性均下降,红细胞内MDA浓度升高(P＜0.05).MNO组在吸入NO 12 h时红细胞变形能力改善,红细胞膜Ca2+-Mg2+-ATP酶、Na+-K+-ATP酶活性均较M组高(P＜0.05),红细胞内MDA浓度则低于M组(P＜0.05);但这些参数在吸入NO 24 h与C组比较差异均无显著性(P＞0.05).结论 ALI时红细胞变形能力显著下降,可以因吸入NO而改善,但作用不持久.     

SB265610抗炎症干预在新生大鼠高氧肺损伤中的抗氧化作用

目的：探讨受体拮抗剂SB265610干预中性粒细胞（PMN）趋化作用后，高氧暴露新生大鼠肺部自由基产生情况。方法：采用600mL/LO2建立新生大鼠高氧暴露支气管肺发育不良模型（BPD）；新生大鼠随机分为4组：空气对照组，空气＋SB265610组，高氧对照组，高氧＋SB265610组；通过免疫组织化学和支气管肺泡灌洗液（BALF）细胞计数检测肺部中性粒细胞趋化因子、细胞因子诱导的中性粒细胞趋化因子-1（CINC-1）表达和炎性细胞聚集的情况；应用气相色谱-质谱（CC-MS）联用技术测定肺组织羟自由基；酶联免疫法测定脂质过氧化产物8-异前列腺烷。结果：高氧对照组新生大鼠肺内巨噬细胞、支气管和肺泡上皮细胞中CINC-1表达水平升高，同时WBC和PMN计数较空气对照组显著增加（Pa〈0．01）；高氧对照组新生大鼠肺中羟自由基水平显著高于空气对照组（P〈0．01），SB265610处理后高氧暴露鼠肺组织羟自由基水平明显下降（P〈0、01）；高氧对照组新生大鼠肺组织8-异前列腺烷水平显著升高，SB265610处理后明显降低（P〈0．01）。结论：抗PMN趋化干预可明显降低新生大鼠高氧肺损伤过程中肺内羟自由基及脂质过氧化水平。     

常频通气联合一氧化氮吸入治疗新生儿持续肺动脉高压

目的 探讨常频通气联合一氧化氮吸入(iNO)治疗新生儿持续肺动脉高压(PPHN)的疗效.方法 对22例确诊为PPHN且入院时采取常频通气疗效不满意的患儿给予iNO.NO初始吸入浓度上,20例为(10～20)×10-6,2例为(20～40)×10-6.当SpO2≥93%并已经稳定20min以上,开始下调呼吸机参数,并逐渐下调NO吸入浓度.当NO吸入浓度降至(5～10)×10-6时,再持续2～3h后,若PaO2>55mm Hg(1 mm Hg=0.133 kPa)、SpO2>93%时停止吸入.在NO吸入前和吸入后1～6 h分别进行血气分析,连续记录生命体征、SpO2和监测NO2值等.结果 20例在吸人NO后5～20 min左右SpO2逐渐升高,临床缺氧状态逐步改善.有效率达91%.吸入NO 1～6 h,SpO2、PaO2分别由吸入前的(76.3±13.3)%、(46.4±10.1)mm Hg升到(94.4±2.9)%和(92.8±24.7)mm Hg,FiO2由(0.9±0.1)降至(0.6±0.1),差异均有非常显著性(P<0.001).患儿生命体征平稳,未发现急性合并症.全组治愈18例,治愈率达82%,自动放弃4例.结论 iNO能有效地缓解PPHN患儿的乏氧状态.提高氧分压和治愈率.NO吸入不良反应小、易操作.iNO初始吸人浓度以(10～20)×10-6开始为宜,极个别病例可以(20～40)×10-6开始.     

洛沙坦对高氧致慢性肺疾病新生大鼠肺纤维化的影响

目的：血管紧张素II除了调节血压,还参与肺纤维化的发生。研究血管紧张素II 1型受体拮抗剂洛沙坦对高氧致慢性肺疾病（CLD）新生大鼠肺组织的影响,探讨洛沙坦在抗纤维化的作用及可能的机制。方法：将Waistar新生大鼠生后24 h内随机分为：空气组、高氧组、高氧+注射用水组、高氧+ 洛沙坦组,高氧组氧浓度为85%~90%,高氧+注射用水组、高氧+洛沙坦组在生后6 d每天用注射用水或洛沙坦(5 mg/kg)灌胃至实验结束,于7,14,21 d处死。观察病理组织学改变;生化检测肺组织超氧化物歧化酶活性(SOD)、丙二醛(MDA)和羟脯氨酸(HYP)的含量。结果：高氧暴露后大鼠肺泡数目减少,终末气腔扩张,次级隔数目减少,肺泡间隔显著增厚,甚至出现肺出血和肺实变。洛沙坦干预后肺泡间隔变薄,但肺泡腔没有明显缩小,且肺泡次级隔仍较少。高氧后14和21 d新生大鼠肺组织HYP含量较同期空气组显著增加(P<0.01),洛沙坦治疗2周后肺组织HYP含量较高氧组明显下降 (471.46±30.63 μg/kg vs 545.15±34.90 μg/kg, P<0.01); 高氧组在高氧暴露7 d时,SOD活力呈代偿性增加,之后逐渐下降至空气组水平;MDA水平在高氧暴露后显著增加,但随日龄增加呈下降趋势。洛沙坦治疗能增加高氧肺组织SOD的活力, 21 d时差异有显著性(82.94±4.62 U/mg protein vs 67.78±8.02 U/mg protein, P<0.01),同时降低MDA的水平(30.54±5.89 nmol/mg protein vs 48.75±8.09 nmol/mg protein, P<0.01)。结论：洛沙坦治疗能减轻高氧诱导新生鼠CLD肺纤维化的程度,该过程可能与肺组织抗氧化酶活性增加以及膜脂质过氧化减轻密切相关。［中国当代儿科杂志,2007,9（6）：591-594］     

一氧化氮吸入对新生鼠高氧肺损伤时表面活性蛋白A和肺甘露糖结合力的影响

目的：通过观察吸入一氧化氮(iNO)对新生大鼠高氧肺损伤时表面活性蛋白A(SP-A)和肺组织甘露糖结合力(MBA)的影响,探讨iNO对高氧肺损伤保护作用的可能机制。方法：新生大鼠随机分为对照组(空气);高氧组(>95%O2,6d);NO组(空气+10ppmNO,24h);高氧+NO组(>95%O2,6d+10ppmNO,24h)。观察暴露后2d和6d肺组织病理变化,肺SP-AmRNA基因表达、蛋白含量和MBA的变化。结果：高氧组病理损伤明显,暴露后2d时SP-A的mRNA含量(0.81±0.04vs1.53±0.25)和蛋白表达(59.45±18.37vs89.77±16.41)比对照组减少,6d时分别比对照组增加(0.81±0.02vs0.63±0.03),(93.57±13.71vs47.73±21.69),(P<0.05)。高氧+NO组暴露后2d时病理损伤比高氧组明显减轻,SP-AmRNA(0.55±0.91)比对照组和高氧组降低,SP-A蛋白表达(55.12±17.53)比对照组降低(P<0.01);6d时SP-A蛋白表达(67.33±18.59)比高氧组降低(P<0.05)。甘露糖结合力在暴露后2d时NO组比对照组增加(0.821±0.133vs0.580±0.158)、高氧+NO组比高氧组增加(0.430±0.175vs0.738±0.141)(P<0.05)。结论：小剂量NO吸入可降低高氧肺组织SP-A蛋白表达的升高,增加肺组织的MBA,减轻肺组织的病理损伤。     

多西环素对新生鼠高氧肺损伤影响的体视学研究

目的 探讨非特异性金属基质蛋白酶抑制剂多西环素(Doxycycline)对高氧肺损伤肺形态学的影响.方法 新生SD大鼠生后12 h内随机分为4组:空气+生理盐水组(AN组)、空气+多西环素组(AD组)、高氧+生理盐水组(ON组)、高氧+多西环素组(OD组).高氧组(ON、OD组)大鼠于90%氧气条件下饲养.多西环素组(AD、OD组)每天早晚两次经胃管喂人多西环素20 mg/(kg·次),喂药至实验日或生后14 d.1、3、7、14及21 d进行肺组织切片的体视学研究.结果 高氧及多西环素均导致平均肺泡面积增加,14 d OD组星体积高于同期ON组.除ON组外,各组肺泡间隔均逐渐增厚,氧气和多西环素共同作用增加肺泡间隔厚度,且作用持续.单纯高氧使肺问质胶原含量明显增加;高氧合并多西环素作用早期胶原含量较AN组增加明显,14 d后胶原含量降低并与AN组相近.结论 高氧和(或)多西环素均影响肺发育,多西环素可减少高氧导致的肺间质中胶原比例增加.     

Inhaled nitric oxide attenuates hyperoxic lung injury in lambs

Cytochrome P450 (CYP) inhibition with cimetidine reduces hyperoxic lung injury in young lambs. Nitric oxide (NO), also a CYP inhibitor, has been shown to either aggravate or protect against oxidant stress depending on experimental context. The objective of this study was to determine whether NO, like cimetidine, would protect young lambs against hyperoxic lung injury, and whether its effect was associated with CYP inhibition. Three groups of lambs were studied: 1) room air exposure, 2) >95% O2, and 3) >95% O2 plus inhaled NO. After 72 h, hyperoxia alone resulted in a significant increase in arterial P(CO2) and number of polymorphonuclear leukocytes in bronchoalveolar lavage (BAL), and a significant decrease in arterial/alveolar O2 tension (a/A). The addition of inhaled NO significantly decreased the hypercarbia and BAL polymorphonuclear cellular response associated with hyperoxia but had no beneficial effect on a/A ratio. There were no significant differences in F2-isoprostanes or isofurans (markers of lipid peroxidation) measured in BAL or lung tissue among study groups. No intergroup differences were detected in BAL epoxyeicosatrienoic acid levels (index of CYP activity). The results of this study indicate that hypercarbia and inflammation accompanying hyperoxic lung injury in young lambs can be attenuated by inhaled NO. However, this study provides no direct evidence that NO is inhibiting CYP-mediated oxidant lung injury.