Animals ; Bronchopulmonary Dysplasia ; etiology ; Fibroblasts ; physiology ; Humans ; Hyperoxia ; pathology ; Infant, Newborn ; Lung ; embryology ; pathology

OBJECTIVEThis study aimed to explore the effects of hyperoxia on the development of fetal lung by investigating the changes of morphological and cell proliferation induced by hyperoxia in cultured fetal lungs as well as the effects of dexamethasone on hyperoxia-exposed lungs.

METHODSHuman fetal lung explants at the pseudoglandular stage of development were cultured randomly either in normoxia (21% O2/5% CO2) or hyperoxia (95% O2/5% CO2) for 72 hrs. Dexamethasone was added into the feeding medium at the concentration of 10(-6)M. Harvested tissues were stained for pancytokeratin to identify epithelial cells, with Ki-67 as a marker of proliferation. The effects of lung morphometry were analyzed using computer assisted image analysis. The mean airway thickness, the proportion of the surface area occupied by airways, the mean airway surface area and the index of the epithelium proliferation were measured.

RESULTSThe lung architectures remained unchanged after 72 hrs normoxia culture, whereas hyperoxia culture resulted in significant dilation of airways and thinning of epithelium, with the surface area of airways of 6662 microm(2) vs 2728 microm(2) and the thickness of airways of 7.8 microm vs 8.1 microm (P < 0.05). Hyperoxia culture also resulted in an increase in the proportion of the surface area occupied by airways than normoxia culture (35.2% vs 23.4%; P < 0.05). The surface area of airways (3174 microm(2)) and the proportion of the surface area occupied by airways (23.9%) decreased significantly in hyperoxia-cultured lungs after dexamethasone administration (P < 0.05). The epithelium proliferation index in hyperoxia-cultured lungs (21.8%) was higher than that in normoxia-cultured lungs (5.1%) and dexamethasone-treated hyperoxia-cultured lungs (7.4%) (P < 0.05).

CONCLUSIONSThe exposure of pseudoglandular lungs to hyperoxia modulates the lung architecture to resemble saccular lungs with higher epithelium proliferation index. Dexamethasone may inhibit the effects induced by hyperoxia.

Cell Differentiation ; drug effects ; Dexamethasone ; pharmacology ; Female ; Humans ; Hyperoxia ; pathology ; Lung ; drug effects ; embryology ; pathology ; Pregnancy

Animals ; Animals, Newborn ; Hyperoxia ; physiopathology ; Lung ; drug effects ; pathology ; Oxygen ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Tretinoin ; pharmacology ; therapeutic use

OBJECTIVE: To determine the dynamic expression of E2F1 in lung of premature rats with hyperoxia-induced chronic lung disease and the relation between E2F1 and pulmonary fibrosis. METHODS: Premature Wistar rats at 21 days gestation were randomly and equally divided into a hyperoxia group and a room air group. The hyperoxia group was continuously exposed to hyperoxia (90%) while the air group in room air. Lung tissues in the 2 groups were obtained at 3, 7 and 14 days after exposing to either room air or hyperoxia. The changes of pulmonary histopathology at different time points were observed by hematoxylin and eosin staining; the severity of pulmonary fibrosis was evaluated; and the expression of E2F1 in lung tissue was detected by immunohistochemistry and Western blot. RESULTS: After 3 days of hyperoxia, no significant interstitial fibrosis was observed; while after 7 days in the hyperoxia group, interstitial fibrosis was observed. These changes became more obvious after 14 days of prolonged hyperoxia exposure. No significant difference in the expressions of E2F1 protein was found between the hyperoxia group and the room air group 3 days postnatally (P>0.05). The expression of E2F1 in the hyperoxia group significantly increased 7 days and 14 days postnatally (P<0.05, P<0.01). CONCLUSION Abnormality of E2F1 expression is involved in the pathological process of the proliferation of lung fibroblasts in hyperoxia-induced chronic lung disease neonatal rats, and it plays an important role in lung fibrosis.
Animals ; Animals, Newborn ; E2F1 Transcription Factor ; metabolism ; Hyperoxia ; metabolism ; pathology ; Immunohistochemistry ; Lung ; pathology ; Lung Diseases ; metabolism ; pathology ; Pulmonary Fibrosis ; Rats ; Rats, Sprague-Dawley ; Rats, Wistar

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

OBJECTIVEResolution of alveolar damage after lung injury requires finely orchestrated processes that include coordinated and effective tissue reconstruction to reestablish a functional barrier. Reconstitution of denuded type I alveolar epithelial cell that undergo apoptotic and necrotic death after lung injury is required in many pulmonary diseases. Disruption of distal airway development and type II-type I alveolar epithelial cell differentiation after lung injury and disordered repair of the alveolus after injury is one of the predominant pathological characteristics of chronic lung disease (CLD) of premature infants. HoxB5 belongs to the Hox gene family encoding transcription factors known for their role in skeletal patterning and the elaboration of organs. HoxB5 is required for embryonic respiratory tract morphogenesis. The present study aimed to test the hypothesis that HoxB5 may participate in the etiology of CLD and to understand possible mechanism.

METHODSPremature rat pups were taken out surgically at gestational age 21 d. CLD was induced by hyperoxia exposure in neonatal premature rats. Eighty premature rats were randomly exposed to hyperoxia (FiO2 = 0.90, CLD group) and to room air (FiO2 = 0.21, control group) (n = 40 each). Lung specimens were obtained respectively on days 1, 3, 7, 14 and 21 after exposure. Histopathologic changes was assayed after hematoxylin and eosin (HE) staining and pulmonary development was evaluated by lung coefficient and radical alveolar counts (RAC), dynamic changes of RAC were observed; and the expression of HoxB5, AQP-5, and SP-B mRNA were assayed by reverse transcription polymerase chain reaction (RT-PCR).

RESULTSThere were no significant differences in the RAC and the expression level of HoxB5, AQP-5, and SP-B mRNA between the CLD and the control groups within 3 days after birth (P > 0.05). However, compared to the control group, the RAC of the CLD group was reduced (6.35 +/- 0.83 vs. 7.67 +/- 0.52), and the expression of HoxB5 (0.98 +/- 0.14 vs. 1.20 +/- 0.16), AQP-5 (0.78 +/- 0.11 vs. 1.04 +/- 0.19) mRNA were significantly lower (P < 0.05), while the expression of SP-B mRNA was increased on the 7th day (P < 0.05). On the 14th day, the RAC and the expression of HoxB5, AQP-5 mRNA of CLD group were significantly lower than those of the control group (P < 0.05), and the expression of SP-B mRNA continued to increase (P < 0.05). On the 21st day, the expression of HoxB5, AQP-5 mRNA decreased to the nadir (0.64 +/- 0.11 vs. 1.18 +/- 0.13 and 0.67 +/- 0.12 vs. 0.97 +/- 0.01, respectively) (P < 0.01), on the same day the expression of SP-B mRNA reached to the pinnacle (1.43 +/- 0.07 vs. 1.12 +/- 0.09) (P < 0.01). The expression of HoxB5 mRNA was positively correlated with RAC in the CLD group (r = 0.685, P < 0.01).

CONCLUSIONSWith hyperoxia exposure, the mRNA expression of specific marker of type I alveolar epithelial cell, AQP-5, was decreased while specific marker of type II alveolar epithelial cell, SP-B, was increased; and the expression of HoxB5 mRNA in lung tissues kept on decreasing. Decreased expression of HoxB5 may associate with the disruption of type II-I alveolar epithelial cell differentiation and thus may play an important role in inhibition of lung development with CLD. The altered Hox gene expression may predispose lung pathology.

Animals ; Animals, Newborn ; Female ; Homeodomain Proteins ; genetics ; metabolism ; Hyperoxia ; complications ; Lung ; growth & development ; metabolism ; pathology ; Lung Diseases ; etiology ; metabolism ; pathology ; Pregnancy ; RNA, Messenger ; metabolism ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo explore the effect of low-concentration lipopolysaccharide (LPS) pretreatment on hyperoxia-induced immature brain injury in neonatal mice and explore and the related mechanisms.

METHODSForty-eight neonatal mice on postnatal day 3 (PND3) were randomized into normal control group, LPS (0.3 mg/kg) group, hyperoxia group (hyperoxia exposure for 24 h), and hyperoxia+LPS group (hyperoxia exposure for 24 h 30 min after 0.3 mg/kg LPS treatment). At PND5, all the neonatal mice were sacrificed to examine the morphological changes of microglia in the periventricular white matter using Tomato lectin staining, measure malondialdehyde (MDA) content in the immature brain, detect mRNA expression of tumor necrosis factor-α (TNF-α) using real-time PCR, and determine caspase-3 protein expression with Western blotting.

RESULTSCompared with the control group, exposures to LPS, hyperoxia, and both all resulted in microglia activation in the periventricular white matter. The number of activated microglia, MDA content, TNF-α mRNA expression and caspase-3 protein expression in the immature brain were significantly higher in hyperoxia group than in the control group and LPS group (P<0.05). LPS pretreatment significantly enhanced hyperoxia-induced microglia activation in the immature brain (P<0.05).

CONCLUSIONHyperoxia causes immature brain injury mediated by microglia activation, and LPS pretreatment can enhance such brain injury in neonatal mice.

Animals ; Animals, Newborn ; Brain ; metabolism ; pathology ; Caspase 3 ; metabolism ; Hyperoxia ; Lipopolysaccharides ; adverse effects ; Malondialdehyde ; metabolism ; Mice ; Mice, Inbred C57BL ; Microglia ; metabolism ; pathology ; Tumor Necrosis Factor-alpha ; metabolism

OBJECTIVETo study the protective effect of hyperoxia solution on acute lung injury caused by phosgene poisoning by observing the changes of PaO2 and malondialdehyde (MDA) contents, superoxide dismutase (SOD) activity in serum and Glutathione (GSH/GSSG) contents in lung tissues.

METHODSThe rabbits were divided into normal control group, hyperoxia solution (H0) and balance salt (BS) groups. Group HO and Group BS inhaled phosgene and the former was given intravenously hyperoxia solution (which was replaced by balance salt solution in Group BS). The content of MDA and the activity of SOD in serum were observed at different time points, the amount of GSH and GSSG in lung tissue were also measured.

RESULTS(1) The serum MDA contents increased and PaO2, SOD activity decreased significantly in Group HO and Group BS along with time increasing as compared with control group. The contents of GSH in lung tissue decreased in two groups compared with that in control group, however the contents of GSSG ascended instead. (2) At 3 and 8 h of the experiment, PaO2 of Group HO [(9.91 +/- 0.49), (9.15 +/- 0.46) mm Hg respectively] were significantly higher than those of Group BS [(9.03 +/- 0.76), (8.11 +/- 0.57) mm Hg respectively] (P < 0.01). The contents of MDA of Group HO (3.66 +/- 0.35), (5.31 +/- 0.15) micromol/L respectively] were lower than those of Group BS [(4.32 +/- 0.26), (7.4 +/- 0.33) micromol/L respectively] (P < 0.01). SOD activity in Group HO [(237.37 +/- 29.96), (208.10 +/- 18.80) NU/ml respectively] were higher than those of Group BS [(195.02 +/- 21.44), (144.87 +/- 21.26) NU/ml respectively] (P < 0.05 or P < 0.01). The content of GSSG lung tissue in Group HO (423.67 +/- 38.21) micromol/L were lower than those of Group BS (523.85 +/- 43.14) mol/L (P < 0.01). There were no significant differences in the content of GSH in lung tissues between Group HO and group BS.

CONCLUSIONHyperoxia solution can reduce acute lung injury of rabbits following phosgene poisoning.

Acute Lung Injury ; etiology ; metabolism ; pathology ; Animals ; Glutathione Peroxidase ; metabolism ; Hyperoxia ; Lung ; drug effects ; metabolism ; pathology ; Malondialdehyde ; analysis ; Oxygen ; administration & dosage ; pharmacology ; Phosgene ; poisoning ; Rabbits ; Superoxide Dismutase ; metabolism

OBJECTIVETo study the effect of captopril on the histopathology and bronchoalveolar lavage fluid (BALF) in neonatal rats exposed to hyperoxia.

METHODSForty term neonatal Wistar rats were randomly assigned into Air control, Model, Normal saline control and Captopril-treated groups (n=10 each). The Air control group was exposed to air (FiO2=0.21). The remaining three groups were continuously exposed to hyperoxia (FiO2=0.90) . During exposure the Captopril-treated group received intragastric captopril (60 mg/kg daily) and the Normal saline control group was administered with normal saline. The Model group had no treatment. At the 14th and 21st days of exposure, the subjects were sacrificed. The lung coefficient and the protein contents and inflammatory cells in BALF were determined. The changes of lung histomorphology were observed.

RESULTSThe lung coefficient and the protein contents, the total number of cells and the percentage of neutrophils, lymphocytes and eosinophils in BAFL increased significantly in the Model and Normal saline control groups on the 14th and 21st days of exposure compared with those of the Air control group. Captopril treatment significantly reduced the lung coefficient and the protein contents, the total number of cells and the percentage of neutrophils and eosinophils in BALF. On the 14th day the lung coefficient decreased from 9.72 +/- 0.67 mg/g to 8.63 +/- 0.35 mg/g (P < 0.05); the protein contents in BALF from 0.619 +/- 0.023 g/L to 0.486 +/- 0.027 g/L (P < 0.05); and the total number of cells in BALF from (80.57 +/- 9.28)x10(4)/mL to (48.62 +/- 1.53)x10(4)/mL (P < 0.01) compared with the Model group. On the 21st day the lung coefficient decreased from 10.67 +/- 0.87 mg/g to 8.76 +/- 0.89 mg/g (P < 0.05); the protein contents in BALF from 0.978 +/- 0.012 g/L to 0.759 +/- 0.042 g/L (P < 0.05); and the total number of cells in BALF from (92.86 +/- 10.32) x10(4)/mL to (35.52 +/- 3.89) x10(4)/mL (P < 0.05) compared with the Model group. There were however significant differences in these results between the Captopril-treated and Air control groups. The histopathological examination demonstrated different degrees of alveolitis, broaden interstitium and reduced alveolar quantity in the Model and Normal saline control groups. The pathological changes were markedly alleviated after captopril treatment.

CONCLUSIONCaptopril may have protective effects on lung injury induced by hyperoxia.

Animals ; Animals, Newborn ; Bronchoalveolar Lavage Fluid ; chemistry ; cytology ; Captopril ; pharmacology ; Female ; Hyperoxia ; pathology ; Lung ; drug effects ; pathology ; Male ; Proteins ; analysis ; Rats ; Rats, Wistar

OBJECTIVETo explore the protective effects of mitochondrial ATP-sensitive potassium channel opener diazoxide on hyperoxia-induced apoptosis of type II alveolar epithelial cells (A549 cells) and possible mechanisms.

METHODSA549 cells were cultured in vitro and divided randomly into control, hyperoxia and diazoxide group. The hyperoxia group was exposed to a mixture of O2 (900 mL/L) and CO2 (50 mL/L) for 10 minutes, then cultured in a closed environment. The diazoxide group was pretreated with diazoxide of 100 μmol/L for 24 hrs before hyperxia induction. The cells were collected 12, 24 and 48 hrs after culture. The morphologic changes of A549 cells were observed under an inverted microscope. A549 cell apoptosis was detected by flow cytometry. The expression of Omi/HtrA2 in the endochylema of A549 cells was determined by immunohistochemistry.

RESULTSA549 cells were damaged and the changes in morphology of the cells were serious in the hyperoxia group. The apoptosis rate of A549 cells and the expression of Omi/HtrA2 in the endochylema increased in the hyperoxia group compared with the control group (P<0.05). The growth and the morphology of A549 cells were greatly improved and the cell injuries were obviously alleviated in the diazoxide group. The expression of Omi/HtrA2 in the endochylema and the apoptosis rate of A549 cells were significantly reduced in the diazoxide group compared with the hyperoxia group (P<0.05).

CONCLUSIONSDiazoxide as an opener of mitoKATP channel can reduce the expression of Omi/HtrA2 and the apoptosis rate of A549 cells, thus relieves the injury of A549 cells induced by hyperoxia.

Apoptosis ; Cells, Cultured ; Cytoprotection ; Diazoxide ; pharmacology ; High-Temperature Requirement A Serine Peptidase 2 ; Humans ; Hyperoxia ; complications ; Lung ; pathology ; Mitochondrial Proteins ; analysis ; Potassium Channels ; physiology ; Serine Endopeptidases ; analysis