Animals ; Cecum/microbiology* ; Hyperoxia/blood* ; Microbiota ; Rats

OBJECTIVETo investigate the role of oxidative stress in the pathogenesis of retinal injury induced by hyperoxia.

METHODSSixty immature Sprague-Dawley (SD) rats born at a gestational age of 21 days, were randomly exposed to room air (air group, n=30) or 95% oxygen (hyperoxia group, n=30) immediately after birth. Plasma 8-iso-prostaglandin F2alpha (8-iso-PGF2alpha) levels were determined by ELISA. The ultrastructures of the retina were observed under a transmission electron microscope.

RESULTSThe plasma 8-iso-PGF2alpha contents of the air group were 19.09 +/-5.57, 18.24+/-5.91 and 17.00 +/- 5.58 pg/mL on the 3rd, 7th and 14th days after birth, respectively (F=1.024, P> 0.05). The plasma 8-iso-PGF2 contents in the hyperoxia group on the 3rd (28.33 +/- 5.59 pg/mL), the 7th day (51.20 +/- 15.01 pg/mL) and 14th day (84.54 +/- 14.85 pg/mL) after birth were significantly higher than those of the air group (t=2.863, P< 0.05; t=5.073, P< 0.01; t=11.006, P< 0.01). Moreover, the plasma 8-iso-PGF2 contents in the hyperoxia group increased with the prolonged hyperoxia exposure (F=150.7, P < 0.01). The ultrastructures of retina in the air group were normal. Hyperoxia exposure resulted in abnormalities of the ultrastructures of retina, manifesting as the membrane discs rarefied, twisted and disrupted and mitochondrial swelling.

CONCLUSIONSOxidative stress can results in retinal injury in immature rats. An increased plasma level of 8-iso-PGF2alpha is related to the injury degree of retina.

Animals ; Dinoprost ; analogs & derivatives ; blood ; Humans ; Hyperoxia ; complications ; metabolism ; pathology ; Infant, Newborn ; Lipid Peroxidation ; Oxidative Stress ; Rats ; Rats, Sprague-Dawley ; Retina ; metabolism ; pathology ; ultrastructure ; Retinopathy of Prematurity ; etiology

OBJECTIVETo study the effects of prolonged 85% oxygen exposure on lung vascular development and the expression of angiopoietin-1 (Ang-1) in the neonatal rat lungs.

METHODSNinety-six Sprague-Dawley rat pups were randomly exposed to air (control group) and 85% oxygen (experimental group) 6 hrs after birth. The rats were sacrificed 3, 7 and 14 days after exposure and their lungs were sampled. The lung sections were stained with hematoxylin and eosin for histological evaluation and analysis of vessel volume density. Expressions of angiopoietin-1 (Ang-1) in lung tissue were measured by immunohistochemistry. Expression of Ang-1 protein and mRNA was detected by Western Blot and Real time-PCR.

RESULTSAfter being exposed to 85% oxygen for 14 days, lung tissues had pathological changes as "new" bronchopulmonary dysplasia (BPD). The RAC on day 7 and day 14 in experimental group decreased significantly as compared with the control group [(10.55 ± 0.13) vs. (11.74 ± 0.19), (12.47 ± 0.05) vs. (15.03 ± 0.16), P < 0.05]. The X-ray showed that the diameter of lung vessel was much smaller and the vessels had less branches in experimental group compared with the control group on day 14. The vessel volume density on day 14 in experimental group decreased significantly as compared with the control group [(3.55 ± 0.09) vs. (6.03 ± 0.16), P < 0.05]. Immunohistochemistry and Western blotting showed that the expressions of Ang-1 protein on day 7 and day 14 in the experimental group decreased significantly as compared with the control group [(4.27 ± 0.34) vs. (3.10 ± 0.29), P < 0.05, (5.65 ± 0.49) vs. (3.21 ± 0.28), P < 0.01], [(0.88 ± 0.31) vs. (0.41 ± 0.12), P < 0.05, (0.90 ± 0.29) vs. (0.21 ± 0.06), P < 0.01]. The expressions of Ang-1 mRNA on day 7 and day 14 in the experimental group also decreased significantly as compared with the control group [(0.85 ± 0.14) vs. (0.44 ± 0.21), P < 0.05, (0.87 ± 0.24) vs. (0.24 ± 0.05), P < 0.01].

CONCLUSIONSProlonged exposure of high concentration of oxygen may cause impairment of lung vascular development by inhibiting expression of Ang-1 in neonatal rats, which is likely to contribute to pathogenesis of BPD.

Angiopoietin-1 ; metabolism ; Animals ; Animals, Newborn ; Hyperoxia ; Lung ; blood supply ; metabolism ; Pulmonary Artery ; growth & development ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Vascular Endothelial Growth Factor A ; metabolism

OBJECTIVETo explore the effect of resveratrol on the levels of sirtuin 1 (SIRT1) and reactive oxygen species (ROS) in peripheral blood mononuclear cells (PBMCs) of premature infants exposed to hyperoxia.

METHODSPeripheral blood and isolated PBMCs from premature infants (gestational age<32 weeks) without oxygen supplement were collected and were randomly assigned into four groups: control, air+resveratrol, hyperoxia, and hyperoxia+resveratrol. The PBMCs were cultured in vitro for 48 hours, then the ROS content in PBMCs was measured by laser scanning confocal microscopy. Malondialdehyde (MDA) content in the medium was measured by the whole spectrum spectrophotometer. SIRT1 positioning was assessed by immunofluorescence. SIRT1 expression levels in PBMCs were measured by Western bolt.

RESULTSCompared with the control group, the level of SIRT1 in the air+resveratrol group increased significantly (P<0.05). The levels of ROS and MDA and the SIRT1 transposition rate in the hyperoxia group increased significantly, while the expression level of SIRT1 decreased significantly compared with the control group (P<0.05). The levels of ROS and MDA and the SIRT1 transposition rate decreased significantly (P<0.05), and the expression level of SIRT1 increased significantly in the hyperoxia+resveratrol group (P<0.05).

CONCLUSIONSResveratrol can increase SIRT1 expression in PBMCs and inhibit SIRT1 shuttle from nucleus to cytoplasm in order to increase the ability of antioxidative stress in premature infants exposed to hyperoxia, thereby reducing the oxidative stress injury in premature infants.

Female ; Humans ; Hyperoxia ; metabolism ; Infant, Newborn ; Infant, Premature ; Leukocytes, Mononuclear ; metabolism ; Lipid Peroxidation ; Male ; Oxidative Stress ; Sirtuin 1 ; blood ; Stilbenes ; pharmacology

PURPOSE: To determine the effect of changing practice guidelines designed to avoid hyperoxia or hypoxia in very low birth weight or very preterm infants. METHODS: We analyzed a database of <1,500 g birth weight or <32 weeks of gestation infants who were born and admitted to the neonatal intensive care unit of Chungnam National University Hospital from January 2007 to July 2010. First, we defined the relationship between arterial partial pressure of oxygen (PaO2) and pulse oxygen saturation (SpO2). When we evaluated 96 pairs of PaO2 and SpO2 measurements, oxygen saturation was 90-94% at a PaO2 of 43-79 mmHg on the oxyhemoglobin dissociation curve, according to pulse oximetry. Based on this observation, a change in practice was instituted in August 2008 with the objective of avoiding hypoxia and hyperoxia in preterm infants with targeting a SpO2 90-94% (period II). Before the change in practice, high alarms for SpO2 were set at 100% and low alarms at 95% (period I). RESULTS: Sixty-eight infants the met enrollment criteria and 38 (56%) were born during period II, after the change in SpO2 targets. Demographic characteristics, except gender, were similar between the infants born in both periods. After correcting for the effect of confounding factors, the rates for mortality, severe retinopathy of prematurity, and IVH attended to be lower than those for infants in period II. No difference in the rate of patent ductus arteriosus needed to treat was observed. CONCLUSION: A change in the practice guidelines aimed at avoiding low oxygen saturation and hyperoxia did not increase neonatal complication rates and showed promising results, suggesting decreased mortality and improvements in short term morbidity. It is still unclear what range of oxygen saturation is appropriate for very preterm infants but the more careful saturation targeting guideline should be considered to prevent hypoxemic events and hyperoxia.
Anoxia ; Birth Weight ; Blood Gas Analysis ; Dissociative Disorders ; Ductus Arteriosus, Patent ; Humans ; Hyperoxia ; Infant ; Infant, Newborn ; Infant, Premature ; Infant, Very Low Birth Weight ; Intensive Care, Neonatal ; Oximetry ; Oxygen ; Oxyhemoglobins ; Partial Pressure ; Pregnancy ; Retinopathy of Prematurity

PURPOSE: This study was performed to evaluate the long-term effects and safety of intratracheal (IT) transplantation of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) in neonatal hyperoxic lung injury at postnatal day (P)70 in a rat model. MATERIALS AND METHODS: Newborn Sprague Dawley rat pups were subjected to 14 days of hyperoxia (90% oxygen) within 10 hours after birth and allowed to recover at room air until sacrificed at P70. In the transplantation groups, hUCB-MSCs (5x10(5)) were administered intratracheally at P5. At P70, various organs including the heart, lung, liver, and spleen were histologically examined, and the harvested lungs were assessed for morphometric analyses of alveolarization. ED-1, von Willebrand factor, and human-specific nuclear mitotic apparatus protein (NuMA) staining in the lungs and the hematologic profile of blood were evaluated. RESULTS: Impaired alveolar and vascular growth, which evidenced by an increased mean linear intercept and decreased amount of von Willebrand factor, respectively, and the hyperoxia-induced inflammatory responses, as evidenced by inflammatory foci and ED-1 positive alveolar macrophages, were attenuated in the P70 rat lungs by IT transplantation of hUCB-MSCs. Although rare, donor cells with human specific NuMA staining were persistently present in the P70 rat lungs. There were no gross or microscopic abnormal findings in the heart, liver, or spleen, related to the MSCs transplantation. CONCLUSION: The protective and beneficial effects of IT transplantation of hUCB-MSCs in neonatal hyperoxic lung injuries were sustained for a prolonged recovery period without any long-term adverse effects up to P70.
Animals ; *Cord Blood Stem Cell Transplantation ; Ectodysplasins/metabolism ; Humans ; Hyperoxia/*pathology ; Lung/metabolism/pathology ; Lung Injury/pathology/*surgery ; *Mesenchymal Stem Cell Transplantation ; Models, Animal ; Nuclear Matrix-Associated Proteins/metabolism ; Rats ; Trachea/*transplantation ; von Willebrand Factor/metabolism

OBJECTIVETo explore the expression of CASZ1 and its relationship with the pulmonary microvascular development in lung tissue of newborn rats exposed to hyperoxia which induced bronchopulmonary dysplasia (BPD).

METHODForty-eight newborn Sprague Dawley(SD) rats (male and female unlimited) were randomly divided into two groups: experimental group and control group according to random digits table with 24 in each.The rats in experimental group were exposed to high oxygen volume fraction of 800 ml/L and the rats in control group were exposed to normal air. Eight rats were randomly selected from each group on day 3 and 7 after oxygen exposure.The sections of lung were stained with HE method in order to assess lung histological changes, the alveolar development was evaluated by the number of radial alveolar count (RAC) and septal wall thickness. CD31 was detected by immunohistochemistry (IHC) method and the capillary density was calculated. The location, distribution and expression of CASZ1 in the lung tissue were detected by the immunohistochemistry, Western blotting, and quantitative PCR (qPCR).

RESULT(1) Stained by HE, lungs of experimental group showed destroyed alveoli, alveoli fusion and increased septal wall thickness, RAC were significantly lower than those in control group(14 d: septal wall thickness (12.69 ± 0.63) μm vs. (6.53 ± 0.16) μm, RAC 5.9 ± 0.4 vs. 8.4 ± 1.0, t = 19.046, 4.760, P both = 0.000). (2) CD31 protein was expressed predominantly in cytoplasm of pulmonary microvascular endothelial cells. The experimental group CD31 average optical density (AIOD) were decreased compared with control group((16.6 ± 1.6) × 10(3) vs.(40.1 ± 2.4) × 10(3), (18.1 ± 1.4) × 10(3) vs.(83.2 ± 5.2) × 10(3), (49.2 ± 5.4) × 10(3) vs.(136.2 ± 28.1) × 10(3), t=16.185, 16.066 and 6.078, P<0.01 for all comparisons). Capillary density in experimental group was also significantly decreased compared with control group ((3.84 ± 0.15)% vs.(6.01 ± 0.22)%, (4.17 ± 0.38)% vs.(6.15 ± 0.24)%, (5.43 ± 0.44)% vs. (9.13 ± 0.25)%, t = 16.124, 8.773 and 14.076, P all < 0.01). (3)RT-qPCR and Western blotting showed that the CASZ1 mRNA significantly increased in experimental group compared with control group(0.56 ± 0.17 vs. 1.00 ± 0.26, 0.32 ± 0.29 vs. 0.58 ± 0.14, 0.14 ± 0.22 vs. 0.56 ± 0.15, t=3.890, 3.303 and 2.388, P < 0.05 for all comparisons), and the protein expression of CASZ1 also significantly increased in experimental group compared with control group (0.65 ± 0.02 vs. 0.78 ± 0.23, 0.46 ± 0.03 vs. 0.75 ± 0.05, 0.34 ± 0.22 vs. 0.75 ± 0.04, t=6.200 and 10.485 and 14.998, P < 0.05 for all comparisons). (4)The protein level of CASZ1 in experimental group was positively correlated with capillary density (r=0.519, P<0.01).

CONCLUSIONCASZ1 is involved in the whole process of newborn rats BPD and may be linked to pulmonary microvascular dysplasia.

Animals ; Animals, Newborn ; Bronchopulmonary Dysplasia ; pathology ; Female ; Hyperoxia ; pathology ; Lung ; blood supply ; pathology ; Male ; Oxygen ; adverse effects ; Pulmonary Alveoli ; RNA, Messenger ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Transcription Factors ; metabolism