The effect of nuclear factor erythroid 2 related factor 2-induced inhibition of ferroptosis on hyperoxia lung injury / 中华实用儿科临床杂志

Objective:To observe the expression changes of nuclear factor erythroid 2 related factor 2 (Nrf2) and glutathione peroxidase (GPX4) in human pulmonary microvascular endothelial cells (HPMEC) under different experimental conditions, and to explore the role of Nrf2 in inhibiting ferroptosis in the process of alleviating hyperoxic lung injury(HLI).Methods:Hyperoxic model was established by hyperoxia exposure.HPMEC were treated with blank control (control group), oxygen exposure at the concentration of 950 mL/L (hyperoxia group), oxygen exposure at the concentration of 950 mL/L+ 10 μmol/L Ferrostatin (ferroptosis inhibitor group) and oxygen exposure at the concentration of 950 mL/L + 10 μmol/L ML385 (Nrf2 inhibitor group). Cell viability at 24 h and 48 h was tested by the Cell Counting Kit-8 assay, and reactive oxygen species (ROS) levels were detected by a commercial ROS kit.The mRNA and protein levels of Nrf2 and GPX4 were detected by real-time quantitative polymerase chain reaction and Western blot, respectively.Differences were analyzed using the Student′s t-test for a two-group comparison or one-way ANOVA test among groups. Results:(1)Compared with the control group, significantly decreased viability and increased ROS levels were detected in hyperoxia group.Meanwhile, the mRNA (24 h: 0.750±0.010 vs.1.010±0.160, 48 h: 0.690±0.050 vs.1.000±0.070) and protein levels of GPX4 (24 h: 0.160±0.010 vs.0.290±0.010, 48 h: 0.190±0.010 vs.0.250±0.010) at 24 h and 48 h were significantly downregulated, while the mRNA (24 h: 1.740±0.050 vs.1.000±0.050, 48 h: 2.130±0.020 vs.1.000±0.030) and protein levels of Nrf2 (24 h: 0.840±0.010 vs.0.480±0.010, 48 h: 0.840±0.010 vs.0.550±0.030) at 24 h and 48 h were significantly upregulated in hyperoxia group than those of control group (all P<0.05). (2)Compared with the hyperoxia group, significantly increased viability and decreased ROS levels were detected in ferroptosis inhibitor group.Meanwhile, the mRNA (24 h: 1.520±0.110, 48 h: 1.880±0.050) and protein levels of GPX4 (24 h: 0.290±0.010, 48 h: 0.250±0.004) at 24 h and 48 h were significantly upregulated, while the mRNA (24 h: 0.780±0.040, 48 h: 0.760±0.030) and protein levels of Nrf2 (24 h: 0.480±0.010, 48 h: 0.540±0.020) at 24 h and 48 h were significantly downregulated in ferroptosis inhibitor group than those of hyperoxia group (all P<0.05). (3)Compared with the hyperoxia group, significantly decreased viability and increased ROS levels were detected in Nrf2 inhibitor group.Meanwhile, the mRNA (24 h: 0.600±0.030, 48 h: 0.590±0.003) and protein levels of GPX4 (24 h: 0.150±0.001, 48 h: 0.180±0.001) at 24 h and 48 h were significantly downregulated, while the mRNA level of Nrf2 was significantly upregulated at 24 h (3.360±0.130), but downregulated at 48 h (1.430±0.130) (all P<0.05). No significant difference was detected in the protein level of Nrf2 at 24 h and 48 h between hyperoxia group and Nrf2 inhibitor group ( P>0.05). Conclusions:Ferroptosis is involved in the development of HLI, and Nrf2 is able to alleviate hyperoxic lung injury by inhibiting ferroptosis.Therefore, inhibition of ferroptosis by Nrf2 may provide a new therapeutic target for HLI.

The role of hyperoxia-induced cellular senescence in bronchopulmonary dysplasia / 国际儿科学杂志

Bronchopulmonary dysplasia(BPD)is a chronic respiratory system disease that causes respiratory failure and death in premature infants, and hyperoxic exposure is the main risk factor for its occurrence.Cellular senescence describes a state of cell cycle blockade, and in recent years studies have confirmed that exposure to hyperoxia can cause cellular senescence.Cellular senescence plays a crucial role in the development of the lung epithelium, lung interstitium, pulmonary vasculature, and airways, and abnormal development of these tissues is associated with the development of BPD.Therefore, this paper takes cellular senescence and BPD as the starting point to review the mechanism of hyperoxia-induced cellular senescence in the occurrence and development of BPD and the anti-aging drugs currently applied in clinical practice, in order to provide a new direction for the prevention and treatment of BPD.

MicroRNA21-5p alleviates hyperoxia-induced acute lung injury in rats through activating phosphatidylinositol 3 kinase/serine-threonine protein kinase signaling pathway by regulating type Ⅱ alveolar epithelial cell apoptosis / 中华危重病急救医学

Objective:To investigate whether microRNA-21-5p (miR-21-5p) alleviates hyperoxia-induced acute lung injury (HALI) through activating the phosphatidylinositol 3 kinase/serine-threonine protein kinase (PI3K/Akt) signaling pathway by regulating apoptosis of type Ⅱ alveolar epithelial cell (AECⅡ).Methods:Seventy-two male Sprague-Dawley (SD) rats were divided into normozone-controlled group, HALI group, PI3K/Akt signaling pathway inhibitor LY294002+HALI group (LY+HALI group), miR-21-5p overexpression+LY294002+HALI group (miR-21-5p+LY+HALI group), miR-21-5p overexpression+HALI group (miR-21-5p+HALI group), and dimethyl sulfoxide (DMSO)+HALI group by random number table method with 12 rats in each group. Animal models of HALI were prepared using 95% concentrations of oxygen. The animals in the normozone-controlled group were fed normally under normoxia. Transfection of lung tissue by miR-21-5p adeno-associated viral vector AAV6-miR-21-5p was performed by instillation of 200 μL titer (1×10 12 TU/mL) through a tracheal catheter 3 weeks prior to modeling. DMSO and LY294002 were administered via the tail vein at 0.3 mg/kg 1 hour before modeling. After 48 hours of modeling, carotid artery blood was collected to detect oxygenation index (OI) and respiratory index (RI), and real-time fluorescence quantitative reverse transcription-polymerase chain reaction (RT-PCR) was used to detect miR-21-5p expression. Lung tissue was collected, and the levels of inflammatory factors including tumor necrosis factor-α (TNF-α) and interleukins (IL-6, IL-1β) were measured by enzyme-linked immunosorbent assay (ELISA), and the ratio of pulmonary wet/dry weight (W/D) was determined, and the pathological changes of lung histopathology were observed under the light microscopy after hematoxylin-eosin (HE) staining. Each group was purified AECⅡ cells from 6 rats, the apoptosis rate was detected by flow cytometry, and the expression levels of phosphatase and tensin homologous gene (PTEN), and proteins from the PI3K/Akt signaling pathway were detected by Western blotting. Results:Compared with the normozone-controlled group, alveolar septal thickening and massive inflammatory cell infiltration were found after hyperoxia exposure, RI, inflammatory factors, lung W/D ratio, pathological score, AECⅡ cells early apoptosis rate, PTEN protein expression and phosphorylation level of Akt were increased, while OI and miR-21-5p expression were decreased, indicating the successful preparation of the model. After pretreatment, LY294002 could aggravate the pathological injury of lung tissue in HALI rats, RI, inflammatory factors and lung W/D ratio were further increased, and OI was further reduced compared with HALI group. At the same time, it could promote the AECⅡ cell apoptosis, further up-regulate the expression of PTEN, and reduce the phosphorylation of Akt. However, miR-21-5p pretreatment could negatively regulate PTEN, activate PI3K/Akt signal pathway, inhibit AECⅡ cell apoptosis, and reduce HALI, which was shown by the decreased level of inflammatory factors in miR-21-5p+LY+HALI group compared with LY+HALI group [TNF-α (μg/L): 100.33±3.48 vs. 116.55±2.53, IL-6 (ng/L): 141.06±3.70 vs. 161.31±3.59, IL-1β (μg/L): 90.82±3.69 vs. 112.23±2.87, all P < 0.05], RI, lung injury pathology score, lung W/D ratio, and AECⅡ cell early apoptosis rate were significantly decreased [RI: 0.81±0.02 vs. 1.05±0.07, pathology score: 0.304±0.008 vs. 0.359±0.007, lung W/D ratio: 5.29±0.03 vs. 5.52±0.08, apoptosis rate: (27.20±2.34)% vs. (34.17±1.49)%, all P < 0.05], OI and expressions of miR-21-5p were significantly increased [OI (mmHg, 1 mmHg≈0.133 kPa): 266.71±2.75 vs. 230.12±4.04, miR-21-5p (2 -ΔΔCt): 2.21±0.13 vs. 0.33±0.03, both P < 0.05], and PTEN protein expression in AECⅡ cell was significantly reduced (PTEN/GAPDH: 0.50±0.06 vs. 0.93±0.06, P < 0.05), and phosphorylation level of Akt was significantly increased [phosphorylated Akt (p-Akt) protein (p-Akt/GAPDH): 0.86±0.05 vs. 0.56±0.06, P < 0.05]. Conclusion:miR-21-5p attenuates HALI by inhibiting AECⅡ cell apoptosis, possibly through negative regulation of PTEN to activate PI3K/Akt signaling pathway.

Role and mechanism of signal transducer and activator of transcription protein STAT1/3/5 in hyperoxia-induced acute lung injury / 中华危重病急救医学

Objective:To investigate whether signal transducer and activator of transcription (STAT1/3/5) have a protective effect on hyperoxia-induced acute lung injury (HALI) and its mechanism.Methods:Seventy C57BL/6J mice were randomly divided into five groups: normoxia control group, HALI group, and STAT1/3/5 inhibitor groups, with 14 mice in each group. The HALI model was established by exposure to more than 90% hyperoxia for 48 hours; three STAT inhibitor groups were pretreated by intraperitoneal injection of STAT1 inhibitor 40 mg/kg and STAT3 inhibitor 5 mg/kg, and STAT5 inhibitor 10 mg/kg for 1 week. Six blood samples were randomly collected from each group, and microRNA-21 (miR-21) expression was measured by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). Lung tissue of the sacrificed mice was obtained, and enzyme linked immunosorbent assay (ELISA) was used to detect the contents of tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1β), superoxide dismutase (SOD), malonic dialdehyde (MDA), and matrix metalloproteinase 9 (MMP9). The water content of lung tissue was calculated. The pathological changes in lung tissue were observed under the light microscope, and the pathological score of lung injury was performed. Western blotting was used to detect the expression of phosphorylated STAT (p-STAT1, p-STAT3, p-STAT5) in lung tissue. The 7-day cumulative survival rates of the remaining 8 mice in each group were analyzed using Kaplan-Meier survival curves.Results:Under the light microscope, the alveolar structures in the HALI group and the STAT1 inhibitor group were destroyed, a large number of neutrophils (NEU) infiltrated in the alveoli and lung interstitium, which were thickened. The pathological score of lung injury and the water content of the lung tissue was significantly increased. In STAT3 inhibitor and STAT5 inhibitor groups, the alveolar cavity was clear, the degree of NEU infiltration and the thickness of lung interstitium were lower than those in HALI group, the pathological score of lung injury and the water content of lung tissue were significantly decreased, especially in STAT3 inhibitor group. Compared with the normoxia control group, the contents of TNF-α, IL-6, IL-1β, MDA, and MMP9, and the expression levels of p-STAT3 and p-STAT5 in the HALI group were significantly increased. In contrast, the content of SOD and the expression of miR-21 were significantly decreased. Compared with the HALI group, the contents of TNF-α, IL-6, IL-1β, MDA, and MMP9 in the STAT3 inhibitor group and STAT5 inhibitor group were significantly decreased. At the same time, the content of SOD and the expression of miR-21 were significantly increased, especially in STAT3 inhibitor group [TNF-α (μg/L): 42.53±3.25 vs. 86.36±5.48, IL-6 (ng/L): 68.46±4.28 vs. 145.00±6.89, IL-1β (μg/L): 28.74±3.53 vs. 68.00±5.64, MDA (μmol/g): 20.33±2.74 vs. 42.58±3.45, and MMP9 (ng/L): 128.55±6.35 vs. 325.13±6.65, SOD (kU/g): 50.53±4.19 vs. 22.53±3.27, miR-21 (2 -ΔΔCt): 0.550±0.018 vs. 0.316±0.037, all P < 0.05]. Kaplan-Meier survival curve analysis showed that the 7-day cumulative survival rates of the STAT3 inhibitor group and STAT5 inhibitor group were significantly higher than those of the HALI group [62.5% (5/8), 37.5% (3/8) vs. 12.5% (1/8), both P < 0.05]. Conclusion:Inhibition of STAT3 hyperactivation may suppress the inflammatory response, regulate oxidative stress, improve lung permeability through regulating the expression of miR-21, which exert lung protection in HALI.

The alleviating effects of endothelial progenitor cells-derived exosomes on hyperoxia-induced injury of type Ⅱ alveolar epithelial cells in neonatal rats / 中国新生儿科杂志

Objective:To study the effects of endothelial progenitor cells (EPC)-derived exosomes on hyperoxia-induced injury in type Ⅱ alveolar epithelial cell (AECⅡ) in neonatal rats.Methods:EPCs of rats were cultured and exosomes were collected using Total Exosome Isolation kit. Primary cultured AECⅡof neonatal rats were randomly assigned into three groups: the control group, the hyperoxia group and the exosome group. The control group was cultured in room air with 5%CO 2, the hyperoxia group was cultured in 95%O 2 with 5%CO 2 and the exosome group was cultured with 0.1 mg/ml EPC-derived exosomes in 95%O 2 with 5%CO 2. Cell viability was detected using cell counting kit-8 (CCK-8) and apoptosis was detected using flow cytometry on d2, d4, and d6. Results:EPC-derived exosomes isolated from EPC culture supernatant were confirmed morphologically using transmission electron microscopy. After co-incubation of Dil-labeled EPC-derived exosomes with AEC Ⅱ for 24 h, Dil fluorescence was detected in the cytoplasm of AEC Ⅱ, indicating exosomes were uptaken by AEC Ⅱ. Compared with the control group, hyperoxia decreased cell viability and increased apoptosis of AEC Ⅱ and the injury was aggravated with the prolongation of hyperoxia duration ( P<0.001). Cell injury in the exosome group was milder than the hyperoxia group ( P<0.001). Compared with the control group, cell viability on d4 and d6 of hyperoxia was lower ( P=0.029 and 0.005 respectively) and cell apoptosis at d6 of hyperoxia was higher in the exosome group ( P=0.007). Conclusions:EPC-derived exosomes may partially attenuate hyperoxia-induced cell injury in neonatal rat AEC Ⅱ.

Short isocapnic hyperoxia affects indices of vascular remodeling and intercellular adhesion molecules in healthy men

In preparation for tracheal intubation during induction of anesthesia, the patient may be ventilated with 100% oxygen. To investigate the impact of acute isocapnic hyperoxia on endothelial activation and vascular remodeling, ten healthy young men (24±3 years) were exposed to 5-min normoxia (21% O2) and 10-min hyperoxia trials (100% O2). During hyperoxia, intercellular adhesion molecules (ICAM-1) (hyperoxia: 4.16±0.85 vs normoxia: 3.51±0.84 ng/mL, P=0.04) and tissue inhibitor matrix metalloproteinase 1 (TIMP-1) (hyperoxia: 8.40±3.84 vs normoxia: 5.73±2.15 pg/mL, P=0.04) increased, whereas matrix metalloproteinase (MMP-9) activity (hyperoxia: 0.53±0.11 vs normoxia: 0.68±0.18 A.U., P=0.03) decreased compared to the normoxia trial. We concluded that even short exposure to 100% oxygen may affect endothelial activation and vascular remodeling.

The role of polyomavirus enhancer activator 3 in hyperoxic-induced alveolar epithelial cells type Ⅱ injury / 中华实用儿科临床杂志

Objective:To investigate the role of polyomavirus enhancer activator 3 (PEA3) in hyperoxia-induced injury of type Ⅱ alveolar epithelial cells (AEC Ⅱ) and the underlying mechanism.Methods:AEC Ⅱ cells were cultured in vitro and divided into hyperoxia group and normoxia group.After 24 h, 48 h and 72 h of hyperoxia or air treatment, cells were collected and the best treatment time was selected at 48 h. AEC Ⅱ cells were divided into 3 groups: control group, negative control group (transfected with negative control) and PEA3 over expression group (transfected with PEA3 overexpression plasmid). Each group was further divided into hyperoxia subgroup and normoxia subgroup.Cells were harvested at 48 h after hyperoxia or normoxia treatment.Reactive oxygen species (ROS), Nod-like receptor domain 3 (NLRP3), monocyte chemoattractant protein-1 (MCP-1), interleukin(IL)-1β, IL-6, IL-8, IL-18, surfactant protein C (SP-C), aquaporins 5 (AQP5), PEA3 and manganese superoxide dismutase (MnSOD) levels were detected.Differences were compared by the t-test and repeated measures analysis of variance using SPSS 20.0 statistical software. Results:The interaction of grouping and treatment duration had significant effects on ROS, IL-1β, IL-6, IL-8, IL-18, SP-C and AQP5 levels in AEC Ⅱ cells ( F=19.857, 20.132, 23.133, 18.673, 28.341, 27.333 and 34.217, respectively, all P<0.05). At 24 h, 48 h and 72 h, ROS level in hyperoxia group was 1.78, 1.94 and 2.26 times higher than that in normoxia group ( t=18.649, 17.486 and 19.385, respectively all P<0.05). NLRP3 and MCP-1 levels were significantly upregulated in hyperoxia group.IL-1β level was 1.33, 1.69, and 1.65 times higher in hypoxia group at 24 h, 48 h and 72 h than that of normoxia group; IL-6 level was 1.26, 1.56 and 2.12 timers higher; IL-8 level was 1.13, 1.47 and 2.34 times higher; and IL-18 level was 1.46, 1.72 and 1.95 times higher, respectively (all P<0.05). The protein expression of SP-C was downregulated, while that of AQP5 was significantly upregulated in hypoxia group.The RNA expression of SP-C was 22%, 63% and 72% lower in hypoxia group than that in normoxia group at 24 h, 48 h and 72 h ( t=3.982, 16.328 and 20.259, P<0.05, respectively), and that of AQP5 was 1.92, 5.23 and 7.36 times higher ( t=14.631, 18.945 and 19.521, respectively, all P<0.05). There were significant differences in ROS, IL-1β, IL-6, IL-8, IL-18, SP-C and AQP5 levels at 24 h, 48 h and 72 h in hyperoxia group ( F=22.343, 20.566, 23.701, 19.222, 32.146, 40.278 and 37.107, respectively, all P<0.05). After 48 h of PEA3 overexpression, compared with the hyperoxic negative control group, ROS level in hyperoxic AEC Ⅱ cells overexpressing PEA3 decreased by 34% ( t=14.635, P<0.05). NLRP3 and MCP-1 were downregulated in hyperoxic AEC Ⅱ cells after overexpression of PEA3.IL-1β, IL-6, IL-8 and IL-18 levels decreased by 29%, 22%, 27% and 18%, respectively ( t=15.895, 17.872, 18.749 and 15.274, all P=0.000). SP-C was upre-gulated and AQP5 was downregulated by overexpression of PEA3 in hyperoxic AEC Ⅱ cells.In addition, PEA3 and MnSOD levels were significantly enhanced. Conclusions:Overexpression of PEA3 can alleviate the increase of ROS level in AEC Ⅱ cells, block the activation of various inflammatory pathways and reduce the transformation from AEC Ⅱ to AEC Ⅰ cells via enhancing MnSOD level.

Profibrotic effect of mast cells on hyperoxia-induced lung injury / 国际儿科学杂志

Bronchopulmonary dysplasia(BPD)is a chronic lung disease that usually occurs in premature infants who require mechanical ventilation, with a high mortality rate, and there is currently a lack of effective prevention and treatment methods.The pathological features of typical BPD are mainly severe airway injury, lung parenchymal inflammation, squamous epithelial metaplasia, and pulmonary fibrosis.Although the pathogenesis of BPD is not yet clear, a large number of mast cell aggregation can be observed in the fibrotic lung of premature infants.Studies have suggested that a series of inflammatory mediators released by mast cell degranulation under hyperoxia have an important impact on BPD.This article reviews the role and mechanism of mast cells in promoting fibrosis in BPD, and in order to provide new ideas for the treatment of BPD.

Role of the LRP1-pPyk2-MMP9 pathway in hyperoxia-induced lung injury in neonatal rats / 中国当代儿科杂志

OBJECTIVES@#To study the role of the low-density lipoprotein receptor-related protein 1 (LRP1)-proline-rich tyrosine kinase 2 phosphorylation (pPyk2)-matrix metalloproteinases 9 (MMP9) pathway in hyperoxia-induced lung injury in neonatal rats.@*METHODS@#A total of 16 neonatal rats were randomly placed in chambers containing room air (air group) or 95% medical oxygen (hyperoxia group) immediately after birth, with 8 rats in each group. All of the rats were sacrificed on day 8 of life. Hematoxylin and eosin staining was used to observe the pathological changes of lung tissue. ELISA was used to measure the levels of soluble LRP1 (sLRP1) and MMP9 in serum and bronchoalveolar lavage fluid (BALF). Western blot was used to measure the protein expression levels of LRP1, MMP9, Pyk2, and pPyk2 in lung tissue. RT-PCR was used to measure the mRNA expression levels of LRP1 and MMP9 in lung tissue.@*RESULTS@#The hyperoxia group had significantly higher levels of sLRP1 and MMP9 in serum and BALF than the air group (@*CONCLUSIONS@#The activation of the LRP1-pPyk2-MMP9 pathway is enhanced in hyperoxia-induced lung injury in neonatal rats, which may be involved in the pathogenesis of bronchopulmonary dysplasia.

Protective effect of adrenomedullin on hyperoxia-induced lung injury / 中国当代儿科杂志

OBJECTIVES@#To study the role of adrenomedullin (ADM) in hyperoxia-induced lung injury by examining the effect of ADM on the expression of calcitonin receptor-like receptor (CRLR), receptor activity-modifying protein 2 (RAMP2), extracellular signal-regulated kinase (ERK), and protein kinase B (PKB) in human pulmonary microvascular endothelial cells (HPMECs) under different experimental conditions.@*METHODS@#HPMECs were randomly divided into an air group and a hyperoxia group (@*RESULTS@#Compared with the air group, the hyperoxia group had significant increases in the mRNA and protein expression levels of ADM, CRLR, RAMP2, ERK1/2, and PKB (@*CONCLUSIONS@#ERK1/2 and PKB may be the downstream targets of the ADM signaling pathway. ADM mediates the ERK/PKB signaling pathway by regulating CRLR/RAMP2 and participates in the protection of hyperoxia-induced lung injury.

Anti-placental growth factor antibody ameliorates hyperoxia-mediated impairment of lung development in neonatal rats

This study investigates the effect of the overexpression of the placental growth factor (PGF) and hyperoxia on lung development and determines whether anti-PGF antibody ameliorates hyperoxia-mediated impairment of lung development in newborn rats. After exposure to normoxic conditions for seven days, newborn rats subjected to normoxia were intraperitoneally or intratracheally injected with physiological saline, adenovirus-negative control (Ad-NC), or adenovirus-PGF (Ad-PGF) to create the Normoxia, Normoxia+Ad-NC, and Normoxia+Ad-PGF groups, respectively. Newborn rats subjected to hyperoxia were intraperitoneally injected with physiological saline or anti-PGF antibodies to create the Hyperoxia and Hyperoxia+anti-PGF groups, respectively. Our results revealed significant augmentation in the levels of PGF and its receptor Flt-1 in the lung tissues of newborn rats belonging to the Normoxia+Ad-PGF or Hyperoxia groups. PGF overexpression in these groups caused lung injury in newborn rats, while anti-PGF antibody treatment significantly cured the hyperoxia-induced lung injury. Moreover, PGF overexpression significantly increased TNF-α and Il-6 levels in the bronchoalveolar lavage (BAL) fluid of the Normoxia+Ad-PGF and Hyperoxia groups. However, their levels were significantly reduced in the BAL fluid of the Hyperoxia+anti-PGF group. Immunohistochemical analysis revealed that PGF overexpression and hyperoxia treatment significantly increased the expression of the angiogenesis marker, CD34. However, its expression was significantly decreased upon administration of anti-PGF antibodies (compared to the control group under hyperoxia). In conclusion, PGF overexpression impairs lung development in newborn rats while its inhibition using an anti-PGF antibody ameliorates the same. These results provided new insights for the clinical management of bronchopulmonary dysplasia in premature infants.

Characteristics of electrophysiological changes in the process of astrocytes pyroptosis after hyperoxia exposure / 中南大学学报(医学版)

OBJECTIVES@#To observe the electrophysiological changes of astrocytes in the process of hyperoxia induced apoptosis and analyze the relationship between electrophysiological characteristics and morphological changes.@*METHODS@#Astrocytes were exposed to 90% hyperoxia for 12-72 h. The electrophysiological characteristics of astrocytes in each group were detected by patch clamp technique, and the morphological characteristics of astrocytes were observed at the same time. Then the same batch of astrocytes were collected, and the expression levels of caspase-1, caspase-3, gasdermin D (GSDMD) and gasdermin E (GSDME) were detected by Western blotting.@*RESULTS@#From 12 h to 72 h after hyperoxia exposure, the inward current was significantly lower than that of the control group (0.05). At each time point, the morphology of cells changed correspondingly. Western blotting showed that the expression of caspase-1 was increased significantly at 24 h and decreased significantly at 72 h after hyperoxia exposure (0.05), but began to decrease at 48 h (<0.05); GSDME increased gradually at 24 h after hyperoxia exposure (<0.05).@*CONCLUSIONS@#Under hyperoxia exposure, the ion channels of astrocytes are damaged, which can maintain the dysfunction of ion homeostasis, activate GSDME, induce the damaged cells to break away from the apoptotic pathway, and mediate the pyroptosis.

A clinical study on retinopathy of prematurity in a tertiary care centre

Background: Retinopathy of prematurity (ROP) is a multifactorial vasoproliferative retinal disorder that increases in incidence with decreasing gestational age. India shares 20% of the world childhood blindness. Besides congenital cataract, congenital glaucoma and ocular injuries, ROP is emerging as one of the important causes of childhood blindness in India.Methods: This hospital based prospective study was undertaken during October 2016 to September 2018 in the Department of Ophthalmology, SCB Medical College. Authors included (a) all preterm infants weighing less than 1750gm or gestational age less than 34 weeks at birth, (b) infants with birth weight between 1750gm to 2000gm and gestational age more than 34 weeks (late preterm and term infants) those were considered as high risk.Results: Among the 328 babies included in our study, the incidence of ROP was 29.57%. Bilateral ROP was found in 76.29% with nearly equal stages in both eyes and only 23 neonates showed unilateral involvement.Conclusions: Low birth weight, lower gestational age, blood transfusion, Respiratory Distress Syndrome (RDS), apnoea, supplemental oxygen therapy, maternal anaemia and gestational diabetes mellitus (GDM) were strongly associated with development of ROP.

¿El licopeno puede eliminar los efectos perjudiciales de la hiperoxia en los cerebros inmaduros? / Can lycopene eliminate the harmful effects of hyperoxia in an immature brain?

Objetivos: Al ser un antioxidante, el licopeno protege a las células contra el daño causado por los radicales libres, fortalece los enlaces intercelulares y mejora el metabolismo celular. Este estudio analiza los efectos del licopeno sobre los trastornos neurodegenerativos por hiperoxia en ratas recién nacidas a término. Métodos: Estas ratas se dividieron en cuatro grupos: grupo 1 de referencia con normoxia, grupo 2 con normoxia + licopeno, grupo 3 de referencia con hiperoxia y grupo 4 con hiperoxia + licopeno. Los grupos 1 y 2 se supervisaron en condiciones de aire ambiental, y los grupos 3 y 4 se supervisaron con un nivel de oxígeno > 85 % O2. Los grupos 2 y 4 recibieron inyecciones intraperitoneales de licopeno de 50 mg/kg/día; los otros grupos recibieron inyecciones intraperitoneales de aceite de maíz con el mismo volumen. Las ratas se sacrificaron en el día 11, después de 10 días con hiperoxia. Se extrajeron los cerebros, y se evaluaron los parámetros del sistema oxidativo. Resultados: Se detectaron lesiones cerebrales por hiperoxia en sustancia blanca, regiones corticales y tálamo. Aumentó la cantidad de células apoptóticas y disminuyó la cantidad de células PCNA positivas en los grupos 3 y 4, comparados con el grupo 1. No se observó una mejora significativa en la cantidad de células apoptóticas y células PCNA positivas en los grupos 3 y 4; además, aumentó la apoptosis. Conclusión: Se halló que el licopeno no mostró efectos terapéuticos para el daño cerebral en ratas recién nacidas. Además, se demostró que el licopeno podría causar efectos tóxicos.

Objectives. In addition to protecting cells against free radical harm thanks to its anti-oxidant nature, lycopene strengthens the bonds among cells and improves cell metabolism. This study focuses on analyzing therapeutic effects of lycopene in hyperoxia-induced neurodegenerative disorders in newborn rats. Methods. Term newborn rats were divided into four groups as the normoxia control group (group-1), normoxia+lycopene group (group-2), hyperoxia control group (group-3) and hyperoxia+lycopene group (group-4). Group-1 and group-2 were monitored in room air while the group-3 and group-4 were monitored at > 85% O2. The group-2 and group-4 were injected with lycopene intrapertioneally (i.p. ) at 50mg/kg/day while the other groups were injected with corn oil i.p. at the same volume. The rats we sacrificed on the 11th day following the 10-day hyperoxia. The brains were removed and oxidant system parameters were assessed. Results. Injury resulting from hyperoxia was detected in the white matter, cortical regions, and thalamus of the brains. It was observed that the number of apoptotic cells increased and the number of proliferating cell nuclear antigen (PCNA) positive cells decreased in the groups-3 and 4 compared to the group-1. No significant improvement in the number of apoptotic cells and PCNA positive cells was observed in the groups-3 and 4, and apoptosis increased as well. Conclusion. This study found that lycopene, did not show any therapeutic effects for brain damage treatment in newborn rats. In addition, this study demonstrated that lycopene might lead to toxic effects.

Intervention effect of glutamine on hyperoxia lung injury in neonatal rats and its mechanism / 吉林大学学报(医学版)

Objective: To explore the protective effect of glutamine (GLN) on the hyperoxia lung injury in the neonatal rats, and to elucidate its mechanism. Methods: A total of 90 male and female Wistar rats were selected and randomly divided into control group (FiO2: = 21%). hyperoxia group ( FiO2: > 85%) and hyperioxia + glutamine (GLN) group (FiO2: > 85%) (n=30). The rats in hyperioxia group and hyperioxia + GLN groups were used to establish the models of hyperoxia lung injury (HALI). The rats in hyperoxia+ GLN group were intraperitoneally injected with 0. 75 g • kg-1 • d-1 GLN from the first day of experiment, and the rats in other two groups were abdominally injected with the same volume of normal saline. The body weights, water contents in the lung tissue of the neonatal rats in various groups on the 3rd. 7th. and 14th days of the experiment were measured. I IF staining was used to determine the morphology of lung tissue of the rats in various groups; ELISA was used to detect the levels of interleukin-6 (IL-6)∗ interleukin-1|ß (IL-lf3) and tumor necrosis factor-a (TNF-a) in the lung tissue homogenate of the rats in various groups. Results: Compared with control group at the same time, the weights of the neonatal rats in hyperoxia group were significantly decreased on the 3rd. 7th and 14th days ( P∗CO. 05); the body weights of neonatal rats in hyperoxia + GLN group were significantly higher than those in hyperoxia group at the same time (P<0. 05). On the 3rd. 7th. and 14th days, the water contents of lung tissue of the rats in hyperoxia group were higher than those in control group at the same time ( P< 0. 05). and the difference was gradually increased with the prolongation of time; the water contents of lung tissue of the rats in hyperoxia • GLN group were significantly lower than those in hyperoxia group ( P

Effect of deferoxamine on hyperoxic lung injury in rats / 中华麻醉学杂志

Objective@#To evaluate the effect of deferoxamine on hyperoxic lung injury in rats.@*Methods@#Twenty-four adult male Sprague-Dawley rats, weighing 170-230 g, were divided into 3 groups (n=8 each) using a random number table method: hyperoxia group (group H), deferoxamine group (group D) and air control group (group C). Mechanical ventilation was performed after tracheal intubation, group C inhaled air, and H and D groups inhaled 90% oxygen.Deferoxamine 50 mg·kg-1·h-1 was continuously infused via the tail vein for 4 h via the tail vein at the same time of mechanical ventilation in group D. The equal volume of normal saline was infused in H and C groups.At 4 h of mechanical ventilation, lungs were removed for examination of pathological changes of lung tissues and for determination of wet/dry weight ratio (W/D ratio) and levels of pulmonary surfactant protein C (SP-C), xanthine oxidase (XOD) and glutathione reductase (GR) in lung tissues and broncho-alveolar lavage fluid (BALF) were detected by enzyme-linked immunosorbent assay.@*Results@#Compared with group C, the pathological score of lung tissues and W/D ratio were significantly increased, the levels of SP-C and GR in lung tissues and BALF were decreased, and the level of XOD in lung tissues and BALF was increased in H and D groups (P<0.05). Compared with group H, the pathological score of lung tissues and W/D ratio were significantly decreased, the levels of SP-C and GR in lung tissues and BALF were increased, and the level of XOD in lung tissues and BALF was decreased in group D (P<0.05).@*Conclusion@#Deferoxamine can inhibit oxidative stress response and alleviate hyperoxic lung injury in rats.

Effect of hyperoxia exposure on expression of microRNA-125b and tumor necrosis factor alpha, interleukin-6 in lung tissues of premature newborn rats / 中华实用儿科临床杂志

Objective@#To observe the expression of microRNA-125b (miR-125), tumor necrosis factor alpha (TNF-α) and interleukin-6(IL-6) in premature rats exposed to hyperoxia.@*Methods@#Eighty 1-day old Sprague Dawley (SD) rats were randomly divided into an air group and a hyperoxia group.The rats in the hyperoxia group were continuously exposed to oxygen chamber for 1-3 L/min, oxygen volume fraction was maintained at (800±50) mL/L, and the rats in air group were placed in the same room with the oxygen volume fraction at 210 mL/L.The feeding conditions were same in 2 groups.Lung tissues of premature rats were extracted at different time (1, 4, 7, 10, 14 days). The pathologic changes in the lung tissues were observed by hematoxylin-eosin (HE) staining.The levels of miR-125b and TNF-α, IL-6 in lung tissues were detected by reverse transcription polymerase chain reaction (qRT-PCT) and enzyme-linked immunosorbent assay (ELISA).@*Results@#Compared with the air group, miR-125b in the hyperoxia group increased slowly after day 1, reached the highest in day 10 (2.554±0.323), and the relative expression in day 14 decreased slightly(2.329±0.263), and there were significant differences between 2 groups at di-fferent time (all P<0.05); in particular TNF-α level increased in day 7 [(78.55±39.53) ng/L], and reached the peak at day 10 [(80.16±11.24) ng/L], and there was a significant difference(P<0.05); IL-6 levels increased at day 7 [(45.44±31.94) ng/L], and reached the peak at day 10 [(90.38±8.24) ng/L], and there was a significant difference(P<0.05). There was a no significant correlation between miR-125b and TNF-α in the hyperoxia groups (r=0.132, P>0.05), but there was significant correlation between miR-125b and IL-6 in hyperoxia groups(r=0.439, P<0.05).@*Conclusions@#The levels of miR-125b, TNF-α and IL-6 are involved in the pathological process of bronchopulmonary dysplasia induced by hyperoxia, and IL-6 may be the key factor for miR-125b.

Study on the expression level of zonula occludens 1 and zonula occludens 1 related nucleic acid binding protein in alveolar epithelial cells in hyperoxia induced bronchopulmonary dysplasia newborn rats / 中国小儿急救医学

Objective@#Previous studies have found abnormal proliferation and transdifferentiation of alveolar epithelial cells(AECs)in hyperoxic lung injury of neonatal rats.The purpose of this study was to clarify the expression of zonula occludens 1(ZO-1) and ZO-1 related nucleic acid binding protein(ZONAB)in AECs in hyperoxic lung injury model, in order to investigate its effect on the proliferation and transdifferentiation of AECs in the injured lung tissue.@*Methods@#Full-term neonatal Wistar rats were randomly divided into two groups within 12 h after birth, model group(inhaled oxygen concentration 85%)and control group(inhaled air). Lung specimens were collected at 7, 14 and 21 days after exposure.The expression of ZONAB in typeⅡalveolar epithelial cells(AECⅡ)was observed by double immunofluorescence staining.At the same time, AEC Ⅱ was isolated from lung tissues of animal models at these time points, and the expression levels of ZO-1, ZONAB protein and mRNA in lung tissues and AECⅡof the two groups were detected by Western blot and Real-Time PCR.In addition, AEC Ⅱ was isolated from lung tissue of normal newborn rats and then divided into model group(85% oxygen concentration)and control group(21% oxygen concentration). After 48 hours of culture in vitro, the expression levels of ZO-1, ZONAB protein and mRNA were detected, and the expression level and location of ZONAB were observed by immunofluorescence staining.@*Results@#Double immunofluorescence staining showed that the expression of ZONAB in AECⅡin model group was significantly lower than that in control group.The protein and mRNA expression levels of ZO-1 and ZONAB in AECⅡisolated from lung tissue of model group were both significantly lower than those from control group, starting from 7 d after hyperoxia exposure.AECⅡisolated from lung tissue of normal newborn rats, were then incubated for 48 hours under hyperoxia or normoxia in vitro, the protein and mRNA expression levels of ZO-1 and ZONAB significantly decreased in model group compared with those in control group.The results of immunofluorescence staining showed that the expression of ZONAB was higher in AECⅡof the control group, and ZONAB was mostly located in the junction and nucleus of cells, while the expression of ZONAB in the model group significantly decreased than that in the control group, and the expression sites were clustered in the cytoplasm, with little expression in the junction and nucleus.@*Conclusion@#ZO-1, as a tight junction-related protein, is down-regulated in hyperoxic lung injury model.In addition to destroying pulmonary epithelial barrier to mediate pulmonary edema, it also participated in the regulation of proliferation and differentiation of AECs by regulating transcription factor ZONAB, suggesting that this may be another pathway leading to hyperoxic lung injury.

Role of necroptosis in hyperoxia-induced acute lung injury in preadolescent rats / 中华麻醉学杂志

Objective@#To evaluate the role of necroptosis in hyperoxia-induced acute lung injury (ALI) in preadolescent rats.@*Methods@#A total of 72 clean-grade healthy male Sprague-Dawley rats, aged 14 days, weighing 40-50 g, were divided into 3 groups (n=24 each) by using a random number table method: control group (group C), hyperoxia-induced ALI group (group ALI) and hyperoxia-induced ALI and necrostatin-1 group (group ALI+ N). The rats of group ALI+ N was intraperitoneally injected with necrostatin-1 1.0 mg/kg once a day for 3 consecutive days.The rats were intraperitoneally injected with dimethyl sulfoxide 0.2 ml/kg once a day for 3 consecutive days in C and ALI groups.The animals were sacrificed at 72 h after inhaling oxygen, and bronchoalveolar lavage fluid (BALF) was collected for determination of interleukin-6 (IL-6) and IL-8 concentrations (by enzyme-linked immunosorbent assay), superoxide dismutase (SOD) activity (by xanthine oxidase method), and malondialdehyde (MDA) concentration (by thiobarbituric acid method). Lung tissues were taken for measurement of wet/dry weight ratio (W/D ratio) and for examination of the pathological changes (with a light microscope) and ultrastructure of lung tissues (with an electron microscope). The injured alveolus rate (IAR) was calculated.The expression of receptor-interacting protein kinase 1 (RIPK1), RIPK3 and mixed-lineage kinase domain-like protein (MLKL) in lung tissues was detected by Western blot.@*Results@#Compared with group C, the concentrations of IL-6, IL-8 and MDA in BALF were significantly increased, the activity of SOD in BALF was decreased, the W/D ratio and IAR of lung tissues were increased, the expression of RIPK1, RIPK3 and MLKL in lung tissues was up-regulated (P<0.05), and the pathological damage was accentuated in group ALI.Compared with group ALI, the concentrations of IL-6, IL-8 and MDA in BALF were significantly deceased, the activity of SOD in BALF was increased, the W/D ratio and IAR of lung tissues were decreased, the expression of RIPK1, RIPK3 and MLKL in lung tissues was down-regulated (P<0.05), and the pathological damage was significantly attenuated in group ALI+ N.@*Conclusion@#Necroptosis is involved in the pathophysiological process of hyperoxia-induced ALI in preadolescent rats.

Role of necroptosis in hyperoxia-induced acute lung injury in preadolescent rats / 中华麻醉学杂志

Objective To evaluate the role of necroptosis in hyperoxia-induced acute lung injury(ALI)in preadolescent rats.Methods A total of 72 clean-grade healthy male Sprague-Dawley rats,aged 14 days,weighing 40-50 g,were divided into 3 groups(n＝24 each)by using a random number table method: control group(group C),hyperoxia-induced ALI group(group ALI)and hyperoxia-induced ALI and necrostatin-1 group(group ALI+N).The rats of group ALI+N was intraperitoneally injected with ne-crostatin-1 1.0 mg/kg once a day for 3 consecutive days.The rats were intraperitoneally injected with dime-thyl sulfoxide 0.2 ml/kg once a day for 3 consecutive days in C and ALI groups.The animals were sacrificed at 72 h after inhaling oxygen,and bronchoalveolar lavage fluid(BALF)was collected for determination of interleukin-6(IL-6)and IL-8 concentrations(by enzyme-linked immunosorbent assay),superoxide dis-mutase(SOD)activity(by xanthine oxidase method),and malondialdehyde(MDA)concentration(by thiobarbituric acid method).Lung tissues were taken for measurement of wet/dry weight ratio(W/D ratio)and for examination of the pathological changes(with a light microscope)and ultrastructure of lung tissues(with an electron microscope).The injured alveolus rate(IAR)was calculated.The expression of recep-tor-interacting protein kinase 1(RIPK1),RIPK3 and mixed-lineage kinase domain-like protein(MLKL)in lung tissues was detected by Western blot.Results Compared with group C,the concentrations of IL-6,IL-8 and MDA in BALF were significantly increased,the activity of SOD in BALF was decreased,the W/D ratio and IAR of lung tissues were increased,the expression of RIPK1,RIPK3 and MLKL in lung tis-sues was up-regulated(P＜0.05),and the pathological damage was accentuated in group ALI.Compared with group ALI,the concentrations of IL-6,IL-8 and MDA in BALF were significantly deceased,the ac-tivity of SOD in BALF was increased,the W/D ratio and IAR of lung tissues were decreased,the expres-sion of RIPK1,RIPK3 and MLKL in lung tissues was down-regulated(P＜0.05),and the pathological damage was significantly attenuated in group ALI+N.Conclusion Necroptosis is involved in the patho-physiological process of hyperoxia-induced ALI in preadolescent rats.