The need for mechanical ventilation due to severe hypoxemia and acute respiratory distress syndrome has increased dramatically in the global pandemic of severe respiratory infectious diseases. In clinical scenarios, it is sometimes necessary to briefly disconnect the ventilator pipeline from the artificial airway. Still, this operation can lead to a sharp drop in airway pressure, which is contrary to the protective lung ventilation strategy and increases the risk of environmental exposure to bioaerosol, posing a serious threat to patients and medical workers. At present, there is yet to be a practical solution. A new artificial airway device was designed by the medical staff from the department of critical care medicine of Beijing Tiantan Hospital, Capital Medical University, based on many years of research experience in respiratory support therapy, and recently obtained the National Utility Model Patent of China (ZL 2019 2 0379605.4). The device comprises two connecting pipes, the sealing device body, and the globe valve represented by the iridescent optical ring. It has a simple structure, convenient operation, and low production cost. The device is installed between the artificial airway and the ventilator pipeline and realizes the instantaneous sealing of the artificial airway by adjusting the shut-off valve. Using this device to treat mechanically ventilated patients can minimize the ventilator-induced lung injury caused by the repeated disconnection of pipelines, avoid iatrogenic transmission of bioaerosols, and realize dual protection for patients and medical workers. It has extensive clinical application prospects and high health and economic value.
Humans ; Respiration, Artificial/adverse effects* ; Ventilators, Mechanical/adverse effects* ; Respiratory Distress Syndrome/therapy* ; Ventilator-Induced Lung Injury/prevention & control* ; Hypoxia/complications*

Radiation therapy is one of the main treatment methods for patients with thoracic malignant tumors, which can effectively improve the survival rate of the patients. However, radiation therapy can also cause damage to normal tissues while treating tumors, leading to radiation-induced lung injury such as radiation pneumonia and pulmonary fibrosis. Radiation-induced lung injury is a complex pathophysiological process involving many factors, and its prevention and treatment is one of the difficult problems in the field of radiation medicine. Therefore, the search for sensitive predictors of radiation-induced lung injury can guide clinical radiotherapy and reduce the incidence of radiation-induced lung injury. With the in-depth study of intestinal flora, it can drive immune cells or metabolites to reach lung tissue through the circulatory system to play a role, and participate in the occurrence, development and treatment of lung diseases. At present, there are few studies on intestinal flora and radiation-induced lung injury. Therefore, this paper will comprehensively elaborate the interaction between intestinal flora and radiation-induced lung injury, so as to provide a new direction and strategy for studying the protective effect of intestinal flora on radiation-induced lung injury.
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Humans ; Lung Injury/prevention & control* ; Gastrointestinal Microbiome ; Lung Neoplasms/radiotherapy* ; Lung/pathology* ; Radiation Injuries/metabolism* ; Thoracic Neoplasms

Objective To observe the role of tumor necrosis factor-α (TNF-α) and platelet-derived growth factor-B (PDGF-B) in kiwi fruit essence-mediated protection of radiation-induced lung injury (RILI) in rats. Methods 96 male healthy Sprague-Dawley rats were divided into normal control group, model group, and kiwi fruit essence treatment group(60 and 240 mg/kg) by the random number table method, with 24 animals in each group. The whole lungs underwent 6 MV X-ray irradiation (18 Gy) to induce RILI animal models in rats of the latter three groups. On the next day after irradiation, rats in the latter two groups were intragastrically administrated with 60 or 240 mg/kg kiwi fruit essence, once a day. The rats in the normal control and model groups were treated with 9 g/L sodium chloride solution. Eight rats in the latter three groups were randomly sacrificed on days 14, 28, and 56, while normal control rats were sacrificed on day 56 as the overall control. Blood samples were collected and separated. Serum concentrations of TNF-α and PDGF-B were detected using ELISA. The lung tissues were isolated for HE and Masson staining to evaluate alveolitis and pulmonary fibrosis (PF). The hydroxyproline (HYP) content in lung tissues was detected. The mRNA and protein expression of pulmonary TNF-α and PDGF-B were determined by quantitative real-time PCR and immunohistochemistry. Results Compared with the model group, treatment with 60 and 240 mg/kg kiwi fruit essence group significantly reduced alveolitis on days 14 and 28 as well as PF lesions on days 28 and 56. Compared with the normal control group, HYP content in the lung tissue of the model group increased on day 28 and day 56, while TNF-α and PDGF-B levels in the serum and lung tissues increased at each time point. Compared with the model group during the same period, 60 and 240 mg/kg kiwi fruit essence element treatment group reported the diminished levels of serum and pulmonary TNF-α on day 14 and day 28. Consistently, the lung tissue HYP content and serum and pulmonary PDGF-B levels on day 28 and day 56 were reduced. In addition, the above indicators in the 240 mg/kg kiwi fruit essence treatment group were lower than those for the 60 mg/kg kiwi fruit essence treatment group. Conclusion Kiwi fruit essence can alleviate RILI in rats, which is related to the down-regulation of TNF-α expression at the early stage and decreased PDGF-B level at the middle and late stages.
Animals ; Male ; Rats ; Fruit/metabolism* ; Lung/radiation effects* ; Lung Injury/prevention & control* ; Oils, Volatile ; Proto-Oncogene Proteins c-sis/metabolism* ; Pulmonary Fibrosis ; Rats, Sprague-Dawley ; Tumor Necrosis Factor-alpha/metabolism* ; Actinidia/chemistry*

Our previous studies have shown that calcitonin gene-related peptide (CGRP) exerts protective effects on the acute lung injury induced by oxidative stress. This study was aimed to investigate whether autophagy was involved in the protection of CGRP against oxidative stress-induced lung injury in neonatal rats. Newborn Sprague-Dawley (SD) rats were randomly divided into five groups: Control group, oxidative stress model group (Model group), Model + CGRP group, Model + CGRP + Rapamycin (an autophagy agonist) group, and Model + CGRP + LY294002 (an autophagy inhibitor) group. The model of hyperoxia-induced lung injury was established by continuous inhalation of oxygen (FiO₂ = 90%-95%) for 14 days in neonatal SD rats. Pathological changes of lung tissue were observed by hematoxylin and eosin (HE) staining, and mean linear intercept (MLI) was measured. The quantitative changes of autophagic vesicles (AV) in type II alveolar epithelial cells (AECII) were measured under the transmission electron microscope. The protein expressions of Caspase-3, Bcl-2, mTOR, and Beclin-1 in lung tissue lysates were detected by Western blot. The results showed that, compared to the Model group at the same time point, the number of AV in AECII and the expression level of Beclin-1 protein of the lung tissue were increased, while the expression level of mTOR protein was decreased, with alleviated pathological changes, reduced MLI value and Caspase-3 protein expression level, increased Bcl-2 protein expression level in the lung tissue of Model + CGRP group. In addition, we found that the protective effect of CGRP on hyperoxia-induced lung injury could be enhanced by autophagy activator Rapamycin and abolished by autophagy inhibitor LY294002. Together, these findings indicate that CGRP could attenuate hyperoxia-induced lung injury in neonatal rats by enhancing autophagy.
Acute Lung Injury/pathology* ; Animals ; Animals, Newborn ; Autophagy ; Calcitonin/metabolism* ; Calcitonin Gene-Related Peptide/metabolism* ; Caspase 3/metabolism* ; Hyperoxia/pathology* ; Lung/pathology* ; Lung Injury/prevention & control* ; Oxidative Stress ; Proto-Oncogene Proteins c-bcl-2/metabolism* ; Rats ; Rats, Sprague-Dawley ; Sirolimus/pharmacology*

OBJECTIVE: To elucidate the pathogenic role of leukotriene B4 (LTB4) in pulmonary hyper-permeability and inflammation induced by lung-protective mechanical ventilation (LPMV) in rabbits. METHODS: Thirty-two healthy Japanese white rabbits were randomized into 4 groups for treatment with vehicle or bestatin (a leukotriene A4 hydrolase inhibitor that inhibits LTB4 production) administered intragastrically at the daily dose of 8 mg/kg for 5 days, followed by sham operation (group S and group BS, respectively, in which the rabbits were anesthetized only) or LPMV (group PM and group BPM, respectively, in which the rabbits received ventilation with 50% oxygen at a tidal volume of 8 mL/kg for 5 h). The concentrations of LTB4 and cyclic adenosine monophosphate (cAMP) in the lung tissues were analyzed by ELISA. cAMP content, protein kinase A (PKA) protein expression and the Rap1-GTP protein to total Rap1 protein ratio were determined to assess the activities of cAMP/PKA and Rap1 signaling pathways. The lung injury was evaluated by assessing lung permeability index, lung wet/dry weight ratio, polymorphonuclear leukocyte (PMN) count in bronchoalveolar lavage fluid (BALF), pulmonary myeloperoxidase (MPO) activity and lung histological scores. RESULTS: None of the examined parameters differed significantly between group S and group BS. All the parameters with the exception of lung histological score increased significantly in group PM and group BPM as compared to those in group S ( CONCLUSIONS LPMV can induce LTB4 overproduction to down-regulate cAMP/PKA and Rap1 signaling pathways in the lungs of rabbits, which results in lung hyper-permeability and inflammation. Bestatin can inhibit LTB4 production in the lungs to protect against LPMV-induced lung hyper-permeability and inflammation.
Animals ; Bronchoalveolar Lavage Fluid ; Leukotriene B4 ; Lung ; Lung Injury/prevention & control* ; Neutrophils ; Rabbits ; Respiration, Artificial/adverse effects*

OBJECTIVE: To assess the effect of neutralizing CD96 on natural killer (NK) cell functions in mice with pulmonary infection and explore the possible mechanism. METHODS: Male BALB/c mice were randomly divided into infection group (Cm group), anti-CD96 treatment group (anti-CD96 group) and control group (=5). In the former two groups, was inoculated intranasal administration to establish mouse models of pulmonary infection, and the mice in the control group received intranasal administration of the inhalation buffer. In anti-CD96 group, the mice were injected with anti-CD96 antibody intraperitoneally at the dose of 250 μg every 3 days after the infection; the mice in Cm group received intraperitoneal injections of saline. The body weight of the mice was recorded daily. The mice were sacrificed 5 days after infection, and CD96 expression was detected by quantitative real-time PCR and Western blotting. HE staining and pathological scores were used to evaluate pneumonia of the mice. The inclusion body forming units (IFUs) were detected in the lung tissue homogenates to assess lung tissue chlamydia load. Flow cytometry and ELISA were used to assess the capacity of the lung NK cells to produce interferon-γ (IFN-γ) and regulate macrophages and Th1 cells. RESULTS: infection inhibited CD96 expression in NK cells of the mice. Compared with those in Cm group, the mice in antiCD96 mice showed significantly milder lung inflammation ( < 0.05) and reduced chlamydia load in the lung tissue ( < 0.05). Neutralizing CD96 with anti-CD96 significantly enhanced IFN-γ secretion by the NK cells ( < 0.05) and augmented the immunoregulatory effect of the NK cells shown by enhanced responses of the lung macrophages ( < 0.05) and Th1 cells ( < 0.05). CONCLUSIONS Inhibition of CD96 alleviates pneumonia in -infected mice possibly by enhancing IFN-γ secretion by NK cells and augmenting the immunoregulatory effect of the NK cells on innate and adaptive immunity.
Animals ; Antigens, CD ; metabolism ; Chlamydia Infections ; complications ; immunology ; physiopathology ; Chlamydia muridarum ; Interferon-gamma ; genetics ; metabolism ; Killer Cells, Natural ; metabolism ; Lung Injury ; etiology ; genetics ; prevention & control ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Inbred C57BL

OBJECTIVE: To investigate the effects of Hippo signaling pathway on lung injury repair of mesenchymal stem cells (MSC) in acute respiratory distress syndrome (ARDS) and its mechanism. METHODS: Mouse bone marrow-derived MSC (mMSCs) cell lines with low expression of large tumor suppressor 2 (LATS2) were constructed by lentiviral vector transfection. Male C57BL/6 mice aging 6-8 weeks old were divided into four groups according to random number table (n = 36). The ARDS animal model (ARDS group) was reproduced by intratracheally injection of 2 g/L lipopolysaccharide (LPS) 50 μL, the normal saline (NS) control group was injected with an equal volume of NS. After 4 hours of model reproduction, 5×10⁴ mMSCs transfected with blank lentivirus vector (MSC-shcontrol group) or shLATS2 lentivirus vector (MSC-shLATS2 group) were transplanted intratracheally, while NS control group and ARDS group were injected with equal volume of phosphate buffered saline (PBS). Mice were sacrificed at 3, 7, and 14 days after modeling, and lung tissue and bronchoalveolar lavage fluid (BALF) were harvested. Near-infrared fluorescence imaging, immunofluorescence staining and Western Blot were used to track mMSCs in lung tissue. Retension and proportion of mMSC differentiation into type II alveolar epithelial cells (AEC II) were evaluated. Lung tissue wet weight/body weight ratio (LWW/BW) and total protein (TP) and albumin (ALB) in BALF were determined to reflect pulmonary edema. The expression of Occludin protein in lung epithelium was tested by Western Blot to reflect permeability of epithelium. The levels of interleukins (IL-1β, IL-6, IL-10) in BALF were assessed by enzyme-linked immunosorbent assay (ELISA) to reflect lung inflammation. Hematoxylin-eosin (HE) staining and modified Masson staining were carried out, and the scores were assessed to reflect lung injury and evaluate pulmonary fibrosis. RESULTS: The signal intensity of isolated lung fluorescence images at 3 days in the MSC-shLATS2 group was significantly higher than that in the MSC-shcontrol group (fluorescence intensity: 0.039±0.005 vs. 0.017±0.002, P < 0.05), the number of green fluorescent protein (GFP)-positive cells in lung tissue was also significantly higher than that in the MSC-shcontrol group (cells/HP: 29.65±6.98 vs. 17.50±4.58, P < 0.05), but they all decreased with time; and the proportion of mMSCs differentiated into AEC II was significantly increased [(64.12±15.29)% vs. (19.64±3.71)%, P < 0.05]. Compared with the NS control group, the levels of surface active protein C (SPC) and Occludin protein in the ARDS group were significantly decreased, LWW/BW ratio and TP, ALB and inflammatory factors levels in BALF were significantly increased; extensive alveolar and interstitial edema, hemorrhage and diffuse inflammatory cell infiltration were found in lung tissue, and the lung injury score was significantly increased; collagen fibers were deposited in alveolar septum and alveolar cavity, and pulmonary fibrosis score was also increased significantly. Compared with the ARDS group, the expression levels of SPC and Occludin at 14 days in the MSC-shcontrol group and the MSC-shLATS2 group were significantly increased (SPC/β-actin: 0.51±0.12, 0.68±0.10 vs. 0.27±0.08, Occludin/β-actin: 0.49±0.19, 0.79±0.11 vs. 0.25±0.08, all P < 0.05), TP, ALB, IL-1β, IL-6 levels in BALF at 3 days were significantly decreased [TP (g/L): 8.08±1.72, 5.12±0.87 vs. 12.55±2.09; ALB (g/L): 0.71±0.21, 0.44±0.18 vs. 1.18±0.29, IL-1β (ng/L): 99.26±14.32, 60.11±8.58 vs. 161.86±25.17, IL-6 (ng/L): 145.54±13.29, 101.74±11.55 vs. 258.79±27.88, all P < 0.05], and IL-10 was significantly increased (ng/L: 190.83±22.61, 316.65±37.88, both P < 0.05). Furthermore, all the above parameters in the MSC-shLATS2 group were significantly improved as compared with those in the MSC-shcontrol group (all P < 0.05). LWW/BW ratio in the MSC-shLATS2 group was significantly lower than that in the ARDS group and the MSC-shcontrol group (mg/g: 9.85±1.51 vs. 16.78±1.92, 14.88±1.74, both P < 0.05). CONCLUSIONS Inhibiting Hippo signaling pathway by low expression of LATS2 could promote the retention of mMSCs in lung tissue and differentiation into AEC II cells of ARDS mice, improve pulmonary edema and alveolar epithelial permeability, regulate pulmonary inflammatory response, and alleviate pathological damage and fibrosis of lung tissue.
Animals ; Hippo Signaling Pathway ; Lung Injury/prevention & control* ; Male ; Mesenchymal Stem Cells/metabolism* ; Mice ; Mice, Inbred C57BL ; Protein Serine-Threonine Kinases/metabolism* ; Respiratory Distress Syndrome/metabolism* ; Signal Transduction

To establish rat model of lung ischemia/reperfusion (IR) in vivo, and to explore the effects of acidification pretreatment for respiratory acidosis on the expression of matrix metalloproteinase-9 (MMP-9) and the possible mechanisms.
 Methods: A total of 36 male Sprague-Dawley rats were divided into a sham group (S group), a IR group, and an experiment group (RA group) (n=12 in each group). The rat left lung hilum in the S group was dissociated, followed by perfusion without ischemia. After the left lung hilum in the IR group was blocked for 45 min, the rats were followed by reperfusion for 180 min. After left lung hilum in the RA group was dissociated, the respiratory parameters were adjusted so that pressure of end tidal carbon dioxide (PETCO2) reached 56-65 mmHg (1 mmHg=0.133 kPa) for 5 min, then the rats was subjected to IR. Lung tissue wet/dry (W/D) and lung permeability index (LPI) were calculated, while the lung histopathology was observed and the MMP-9 protein expression were measured.
 Results: Compared with the control group, the W/D and LPI in the IR group and the RA group increased after reperfusion (both P<0.05), and the levels of W/D and LPI in the group RA were lower than that in the IR group (P<0.05). LPI and pathology scores were significantly lower in the RA group than those in the IR group (both P<0.01). After IR, the expression of MMP9 in the lung tissues in the IR group and the RA group increased significantly (both P<0.01). The expression of MMP-9 protein in the RA group was significantly lower than that in the IR group (P<0.01).
 Conclusion: After lung IR injury, the expression of MMP-9 protein, vascular permeability and inflammatory exudation is increased. The acidification pretreatment for respiratory acidosis can inhibit the expression of MMP-9 protein and reduce inflammatory exudation after lung IR, showing a protective effect on lung IR injury.
Acidosis, Respiratory ; drug therapy ; prevention & control ; Animals ; Gene Expression Regulation, Enzymologic ; drug effects ; Lung ; enzymology ; Lung Injury ; enzymology ; Male ; Matrix Metalloproteinase 9 ; genetics ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; drug therapy ; prevention & control

We recently established a novel disease entity presented as progressive respiratory failure associated with the inhalation of humidifier disinfectants. In April 2011, we encountered a series of peripartum patients with complaints of respiratory distress of unknown etiology, which was an uncommon phenomenon. Accordingly, we created a multidisciplinary team comprising intensivists, radiologists, pathologists, epidemiologists, and the Korea Centers for Disease Control and Prevention (KCDC). Further, we defined the disease entity and performed a case-control study, epidemiologic investigation, and animal study to determine the etiology. The study findings indicated that the lung injury outbreak was related to the inhalation of humidifier disinfectants and showed that household chemical inhalation can cause severe respiratory failure. Following the withdrawal of humidifier disinfectants from the Korean market in 2012, no such cases were reported. This tragic event is a warning that appropriate safety regulations and monitoring for potential toxic household chemicals are critical to protect public health.
Adult* ; Animals ; Case-Control Studies ; Centers for Disease Control and Prevention (U.S.) ; Disinfectants* ; Family Characteristics ; Humans ; Humidifiers* ; Inhalation* ; Korea ; Lung Injury* ; Lung* ; Peripartum Period ; Public Health ; Respiratory Insufficiency ; Social Control, Formal

PURPOSE: Oxidative stress during CO2 pneumoperitoneum is reported to be associated with decreased bioactivity of nitric oxide (NO). However, the changes in endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), and arginase during CO2 pneumoperitoneum have not been elucidated. MATERIALS AND METHODS: Thirty male Sprague-Dawley rats were randomized into three groups. After anesthesia induction, the abdominal cavities of the rats of groups intra-abdominal pressure (IAP)-10 and IAP-20 were insufflated with CO2 at pressures of 10 mm Hg and 20 mm Hg, respectively, for 2 hours. The rats of group IAP-0 were not insufflated. After deflation, plasma NO was measured, while protein expression levels and activity of eNOS, iNOS, arginase (Arg) I, and Arg II were analyzed with aorta and lung tissue samples. RESULTS: Plasma nitrite concentration and eNOS expression were significantly suppressed in groups IAP-10 and IAP-20 compared to IAP-0. While expression of iNOS and Arg I were comparable between the three groups, Arg II expression was significantly greater in group IAP-20 than in group IAP-0. Activity of eNOS was significantly lower in groups IAP-10 and IAP-20 than in group IAP-0, while iNOS activity was significantly greater in group IAP-20 than in groups IAP-0 and IAP-10. Arginase activity was significantly greater in group IAP-20 than in groups IAP-0 and IAP-10. CONCLUSION: The activity of eNOS decreases during CO2 pneumoperitoneum, while iNOS activity is significantly increased, a change that contributes to increased oxidative stress and inflammation. Moreover, arginase expression and activity is increased during CO2 pneumoperitoneum, which seems to act inversely to the NO system.
Animals ; Aorta/*physiology ; Arginase/*antagonists & inhibitors ; Enzyme Inhibitors/administration & dosage/pharmacology ; Inflammation/etiology/*prevention & control ; Injections, Subcutaneous ; Lung Injury/etiology/prevention & control ; Male ; Nitric Oxide/metabolism ; Nitric Oxide Synthase Type II/*metabolism ; Nitric Oxide Synthase Type III/*metabolism ; Oxidative Stress/*drug effects ; Pneumoperitoneum/*complications/drug therapy ; Rats ; Rats, Sprague-Dawley