维甲酸对新生大鼠高氧肺损伤的保护作用

新生儿支气管肺发育不良 (bronchopumonarydysplasia ,BPD)是与早产、感染及长期吸入高浓氧有关的严重慢性肺疾病。目前临床多采用地塞米松预防和治疗BPD ,该药虽有助于患儿早日脱离气管插管 ,但由于其可引起血压升高、消化道出血、脑及肺发育受阻等副作用 ,而限制了其在临床的应用[1 ] 。近年研究发现 ,极低出生体重儿BPD的病理改变以肺发育受阻为主 ,表现为肺泡隔形成受阻和肺泡化降低[2 ] 。维甲酸 (retinoicacid ,RA)可降低维生素A缺乏的早产儿BPD的发病率 ,显著提高新生大鼠由于使用地塞米松而降低了的肺泡化水平[3] 。本实验通…     

维甲酸对高氧暴露下新生大鼠肺组织中Ⅰ型胶原含量的影响

为探讨维甲酸对高氧暴露下新生大鼠肺组织中Ⅰ型胶原含量的影响。将生后2d的SD大鼠随机分为4组：（1）空气 生理盐水组；（2）高氧 生理盐水组；（3）高氧 地塞米松组；（4）高氧 维甲酸组。（2），（3）和（4）组持续暴露于85%O2中，于生后14d采用免疫组化和原位杂交方法对肺组织中Ⅰ型胶原蛋白，转化生长因子βⅠ，Ⅱ型受体，肺组织中Ⅰ型胶原mRNA行定位，半定量检测，作HE染色行辐射状肺泡计数，结果显示，与高氧 生理盐水组相比，高氧 维甲酸组辐射状肺泡计数显著增加，肺组织中Ⅰ型胶原蛋白表达明显增强，而Ⅰ型胶原基因表达和转化生长因子βⅠ，Ⅱ型受体表达显著减弱，阳性表达明显改变的分布主要在支气管上皮细胞，肺泡上皮细胞和肺内间质细胞，提示维甲酸通过对Ⅰ型胶原mRAN转录后调控和调节Ⅰ型腾的蛋白的降解而啬 肺内胶原含量，从而起到逆转高氧对肺发育抑制作用。     

维甲酸、血小板衍生生长因子对早产新生大鼠高浓度氧肺损伤的影响

目的观察维甲酸（RA）和血小板衍生生长因子（PDGF）对高浓度氧（简称高氧）抑制早产新生大鼠肺发育的影响，探讨其作用机制。方法1日龄早产SD大鼠随机分为：空气＋生理盐水组（Ⅰ组）、高氧＋生理盐水组（Ⅱ组）、空气＋RA组（Ⅲ组）、高氧＋RA组（Ⅳ组）。Ⅱ、Ⅳ组持续暴露于85％氧气中。Ⅲ、Ⅳ组每目腹腔注射RA500μg／kg，Ⅰ、Ⅱ组注射相同剂量的生理盐水。应用RT—PCR和免疫组织化学法检测各时间点（生后4、7、10、14及21d）各组大鼠肺组织PDGFmRNA和蛋白表达水平。结果随日龄的增加，PDGF—A、-B mRNA及蛋白表达发生不同的变化。与Ⅰ组比较，高氧暴露下PDGF-B mRNA和蛋白表达显著增高（P〈0．05），但PDGF-A mRNA及蛋白表达却显著降低（P〈0．05）。RA上调PDGF—A mRNA及蛋白表达（P〈0．05），但对PDGF—B mRNA及蛋白表达作用不显著（P〉0．05）。结论高氧暴露下，PDGF—AmRNA及蛋白表达受抑，PDGF—BmRNA及蛋白表达增强。PDGF-A、-B共同参与了高氧暴露下肺组织损伤过程。RA上调PDGF—AmRNA及蛋白表达，能部分逆转高氧引起的肺损伤。     

茶碱减少肺泡间隔厚度以改善高氧暴露新生大鼠肺发育的研究(英文)

目的明确高氧暴露新生大鼠肺组织的肺泡间隔增厚是否由肺泡间隔细胞凋亡抑制引起,进一步研究茶碱是否可以通过减少肺泡间隔厚度改善高氧暴露新生大鼠的肺发育。方法建立新生SD大鼠高氧暴露(85%O2)肺损伤模型,将新生大鼠随机分为3组。①新生大鼠每日注射生理盐水并予高氧暴露;②新生大鼠每日注射生理盐水并置正常空气中;③新生大鼠注射茶碱20 mg/(kg.d)并予高氧暴露。并运用TUNEL法检测肺泡间隔中的凋亡细胞,用免疫组织化学技术检测肺泡间隔中的肌成纤维细胞。结果高氧暴露7 d的新生大鼠肺组织肺泡间隔增厚,肺泡间隔细胞凋亡减少,肺泡间隔肌成纤维细胞数量增加;而茶碱可以使高氧暴露后新生大鼠肺组织肺泡间隔细胞变薄,肺泡间隔细胞凋亡增加,肺泡间隔肌成纤维细胞减少。结论茶碱可以通过减少肺泡间隔厚度,减少肺泡间隔内的肌成纤维细胞数量,进而改善高氧暴露新生大鼠的肺发育。增加肺泡间隔细胞凋亡可能是茶碱的作用机制之一。肌成纤维细胞作为一种重要的间质细胞,可能在高氧引起的肺泡间隔细胞凋亡异常及肺泡间隔增厚等变化中起重要作用。[临床儿科杂志,2010,28(12):1101-1107]     

维甲酸治疗新生大鼠高氧肺发育受抑对肺组织基质金属蛋白酶及其组织抑制剂表达的影响

目的 观察维甲酸(RA)对高氧抑制肺发育的影响,初步探讨其作用机制。方法 新生SD大鼠生后d2随机分为I空气+生理盐水组,Ⅱ高氧+生理盐水组,Ⅲ空气+RA组,Ⅳ高氧+RA组。Ⅱ、Ⅳ组持续暴露于85％氧气中,Ⅲ、Ⅳ组每日腹腔注射RA500μg/kg。生后14d行肺组织病理学检查,辐射状肺泡计数(RAC)和免疫组化法检测基质金属蛋白酶(MMP-2、MMP-9)及其组织抑制剂(TIMP-1、TIMP-2)的表达。结果Ⅱ、Ⅳ组肺组织显示肺泡生成受抑,RAC分别较I、Ⅲ组显著减少(P<0.01),但Ⅳ组RAC(8.3±0.8)较Ⅱ组(7.2±0.9)明显增加(P<0.01)。Ⅱ、Ⅳ组MMP-2、MMP-9、TIMP-1和TIMP-2的表达较I、Ⅲ组明显增强(P<0.01),但Ⅳ组MMP-2、MMP-9的表达(2.70±0.65,2.64±0.48)较Ⅱ组(3.36±0.59,3.04±0.72)减弱(P<0.05),而TIMP-1的表达(3.68±0.51)较Ⅱ组(3.32±0.63)增强(P<0.05),TIMP-2的表达无统计学差异。结论 RA可部分阻止高氧引起的肺发育进程阻滞,可能是通过纠正MMPs/TIMPs的失衡而发挥作用的。     

重组人胰岛素样生长因子1对高氧暴露下新生大鼠肺组织Clara细胞分泌蛋白表达的影响

目的探讨重组人胰岛素样生长因子1（rh-IGF-1）对高氧暴露下的新生大鼠肺损伤的影响。方法将生后2d的Wistar大鼠80只,随机分为4组。Ⅰ组：空气组;Ⅱ组：高氧组;m组：空气＋rh-IGF-1组;Ⅳ组：高氧＋rh-IGF-1组。Ⅱ组和Ⅳ组大鼠持续暴露于85％O2中,Ⅰ组和Ⅲ组大鼠呼吸空气。Ⅲ组和Ⅳ组从第3天起每日腹腔注射rh—IGF-1,1μ/Kg。于高氧暴露后7d取肺组织,用免疫组化方法检测肺内CC10表达变化,用TUNEL方法检测肺细胞凋亡。结果免疫组化结果阳性染色主要分布于终末及呼吸性细支气管上皮细胞。Ⅱ组终末和呼吸性细支气管上皮Clara细胞占上皮细胞的百分率（32．17±3．19）％和免疫阳性强度（29．45±5．56）,均明显少于Ⅰ组的测定值（68．32±2．04）％和（42．37±3．24）,差异均有统计学意义（P〈0．01）;Ⅱ组肺组织细胞凋亡指数（55．77±6．09）％明显高于Ⅰ组的测定值（16．41±4．01）％,差异有统计学意义（P〈0．01）;Ⅳ组的Clara细胞百分率（52．98±2．68）％和免疫阳性强度（41．22±6．36）较Ⅱ组明显增加,Ⅳ组的细胞凋亡指数（27．98±3．09）％明显低于Ⅱ组的测定值,差异均有统计学意义（P〈0．01）。而Ⅰ组与Ⅲ组之间差异无统计学意义（P〉0．01）。结论高氧诱导肺细胞凋亡、抑制肺内CC10分泌,而rh-IGF-1通过抑制肺细胞凋亡,能够有效抑制CC10分泌的减少,减轻气道炎症反应,抑制肺泡化阻滞,对高氧性肺损伤起保护作用。     

高氧暴露早产大鼠肺泡上皮细胞损伤与细胞外基质变化的动态研究

目的 动态观察高氧暴露新生早产大鼠肺组织肺泡上皮细胞(AEC)超微结构与细胞外基质(ECM)的变化,探讨其在高氧性肺损伤肺纤维化发病机制中的作用.方法 将80只新生早产SD大鼠随机分为空气组和高氧组,空气组在空气中饲养,高氧组置于高氧箱(保持氧体积分数>950 nd/L)中饲养,每组40只;每组又随机分为3、7、14、21 d 4个亚组,每组10只.分别在第3、7、14、21天处死动物,收集肺组织标本.采用透射电镜观察各亚组大鼠AEC超微结构改变;采用碱水解法测定其肺组织匀浆羟脯氨酸(HYP)含量;采用免疫组织化学方法检测肺组织Ⅰ型与Ⅲ型胶原表达与分布;并用图像分析方法检测肺组织Ⅰ、Ⅲ型胶原阳性表达的PU值.结果 高氧组第3天即出现AEC轻度损伤;第7天时AEC损伤加重,第14、21天时出现AEC-Ⅱ坏死,板层小体基本排空,AEC基底膜及气血屏障明显增厚,肺间质可见大量胶原原纤维.肺组织HYP含量随着高氧暴露时间的延长而逐渐增加,第21天时达最高,在第7、14、21天时均明显高于空气组.Ⅰ、Ⅲ型胶原均在第3天呈弱阳性表达,第14、21天呈强阳性表达.肺组织Ⅰ、Ⅲ型胶原阳性表达的PU值在第14、21天时明显高于空气组(P<0.01).结论 AEC损伤是早产大鼠长时间高氧暴露所致肺损伤的早期特征,而后期以肺间质ECM过度沉积为主.     

CXCR2 blockade reduces radical formation in hyperoxia-exposed newborn rat lung

Inflammation contributes greatly to the pathogenesis of bronchopulmonary dysplasia. In previous studies, we showed that blocking neutrophil influx by treatment with SB265610, a selective CXCR2 antagonist, could partly reduce superoxide accumulation and preserve alveolar development in 60% O(2)-exposed newborn rats. The purpose of this study was to further investigate the role of neutrophils in the formation of reactive oxygen and nitrogen species mediating hyperoxia-impaired lung development. We found that hydroxyl radical formation and lipid peroxidation in rat lungs were significantly increased during 60% O(2) exposure. These increases were attenuated by the administration of SB265610. In addition, SB265610 largely inhibited protein nitration induced by hyperoxia. SB265610 partly prevented the hyperoxia-enhanced bronchoalveolar lavage (BAL) protein content in 60% O(2)-exposed animals. Our results demonstrate that neutrophils have a pivotal role in hydroxyl radical formation, lipid peroxidation and protein nitration. Taken together with our previous studies, the present findings show that blocking neutrophil influx protects alveolar development and improves lung function in part by preventing reactive oxygen/nitrogen species accumulation.     

地塞米松对高氧肺损伤新生大鼠肺水通道蛋白1表达的影响

目的 探讨地塞米松对新生大鼠高氧肺损伤时水通道蛋白1(AQP1)表达的影响及其对肺损伤的可能保护机制.方法 新生Wistar大鼠32只随机分为空气组、高氧组、空气+地塞米松组、高氧+地塞米松组.第3天取肺组织,采用逆转录-聚合酶链反应(RT-PCR)和免疫组织化学法检测AQP1的mRNA表达和分布变化;并对肺湿/干重比(W/D)、支气管肺泡灌洗液(BALF)中的蛋白含量、肺通透指数及组织病理学改变进行对比分析.结果 高氧暴露第3天肺组织出现出血、炎性细胞浸润和水肿,肺W/D、BALF蛋白含量、肺通透指数明显升高;地塞米松干预组肺损伤程度减轻,测定值降低.空气组、高氧组、高氧+地塞米松组AQP1 mRNA相对吸光度比值分别为0.70±0.04、0.42±0.03、1.04±0.04,各组间差异有显著性(P<0.05);与空气组相比,高氧组AQP1 mRNA表达明显降低,高氧+地塞米松组AQP1 mRNA表达显著上调;AQP1蛋白表达与其mRNA变化一致.结论 高氧肺损伤时大鼠肺AQP1表达下调;地塞米松干预对肺损伤有保护作用,上调肺AQP1的表达可能是其作用机制之一.     

地塞米松、维甲酸对大鼠肺发育的影响及与胰岛素样生长因子关系

目的探索地塞米松(Dex)、维甲酸(RA)对大鼠肺发育的影响及其与胰岛素样生长因子(IGF)_Ⅰ、(IGF)_Ⅱ的关系。方法将80只SD孕鼠分为4组,即对照组(A组)、Dex1组(B组)、Dex2组(C组)、RA组(D组)。A、B、D组于孕18～20d分别皮下注射生理盐水、Dex,腹腔注射RA,C组于生后1～3d皮下注射Dex。各组于孕18、20、21d(C组孕期不取)、生后1、3、5、7、10、14、21d取肺标本作病理学检查、辐射状肺泡计数(RAC)、IGF_Ⅰ、IGF_Ⅱ多肽或mRNA之肺表达强度。结果①形态学及肺表达:B、C组早期肺泡发育提前(数目多,壁薄),晚期则腔大数少;IGF_Ⅰ主要表达于肺胞分隔期(生后4～10d),A、D组等肺泡发育时,IGF_Ⅰ呈强阳性表达,其他各组或时间点则呈弱阳性或阴性表达;IGF_Ⅱ的表达主要见于出生前支气管,小血管等管道组织,受Dex等影响较小。②Westernblot结果:IGF_Ⅰ多肽的表达:A组生后5～7d达高峰,随后渐降低;B组孕20d～生后3d,各时间点强度明显高于A组(P<0.01),以后均低于A组(P<0.01);C组晚期强度明显低于A组(P<0.01);D组各时间点浓度明显高于A组(P<0.01)。IGF_Ⅱ多肽的表达:各组孕18d最高,随后渐降低直至微量。③RT_PCR结果:IGF_Ⅰ、IGF_ⅡmRNA表达的强度变化与各自的肽浓度变化相似。结论IGF_Ⅰ、IGF_Ⅱ与肺发育过程有密切关系,IGF_     

Effect of retinoic acid on renal development in newborn mice treated with an angiogenesis inhibitor

Background: A mouse model of impaired renal development was developed and the effect of retinoic acid (RA) was investigated in this animal model. Methods: An angiogenesis inhibitor (SU1498) was injected s.c. into day 3 C57BL/6 newborn mice to create a model of arrested renal development. RA (2 mg/kg) was injected i.p. for 10 days. Morphometry and immunohistochemistry were done. Results: Mice injected with SU1498 demonstrated deranged renal development in tubular structure and glomerular tuft area. Cortical thickness and area of glomerular tuft were significantly decreased after vascular endothelial growth factor (VEGF) inhibitor, and were significantly restored by RA. The length of capillary loops/glomerulus, the number of podocytes/glomerulus, and density of peritubular capillaries on CD31 immunostaining were significantly decreased by VEGF blocking and recovered by RA. Conclusions: VEGF plays a major role in renal development, and RA reverses the inhibited development caused by an angiogenesis inhibitor.     

孕鼠叶酸缺乏对幼鼠肺发育及其SP-A变化的研究

目的：研究孕鼠叶酸缺乏对幼鼠肺发育的影响及幼鼠SP-A基因表达的变化,探讨孕鼠叶酸缺乏引起幼鼠肺发育障碍的发病机制。方法：成熟雌性Sprague-Dawley大鼠36 只随机分为实验组和对照组（各18只）,分别喂以缺乏叶酸和添加叶酸的纯合饲料。2 周后与雄性大鼠交配,分别于生后1、7、14 d留取幼鼠肺组织标本。苏木精-伊红染色观察肺组织病理改变,免疫组化检测肺组织SP-A蛋白表达,实时荧光定量RT-PCR技术检测SP-A mRNA表达。结果：与对照组比较,实验组幼鼠肺组织结构紊乱。实验组幼鼠SP-A阳性的Ⅱ型细胞免疫组化染色平均光密度从第1天到第14天逐渐减少,与对照组第1天至第14天比较差异有统计学意义（P<0.05）。RT-PCR检测表明实验组幼鼠SP-A mRNA从第1 天到第14 天逐渐减少,与对照组第1 天至第14天比较差异有统计学意义（P<0.05）。结论：孕期叶酸缺乏能影响新生大鼠肺组织SP-A的表达,从而可能导致肺成熟障碍。     

Effects of retinoic acid on the neural crest-controlled organs of fetal rats

Prenatal exposure of rat embryos to retinoic acid induces severe malformations involving various organs. The mechanisms of this embryopathy are known only in part. This study describes the malformations of the neural crest-derived organs in this model and shows that many of them fit into the pattern of disturbed neural crest organogenic control. Pregnant rats were exposed to either all-trans retinoic acid (125 mg/kg; n=17) or vehicle (n=10) on E10. Fetuses were recovered on E21 and external and internal malformations were sought. The craniofacial area, the trachea, parathyroids, thymus, thyroid, heart, great vessels, and adrenals were examined. In contrast with normal controls, 100% of retinoic acid animals had craniofacial, 94% anorectal, 90% limb, and 55% neural tube defects. The thymus was absent or ectopic in 76%, the parathyroids were absent or single in 88%, and the thyroid was abnormal in 41%. There were neural crest-type (outflow tract and/or pharyngeal aortic arch defects) cardiovascular malformations in 90% and the adrenals were absent in 52%. Interestingly, 9 of 11 (88%) animals with neural tube defects had absent adrenal glands. This association was significant (p<0.01) by Fisher exact test. Among the complex mechanisms of retinoic acid teratogenesis, severe disturbances of the neural crest pathway play a leading role. The simultaneous development of neural tube defects and adrenal agenesis suggests common pathogenic pathways.     

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.     

全反视黄酸对哮喘大鼠气道反应性和气道重塑的影响

目的：观察全反视黄酸(ATRA)对哮喘大鼠气道反应性、气道重塑和肺组织基质金属蛋白酶-9(MMP-9)表达的影响。方法：40只大鼠随机分为5组,每组8只：盐水组、模型组、ATRA组、棉籽油组和布地奈德（BUD）组。后4组经卵清蛋白（OVA）致敏14 d后激发6周,构建大鼠慢性哮喘模型。ATRA组、棉籽油组和BUD组每次激发前分别给予ATRA 50 μg/kg、棉籽油1 mL和BUD 0.32 mg/kg。5组大鼠行气道反应性检测,并测定肺组织MMP-9表达和气道重塑情况。结果：ATRA干预组的气道反应性与盐水组比较差异无统计学意义（P＞0.05）,MMP-9表达高于盐水组,差异具有统计学意义（P＜0.05）。ATRA干预组的气道反应性和MMP-9表达均明显低于模型组,气道重塑改变减轻,差异具有统计学意义（P＜0.05）。结论：早期预防性ATRA干预通过减少肺组织MMP-9表达,可在一定程度上减轻哮喘大鼠的气道重塑和气道高反应性。     

小剂量维甲酸诱导对神经母细胞瘤耐药的影响

目的探讨小剂量维甲酸诱导对神经母细胞瘤(NB)化疗耐药的影响。方法选择人NB细胞株SH SY5Y,用RT PCR方法检测小剂量全反式维甲酸(ATRA)作用下TrkB mRNA水平;通过四甲基偶氮蓝比色(MTT)法及流式细胞仪(FCM)检测ATRA诱导前后顺铂对人NB细胞株SH SY5Y的生长及凋亡的影响。结果SH SY5Y中未检测到TrkB mRNA表达,用1、10、100nM/LATRA诱导5d后可检测到TrkB mRNA表达,且随ATRA浓度增加TrkB mRNA水平逐渐升高。100nM/LATRA诱导7d,TrkB mRNA的相对比值与诱导5d比差异无显著性意义(P>0.05);MTT分析显示:BDNF+顺铂组(无TrkB表达)、ATRA+顺铂组(无BDNF刺激)细胞存活率同单用顺铂组比较无显著性差异(P>0.05);10nM/LATRA+BDNF+顺铂组NB细胞存活率明显高于单用顺铂组(P<0.01);FCM分析显示:ATRA+BDNF+顺铂组NB细胞凋亡率明显低于单用顺铂组(P<0.01)。结论存在BDNF的条件下,小剂量ATRA能阻断顺铂对SH SY5Y的细胞毒性作用,从而使SY5Y细胞对化疗耐药。     

维甲酸对大鼠高氧肺损伤的保护机制及其与调控丝裂原活化蛋白激酶的关系

目的 探讨维甲酸(RA)对高氧肺损伤保护作用机制及其与调控丝裂原活化蛋白激酶(MAPKs)关系.方法 建立高氧(85%)暴露早产SD大鼠肺损伤模型,运用RT-PCR方法检测基质金属蛋白酶2,9(MMP-2、-9)mRNA表达,采用明胶酶谱法检测MMP-2和MMP-9酶原及活酶表达,采用Western blot技术检测磷酸化和非磷酸化总的ERK1/2、JNK1/2和038蛋白质表达.结果 与空气组比较,高氧暴露4、7、14 d,MMP-2和MMP-9 mRNA的表达均显著提高(P均<0.01),MMP-2活酶(除4 d外)、MMP-9酶原及活酶的表达明显上调(P<0.05或P<0.01),磷酸化ERK1/2、JNK1/2和p38表达显著增加(P均<0.01);与高氧组比较,4、7、14 d时,RA明显下调高氧暴露后MMP-2(除14d外)、MMP.9 mRNA的表达(P<0.01或P<0.05),不同程度降低MMP-2活酶、MMP.9酶原及活酶的表达和显著下调磷酸化JNK1/2、038水平,进一步上调磷酸化ERK1/2表达.结论 高氧暴露显著提高MMP-2和MMP-9表达,是造成肺损伤的重要因素;JNK1/2和p38信号途径可能参与了高氧暴露下早产大鼠肺组织MMP-2和MMP-9的表达调控;RA可通过降低JNK1/2和p38磷酸化水平,抑制MMP-2和MMP-9的高表达和活化,从而发挥高氧肺损伤保护作用.     

高氧对早产鼠和足月鼠肺损伤的实验研究

目的探讨高氧对早产鼠和足月鼠肺损伤的影响。方法早产和足月新生鼠分别置于常压高氧舱中(＞95％O2)和正常空气中暴露7～14d,对比观察其生存率,肺组织病理学改变以及肺组织抗氧化酶(AOE)活性。结果与空气对照组比较,高氧组均发展为肺损伤,早产鼠的肺损伤较足月鼠严重,生存率较足月鼠低。高氧暴露下足月和早产鼠其肺组织超氧化物歧化酶(SOD)活性明显增加(P＜0.05),过氧化氢酶(CAT),谷胱甘肽过氧化酶(GP)也显示增加的趋势(P＞0.05)。结论早产鼠和足月鼠对高氧均有一定的耐受力,但早产鼠更易发生肺损伤。     

Effects of dietary choline and N,N-dimethylaminoethanol on lung phospholipid and surfactant of newborn rats.

Pups delivered by rats fed during pregnancy a choline-deficient (CD) diet containing 1% N,N-dimethylaminoethanol (DME) die within 36 hr of birth. The concentrations of sphingomyelins, phosphatidyl cholines, and disaturated phosphatidyl cholines in the lungs of these pups are lower than those in the lungs of pups delivered by dams fed a choline-supplemented diet (CS). The amount of surfactant isolated from the lung of the pups was also reduced. These changes were accompanied by alterations in the activity of enzymes (choline kinase, EC 2.7.1.32; choline phosphotransferase, EC 2.7.8.2) involved in the synthesis of lung lecithins. These results strongly suggest that pups delivered by dams fed a CD diet containg 1% DME die of respiratory distress syndrome due to altered metabolism of lung surfactant.     

吸入高浓度氧对大鼠肺泡发育过程促红细胞生成素受体的影响

目的 探讨大鼠肺泡发育阶段促红细胞生成素受体(erythropoietin receptor,EPOR)的动态变化以及吸入高浓度氧对EPOR的影响.方法 将48只新生Wistar大鼠生后12 h内随机分为空气组和高氧组.高氧组将动物置于自制密闭氧箱中,持续输入氧气,FiO2=0.85±0.02.在实验3,7和14 d每组随机选取8只处死,采集标本.采用HE染色观察肺组织病理改变,放射状肺泡计数评价肺泡化程度,免疫组织化学法检测肺组织血小板内皮细胞黏附分子-1(platelet endothelial cell adhesion molecule-1,PECAM-1)及EPOR表达,PT-PCR及Western blot法检测肺组织EPOR基因和蛋白表达.结果 高氧组3 d时肺毛细血管扩张、充血,7 d时肺泡体积增大、数量减少,14 d时肺泡数量及毛细血管进一步减少.空气组RAC值随日龄增长而增加,与空气组相比,高氧组7 d时RAC值降低[(6.85±104):(7.33±1.0),P＜0.01],差异在14 d更显著[(6.20±1.58):(9.07±0.69),P＜0.001].空气组PECAM-1表达随日龄增长逐渐增强,高氧组7 d和14 d PECAM-1表达较空气组明显减弱[(15.14±1.51):(31.47±2.43),(11.04±1.76):(41.41±3.83),P＜0.001].空气组EPOR染色在生后3 d最强,随日龄增长逐渐减弱,与空气组相比,高氧组各时点EPOR表达均明显减弱[(1.62±0.04):(1.82±0.06),P＜0.05;(0.48±0.01):(1.10±0.07),(0.39±0.04):(0.87±0.03),P＜0.001].空气组EPOR mRNA表达在生后3 d最强,高氧组各时点EPOR mRNA表达较空气组明显减弱[(0.87±0.07):(1.1±0.17),(0.18±0.07):(0.36±0.08),P＜0.01;(0.14±0.05):(0.36±0.09),P＜0.001].结论 EPOR可能在正常肺泡发育过程发挥调节作用,吸入高浓度氧导致的肺泡及血管发育阻滞可能与EPOR及PECAM-1蛋白表达减弱有关.

Abstract：

Objective Oxygen toxicity is thought to be a major contributing factor in the pathogenesis ofbronchopulmonary dysplasia (BPD). Animal experiments reveal that erythropoietin (EPO) may have protective effects against hyperoxic lung injury, but the mechanisms remain unknown.The aim of this study was to evaluate effects of hyperoxia on erythropoietin receptor expression in lung development of neonatal rats.Methods Several litters of Wistar pups were pooled together within 12 hours after birth and randomly divided into two groups (n = 24 in each ): air-exposed control group and hyperoxia-exposed group. In hyperoxia-exposed group, the rats were exposed to 85% oxygen. Pups ( n = 8 ) from each group were sacrificed on postnatal days 3, 7, and 14.The pulmonary histologcal and morphometric changes were observed after hematoxylin-eosin (HE) staining under light microscope. Radical alveolar counts ( RAC )were compared between the two groups to evaluate the differences of aveolarization. Expressions of platelet endothelial cell adhesion molecule-1 ( PECAM-1 ) and erythropoietin receptor (EPOR) in lung tissue were measured by immunohistochemistry.Expressions of EPOR mRNA and EPOR protein were measured by RTPCR and Western blotting. Results In hyperoxia-exposed group, there were a few inflammatory cells infiltration in interstitium on day 3 and inflammatory response worsened on day 7. Alveolar and capillary hypoplasia and interstitial fibrosis were evident on day 14.RAC increased in air-exposed control group along with the age in days. RAC decreased from day 7 in hyperoxia-exposed group compared with air-exposed control group [( 6.85 ± 1.04 ) vs.( 7.33 ± 1.0 ), P ＜ 0.01], which was more evident on day 14 [( 6.20 ±1.58 ) vs.(9.07 ± 0.69 ), P ＜ 0.001].Expression of PECAM-1 protein increased in air-exposed control group along with the age in days.But in hyperoxia-exposed group, it decreased on day 7 and 14 [( 15.14 ±1.51) vs.(31.47 ±2.43),(11.04 ± 1.76)vs.(41.41 ±3.83),P＜0.001]compared with air-exposed control group.Expression of EPOR on day 3 in air-exposed control group was the strongest and weakened gradually with the increase of postnatal days.Expression of EPOR in hyperoxia-exposed group decreased on day 3 and became more evident on day 7 and day 14 compared with air-exposed control group [( 1.62 ±0.04) vs.(1.82±0.06), P＜0.05;(0.48 ±0.01)vs.(1.10±0.07), (0.39±0.04) vs.(0.87±0.03 ) ,P ＜0.001].Expression of EPOR mRNA on day 3 in air-exposed control group was the strongest and was decreased significantly in hyperoxia-exposed group compared with air-exposed control group at all time points [(0.87±0.07)vs.(1.1±0.17),(0.18±0.07)vs.(0.36±0.08),P＜0.01;(0.14±0.05)vs.(0.36 ± 0.09 ), P ＜ 0.001]. Conclusions EPOR may participate in the modulation of normal lung development.Depressed expression of EPOR and PECAM-1 may be involved in the pathogenesis of alveolar and capillary hypoplasia induced by hyperoxia.