高氧诱导支气管肺发育不良新生小鼠肺组织中lncRNA表达谱的变化

目的:分析长链非编码RNA (long non-coding RNA,lncRNA)在高氧诱导支气管肺发育不良(bronchopulmonary dysplasi,BPD)小鼠模型肺中表达谱的变化?方法:构建高氧诱导支气管肺发育不良新生小鼠模型,利用lncRNA芯片技术检测正常小鼠肺及BPD小鼠肺组织中lncRNA表达谱的变化,经过对原始数据进行预处理,筛选出差异表达的lncRNA?结果:与对照组相比,模型组差异表达的lncRNA(差异倍数≥2倍且P < 0.05)共1 769条,其中882条上调,887条下调;5倍以上上调的共140条,下调的共71条;10倍以上上调的共28条,下调的有2条?结论:高氧诱导BPD发生时,肺组织中lncRNA的表达谱发生了显著变化;这些差异表达的lncRNA,可能参与了BPD发生?发展过程?     

Exogenous reactive oxygen and nitric oxide alter intracellular oxidant status of skeletal muscle fibres

To test whether exogenous oxidants alter intracellular oxidant levels in skeletal muscle fibres, we exposed rat diaphragm to donors of nitric oxide (NO_x), reactive oxygen species (ROS) or hyperoxia, and monitored intracellular oxidant levels using a fluorescent probe. Fibre bundles were dissected from the diaphragm and loaded with 2’,7’-dichlorodihydrofluorescein (DCFH); emissions were monitored using a fluorescence microscope. DCFH-loaded muscles were exposed to either a NO_x donor (1 m M S-nitroso-N-acetyl penicillamine, SNAP; 1 m M sodium nitroprusside, SNP; 400 μM 1-hydroxy-2-oxo-3-(N-3-methyl-aminopropyl)-3-methyl-1-triazen, NOC-7), an ROS donor (100 μM hydrogen peroxide, H₂O₂; 100 μM tert-butyl hydroperoxide; 1 m M hypoxanthine plus 0.01 U mL^–1 xanthine oxidase, HXXO) or a range of PO ₂s (25, 60 or 95% O₂ oxygenating Krebs–Ringer solution) for 40 min; time-matched control bundles remained in Krebs–Ringer solution. Control muscles oxidized DCFH at a rate of 0.32 ± 0.1 greyscale units min^–1. SNAP (766%), SNP (1244%), NOC-7 (851%), H₂O₂ (543%), and HXXO (541%) increased DCFH oxidation from control levels. The increase in emissions caused by NOC-7 and SNP were blunted by the NO_x scavenger haemoglobin (1 μM ). DCFH oxidation by HXXO was unaffected by 1000 U mL^–1 superoxide dismutase but was significantly decreased by 1000 U mL^–1 catalase and 1 m M salicylate. PO ₂ had no effect on intracellular oxidant levels. Therefore, extracellular NO_x and ROS can alter intracellular oxidant status in skeletal muscle fibres. These observations suggest that intrafibre oxidant levels could be the result of both intracellular and extracellular oxidant production.     

APE/Ref-1 responses to oxidative stress in aged rats

Chronic oxidative stress has been hypothesized to be a major contributor to the aging process. The continued exposure to reactive oxygen species (ROS) generated by oxidative metabolism or environmental sources can damage critical cellular structures and be responsible for some age-related pathology. The exposure of rodents to 100% oxygen, isobaric hyperoxia, increases ambient ROS levels and significantly increases apoptosis in brain. The deleterious effects of ROS also include increased lipid peroxidation, protein oxidation, and DNA damage. Although differences in the relative amounts of oxidative stress in young and old brains have been observed, the mechanisms responsible for impaired aging-associated DNA repair processes have not been characterized. We measured DNA levels of the DNA repair enzyme apurinic/apyrimidinic endonuclease (APE/Ref-1) protein by Western blot analysis in the brains of young (3-month) and old (30-month) male rats exposed to isobaric hyperoxia. Given that APE/Ref-1 is the rate-limiting enzyme in the repair pathway of apurinic/apyrimidinic sites generated in DNA by oxidative damage, we assumed that APE/Ref-1 protein levels were a good reflection of ongoing DNA base excision repair. Isobaric hyperoxia stimulated APE/Ref-1 expression in the hippocampus and basal forebrain of young rats experiencing 100% oxygen for 6 hr, while aged rats showed no significant changes in APE/Ref-1 protein levels in all brain areas at any time tested (0–48 hr) after hyperoxia. Differences in the stress-induced levels of expression of DNA repair enzymes may contribute to apoptotic increases and pathology associated with the aging process. J. Neurosci. Res. 54:635–638, 1998. © 1998 Wiley-Liss, Inc.     

常压高浓度氧对脑缺血-再灌注大鼠缺血核心区核转录因子-κB的适度调节作用

目的 探究常压高浓度氧治疗（normobaric hyperoxia,NBO）对脑缺血-再灌注大鼠脑内白细胞介素-1β（interleukin 1β,IL-1β）、肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）、核转录因子（nuclear factor-κB,NF-κB）及其抑制蛋白（inhibitor of κB,IκB）表达的影响,探讨NBO治疗对脑缺血后NF-κB介导的炎性反应损伤的作用。方法 将15只健康雄性SD大鼠（280~320 g）依据数字表法随机分为3组：假手术组（Sham,n=3）、正常氧浓度组（Normoxia,n=6）和NBO （n=6）组,应用线栓法制备大鼠大脑中动脉阻塞模型,缺血90 min再灌注24 h。Sham组和Normoxia组大鼠术后呼吸普通空气,NBO组大鼠术后至再灌注前呼吸100%常压氧气。采用免疫荧光染色和Western blotting的检测方法,研究NBO治疗对脑缺血核心区炎性因子IL-1β、TNF-α和转录调节因子NF-κB及其抑制蛋白IκB表达的影响。结果 免疫荧光结果显示：1与Sham组相比,Normoxia组缺血核心区IL-1β、TNF-α及核移位NF-κB p65阳性细胞数目明显增多（P<0.05）,荧光强度增强;2与Normoxia组相比,NBO组缺血核心区IL-1β、TNF-α及核移位NF-κB p65阳性细胞数目明显减少（P<0.05）,荧光强度减弱。Western blotting结果显示：1与Sham组相比,Normoxia组缺血核心区NF-κB p65显著升高,IκB明显降低（P<0.05）,2与Normoxia组相比,NBO组缺血核心区NF-κB p65水平显著降低,IκB明显升高（P<0.05）。结论 NBO治疗可能通过调节缺血核心区转录调控因子NF-κB的适度活化来抑制脑缺血再灌注炎性损伤,从而实现脑神经保护作用。     

Evidence for compromised data integrity in studies of liberal peri-operative inspired oxygen

In 2016 the World Health Organization recommended intra-operative ventilation with 80% inspired oxygen to reduce surgical site infection rates, based upon a meta-analysis of 15 randomised controlled trials, of which two were by Mario Schietroma's research group. Five trials by this group have been retracted for duplication, plagiarism, statistical error and lack of ethical approval. We analysed 40 papers by this group: 24 randomised controlled trials (5064 participants) and 16 observational studies (1847 patients). There was evidence that data integrity was compromised in 38 out of the 40 analysed papers. The distribution of baseline characteristics in randomised controlled trials was unlikely, p = 1.5 × 10⁻⁸: continuous variables within trials were heterogeneous, p = 1.9 × 10⁻⁹, and categorical variables were homogeneous, p = 8.5 × 10⁻²⁰. Effects of interventions varied less than expected between studies: for categorical variables, for instance postoperative wound infection, p < 1 × 10⁻⁷, and for continuous variables, for instance HLA-DR concentration, p = 0.00001. Of 184 calculable p values, for baseline variables or results, 179 (98%) were incorrect, ranging from three orders of magnitude too small to 10 orders of magnitude too large. Twenty-one graphs occurred 81 times in 23 out of 40 papers. Liberal peri-operative oxygen did not reduce surgical site infection in a meta-analysis of 20 trials that excluded seven trials by Mario Schietroma and colleagues (odds ratio (95%CI) 0.89 (0.73-1.08); p = 0.23). An update by the World Health Organization has now excluded trials of liberal oxygen by Schietroma's group, four of which have not been retracted. We conclude that Mario Schietroma's work should not inform practice until investigated.     

Can Oxygen Tension Contribute to an Abnormal Placental Cytokine Milieu?

OBJECTIVE The aim of this study was to determine whether culturing human placental explants under different oxygen tensions will alter expression of pro- and anti-inflammatory mediators. METHODS Placental explant cultures from second-trimester, elective, terminations-of-pregnancy were incubated under 21, 5, or 1% O(2) concentrations for 24 hr in the presence or absence of IL-10. Cytokine concentrations in the conditioned medium were quantified by immunoassay. RESULTS Culture of placental explants under 21, 5, or 1% O(2) concentrations produced hyperoxic (143 ± 1.6 mmHg), normoxic (37 ± 1.6 mmHg), and hypoxic (18.2 ± 1.6 mmHg) pO(2) levels for the maternal-fetal interface in the medium. Oxygen tension had profound effects on basal placental cytokine levels as well as on IL-10-stimulated cytokine production. IL-1β and TNF-α, but not IFN-γ production, was reduced by 21% O(2) . Moreover, 21% O(2) levels increased the anti-inflammatory cytokines IL-10 and IL-13 while 1% O(2) tended to decrease the production of these cytokines. CONCLUSIONS Five percent- O(2) incubation more accurately represents in vivo pO(2) conditions at the maternal-fetal interface. Routine culture of placental explants in room air produces a superphysiologic oxygen tension that tended to increase the production of anti-inflammatory and decrease the production of pro-inflammatory cytokines. In addition, low pO(2) may reduce responsiveness of the placenta to the anti-inflammatory actions of IL-10.     

Detection of 100% oxygen induced changes in retina using magnetic resonance imaging: a human study

Background Inner retinal oxygenation response （△PO2） is a worldwide study focus. However, the relevant reports on its radiological measurments are limited. In this study, magnetic resonance imaging （MRI）, employing T1 weighted image （T1WI）, was used to detect changes in APO2 following 100% oxygen inhalation in human subjects. Methods MRI was performed on a 1.5-T GE scanner system. After obtaining ophthalmologic data, eleven healthy individuals were given room air and 100% oxygen inhalation in order with different intervals. The MRI TlWl data were collected for 50 minutes. Data were analyzed with NIH IMAGE software. Results APO2 was not panretinally uniform, and changes in oxygenation response were spatially inhomogeneous. During the initial phase （before 5 minutes） of 100% oxygen inhalation, preretinal vitreous water signals in the region of papilla optica increased rapidly. On the contrary, in other regions signals declined. In a later period （35 minutes）, APO2 was panretinally fluctuated and increased slowly and attained homeostasis. After hyperoxia （45 minutes）, delayed-enhancement of preretinal vitreous water signals in regions other than the papilla optica occurred, and then dropped down. There was no significant difference （P 〉0.05） at any consecutive time point during and after hyperoixa. Conclusions These results reveal that hyperoxia can induce region-specific signal changes in preretinal vitreous water. Regulatory activity of the retinal vessel network may be the mechanism during 100% oxygen inhalation. Moreover, MRI is a valuable tool for investigating APO2 and exploring the mechanism of retinal oxygenation response physiologically or pathologically in vivo.