Alveolar Wall Thickness Research Articles

A novel minimal invasive mouse model of extracorporeal circulation.

Extracorporeal circulation (ECC) is necessary for conventional cardiac surgery and life support, but it often triggers systemic inflammation that can significantly damage tissue. Studies of ECC have been limited to large animals because of the complexity of the surgical procedures involved, which has hampered detailed understanding of ECC-induced injury. Here we describe a minimally invasive mouse model of ECC that may allow more extensive mechanistic studies. The right carotid artery and external jugular vein of anesthetized adult male C57BL/6 mice were cannulated to allow blood flow through a 1/32-inch external tube. All animals (n = 20) survived 30 min ECC and subsequent 60 min observation. Blood analysis after ECC showed significant increases in levels of tumor necrosis factor α, interleukin-6, and neutrophil elastase in plasma, lung, and renal tissues, as well as increases in plasma creatinine and cystatin C and decreases in the oxygenation index. Histopathology showed that ECC induced the expected lung inflammation, which included alveolar congestion, hemorrhage, neutrophil infiltration, and alveolar wall thickening; in renal tissue, ECC induced intracytoplasmic vacuolization, acute tubular necrosis, and epithelial swelling. Our results suggest that this novel, minimally invasive mouse model can recapitulate many of the clinical features of ECC-induced systemic inflammatory response and organ injury.

Alcohol potentiates postburn remote organ damage through shifts in fluid compartments mediated by bradykinin.

Of the 450,000 burn patients each year, 50% have a positive blood alcohol content, and this predisposes them to worsened clinical outcomes. Despite high prevalence and established consequences, the mechanisms responsible for alcohol-mediated complications of postburn remote organ damage are currently unknown. To this end, mice received a single dose of alcohol (1.12 g/kg) or water by oral gavage and were subjected to a 15% total body surface area burn. Animals with a burn alone lost ∼5% of their body weight in 24 h, whereas intoxicated and burned mice lost only 1% body weight (P < 0.05) despite a 17% increase in hematocrit (P < 0.05) and a 57% increase in serum creatinine (P < 0.05) over burn injury alone. This retention of water weight despite increased dehydration suggests that intoxication at the time of a burn causes a shift in fluid compartments that may exacerbate end-organ ischemia and damage as evidenced by a 3-fold increase in intestinal bacterial translocation (P < 0.05), a 30% increase (P < 0.05) in liver weight-to-body weight ratio, and an increase in alveolar wall thickness over a burn alone. Furthermore, administration of the bradykinin antagonist HOE140 30 min after intoxication and burn restored fluid balance and alleviated end-organ damage. These findings suggest that alcohol potentiates postburn remote organ damage through shifts in fluid compartments mediated by bradykinin.

Quercetin protects against lipopolysaccharide-induced acute lung injury in rats through suppression of inflammation and oxidative stress.

IntroductionAcute lung injury (ALI) is an acute inflammatory disease characterized by excess production of inflammatory factors in lung tissue. Quercetin, a herbal flavonoid, exhibits anti-inflammatory and anti-oxidative properties. This study was performed to assess the effects of quercetin on lipopolysaccharide (LPS)-induced ALI.Material and methodsSprague-Dawley rats were randomly divided into 3 groups: the control group (saline alone), the LPS group challenged with LPS (Escherichia coli 026:B6; 100 µg/kg), and the quercetin group pretreated with quercetin (50 mg/kg, by gavage) 1 h before LPS challenge. Bronchoalveolar lavage fluid (BALF) samples and lung tissues were collected 6 h after LPS administration. Histopathological and biochemical parameters were measured.ResultsThe LPS treatment led to increased alveolar wall thickening and cellular infiltration in the lung, which was markedly prevented by quercetin pretreatment. Moreover, quercetin significantly (p < 0.05) attenuated the increase in the BALF protein level and neutrophil count and lung wet/dry weight ratio and myeloperoxidase activity in LPS-challenged rats. The LPS exposure evoked a 4- to 5-fold rise in BALF levels of tumor necrosis factor-α and interleukin-6, which was significantly (p < 0.05) counteracted by quercetin pretreatment. Additionally, quercetin significantly (p < 0.05) suppressed the malondialdehyde level and increased the activities of superoxide dismutase, catalase, and glutathione peroxidase in the lung of LPS-treated rats.ConclusionsQuercetin pretreatment effectively ameliorates LPS-induced ALI, largely through suppression of inflammation and oxidative stress, and may thus have therapeutic potential in the prevention of this disease.

Effect of captopril on serum TNF-α level in acute lung injury rats induced by HCL.

To observe the effect of captopril on the tumor necrosis factor-α (TNF-α) level and arterial blood gases in acute lung injury (ALI) induced by HCL in rats, and to analyze its protective mechanism. Fifty Wistar rats were selected and randomly divided into three groups, with 20 rats in Group I and II, respectively and 10 animals in Group III. ALI model was constructed by intratracheal injection of diluted hydrochloric acid (pH=1.25, 1.2 mL/kg). Group I rats received not any treatment after construction of ALI model. Group II rats were treated with captopril (5 mg/kg, i.p.) 5 min after induction of ALI. Group III served as normal control without any treatment. Ninety minutes after construction of ALI model, all the rats were sacrificed. Blood was withdrawn for detection of TNF-α level and arterial blood gases index. And lung tissue slices of the three groups were prepared for observation of pathologic histology changes. TNF-α level in serum of Group I and II rats was significantly higher than that in Group III (P<0.05), while TNF-α level in serum of Group II was significantly lower in Group I (P<0.05). PaCO2 level was significantly higher (P<0.05), while PaO2 was significantly lower (P<0.05) in Group I and II rats than those in Group III. PaCO2 was significantly lower (P<0.05) and PaO2 was significantly higher (P<0.05) in Group II than those in Group I. Histological observation showed diffuse congestion and severe edema of lung tissue, obvious thickening and structure damage of alveolar walls and a large amount of neutrophil infiltration in Group I rats. Group II rats showed mild edema of lung tissue; only a small portion of alveolar walls showed thickening and only a few of neutrophil infiltration could be observed. The degree of injury was remarkably slighter than that of Group I rats. Group III rats showed clear lung tissue structure and normal morphology; alveolar walls were uniform and the margin was smooth and few neutrophil could be observed. Captopril can significantly reduce serum TNF-α level, elevate PaO2 and reduce PaCO2 in rats with ALI. It has a protective effect on ALI rats.

Intervention mechanisms of mesenchymal stem cells in juvenile mice model of acute lung injury induced by lipopolysaccharide

Objective To explore the changes in expression levels of nuclear factor (NF)-κB, tumor necrosis factor (TNF)-α in the lungs of juvenile mice with acute lung injury (ALI) induced by lipopolysaccharide (LPS). And observe the repair of lung damage after intervening with exogenous mesenchymal stem cells (MSCs). Methods Thirty male juvenile C57 mice were randomly divided into the control group, the ALI group, and the ALI+ MSCs group by the random number table method. Mice from each group were euthanized at 12 h and 48 h. The ALI model of juvenile mice was established by intraperitoneal injection of LPS 10 mg/kg. MSCs from mice bone marrow were isolated, cultured and amplified in vitro, and the MSCs (1×106/ml) 0.1 ml were given to mice via caudal vein. MSCs marker were identificated by flow cytometry. Pathomorphological changes of mice lung were observed under light microscope after Hematoxylin-Eosin staining. The protein expression changes of NF-κB, TNF-α were observed using immunohistochemistry. Results Compared with the control group, the protein expression levels of NF-κB, TNF-α were significantly higher at 12 h and 48 h in the lungs of the ALI group (P<0.05). While those in ALI + MSCs group were markedly lower at these time points than the ALI group[NF-κB: 12 h: (0.181±0.008) OD vs (0.203±0.008) OD, 48 h: (0.197±0.002) OD vs (0.210±0.005) OD; TNF-α: 12 h: (0.185±0.004) OD vs (0.201±0.011) OD, 48 h: (0.185±0.002) OD vs (0.215±0.009) OD] (P<0.05). Histopathological evalution showed that typical pathological inflammation lesions in the lung were observed in ALI group, including alveolar congestion, hemorrhage, edema, infiltration of neutrophils in the airspace or vessel wall, thickness of the alveolar wall; pathological changes were relieved obviously in ALI+ MSCs group. Conclusion The expression of NF-κB and TNF-α are increased in lung tissues in the juvenile mice model of ALI induced by LPS. MSCs can alleviate injury degree of ALI induced by LPS in mice, the mechanism of action may correlate with decreasing NF-κB and TNF-α content in lung tissue. Key words: Acute lung injury; Mesenchymal stem cells; Nuclear factor-κB; Tumor necrosis factor-α; Mice

Flow-controlled expiration: a novel ventilation mode to attenuate experimental porcine lung injury

Whereas the effects of various inspiratory ventilatory modifications in lung injury have extensively been studied, those of expiratory ventilatory modifications are less well known. We hypothesized that the newly developed flow-controlled expiration (FLEX) mode provides a means of attenuating experimental lung injury. Experimental acute respiratory distress syndrome was induced by i.v. injection of oleic acid in 15 anaesthetized and mechanically ventilated pigs. After established lung injury ([Formula: see text]ratio <27 kPa), animals were randomized to either a control group receiving volume-controlled ventilation (VCV) or a treatment group receiving VCV with additional FLEX (VCV+FLEX). At predefined times, lung mechanics and oxygenation were assessed. At the end of the experiment, the pigs were killed, and bronchoalveolar fluid and lung biopsies were taken. Expression of inflammatory cytokines was analysed in lung tissue and bronchoalveolar fluid. Lung injury score was determined on the basis of stained tissue samples. Compared with the control group (VCV; n=8), the VCV+FLEX group (n=7) demonstrated greater dynamic lung compliance and required less PEEP at comparable [Formula: see text] (both P<0.05), had lower regional lung wet-to-dry ratios and lung injury scores (both P<0.001), and showed less thickening of alveolar walls (an indicator of interstitial oedema) and de novo migration of macrophages into lung tissue (both P<0.001). The newly developed FLEX mode is able to attenuate experimental lung injury. FLEX could provide a novel means of lung-protective ventilation.

Edaravone injected at the start of reperfusion suppresses myonephropathic metabolic syndrome in rats.

The purpose of this study was to evaluate whether edaravone (Radicut(®), Mitsubishi Tanabe Pharma Co., Osaka, Japan) injected at the start of reperfusion can suppress myonephropathic-metabolic syndrome (MNMS). MNMS models were made by clamping the bilateral common femoral arteries for 5 hours. At de-clamping (at the start of reperfusion), they were intra-peritoneal injected with 9.0 mg/kg of edaravone (the edaravone group, n = 5) or an equal volume of saline (the control group, n = 5). At five hours after de-clamping, the lower extremity muscles were stained with hematoxylin & eosin (H&E) to count the viable cells, and periodic acid- Schiff (PAS) to assess the glycogen storage. The lungs were also stained with H&E to expresse the alveolar wall thickness, and naphthol AS-D chloroacetate esterase to label infiltrating active neutrophils. The viable muscle cells in the edaravone group was significantly greater than that of the control group (593 ± 60 vs. 258 ± 31 cells/mm(2), p < 0.01). The PAS-positive area in the edaravone group was also significantly higher than that in the control group (30.1 ± 6.9 vs. 7.3 ± 2.1%, p < 0.001). The alveolar wall thickness in the edaravone group was significantly lower than that in the control group (63.6 ± 5.6 vs. 17.2 ± 5.2%, p < 0.001). The active neutrophil infiltration in the edaravone group was also significantly lower than that in the control group (249 ± 59 vs. 68 ± 8 cells/mm(2), p < 0.001). We conclude that edaravone injected at the start of reperfusion can suppress not only muscle reperfusion injury but also lung damage.

Prevention of pulmonary fibrosis with salvianolic acid A by inducing fibroblast cell cycle arrest and promoting apoptosis

Ethnopharmacological relevanceDanshen (Salvia miltiorrhiza Bunge) is widely used in traditional Chinese medicine (TCM), often in combination with other herbs, to treat a diversity of ailments. More recent studies have focused on its possible roles in the treatment of respiratory diseases (pneumonia and pulmonary fibrosis) and found that it has pharmacological activity that protects pulmonary morphology and function. However, the mechanism underlying this activity has not yet been clarified. Materials and methodsThe purpose of this study was to investigate the anti-pulmonary fibrosis effects exerted by salvianolic acid A (SAA), the ingredient responsible for the pharmacological activity of Danshen, and the underlying mechanisms. Bleomycin (BLM)-induced rat pulmonary fibrosis was used to evaluate the antifibrotic role of SAA, and fibroblast cells were used to study the mechanism involved. ResultsBLM-treated rats exhibited increased alveolar wall thickness and collagen deposition in lung tissues, but these pathologies were greatly attenuated by daily administration of SAA. We also found that SAA significantly inhibited the proliferation, adhesion and migration of fibroblasts in vitro. This was partly due to a strong induction of cell cycle arrest and apoptosis upon SAA treatment. Consistent with these phenotypes, we observed decreased expression of the cell cycle-related proteins cyclin D1, cyclin E1, and cyclin B1, and increased expression of p53 and p21 in SAA-treated cells. In addition, the anti-apoptotic Bcl-2 protein decreased in a dose-dependent manner, while cleaved caspase-3 protein increased upon SAA treatment. ConclusionsThese results suggest that the alleviation of rat pulmonary fibrosis by SAA is due to the inhibition of fibroblast proliferation and induction of apoptosis, which occurs mainly through p53-dependent growth arrest and apoptosis. We suggest that SAA should be considered as a potential novel therapeutic agent for the treatment of fibrotic lung diseases.

Preventive effect of chrysin on bleomycin-induced lung fibrosis in rats.

The aim of the current study is determination of protective effect of chrysin (CRS), a natural flavonoid, on cell injury produced by lung fibrosis induced with bleomycin (BLC) in rats. Twenty-eight female rats were assigned to four groups as follows: control group, CRS group; 50 mg/kg CRS was continued orally for 14 days, BLC group; a single intratracheal injection of BLC (2.5 mg/kg body weight in 0.25 ml phosphate buffered saline), BLC + CRS group; 50 mg/kg CRS was administered 1 day before the intratracheal BLC injection and continued for 14 days orally. All animals were sacrificed at day 14th after BLC administration. The semiquantitative assessment of histopathological consisting of lung inflammation and collagen deposition, tissue levels of thiobarbituric acid reactive substances (TBARS), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), reducted glutathione (GSH) were measured. BLC provoked histological changes consisting of alveolar congestion, increase connective tissue, infiltration, and the thickness of alveolar wall were detected significantly when compared to the control group (p ≤ 0.0001). CRS supplementation significantly restored these histological damages (p ≤ 0.0001). The level of tissue TBARS was increased with BLC (p < 0.01). Increased level of TBARS was significantly reversed by CRS administration. Also, BLC administration reduced tissue activities of SOD, GPx, CAT, and GSH in the lung tissue compared to control group (p < 0.01). Furthermore, the reduction in activities of CAT, SOD, and level of GSH were prevented by CRS supplementation (p < 0.01). In this study, we demonstrated for the first time that CRS significantly prevents BLC-induced lung inflammation and fibrosis in rats. Further studies are needed to assess the role of CRS in the treatment of lung inflammation and fibrosis.

Comparative study of ex vivo probe‐based confocal laser endomicroscopy and light microscopy in lung cancer diagnostics

Probe-based confocal laser endoscopy (pCLE) allows for real-time non-invasive histological imaging via bronchoscopy. Interpreting CLE images and correlating with traditional histopathology remains challenging. We performed an ex vivo study to evaluate the correlation between light microscopy findings and pCLE imaging of primary lung carcinoma. Post-lobectomy specimens for lung cancer nodules were examined ex vivo by pCLE. The examined areas were marked with brilliant green dye, and the surrounding tissues were stained by methylene blue dye. Lung tissue segments were resected and histopathological specimens were generated with 50-μm thickness from the marked areas and stained with haematoxylin and eosin. Pathologists and pulmonologists reviewed the images for correlating features. Eighteen lobectomy specimens from 18 different patients were collected. Three primary features were observed in all samples using pCLE in the cancer surroundings: alveolar dystelectasis with thickening of alveolar walls, alveolar edema and a large amount of macrophages. The stromal and parenchymal components of the studied subtypes of non-small-cell lung cancer differed from each other. The stromal component for all nine adenocarcinoma specimens had a highly fluorescent field penetrated by dark hollows. All six squamous cell carcinoma specimens had the stromal component appeared as 'biparously' branching, highly fluorescent fibres. No stromal component was observed in any small-cell carcinoma specimen, and at low power field, the cellular component was dominant with an observed light scattering pattern. pCLE can identify lung carcinoma in ex vivo samples. Certain light microscopy features of lung carcinoma can be visualized with pCLE.

A human monoclonal anti-TNF alpha antibody (adalimumab) reduces airway inflammation and ameliorates lung histology in a murine model of acute asthma

BackgroundA few experimental studies related to asthma have unveiled the beneficial effects of TNF alpha blocking agents on the airway histology, cytokine levels in bronchoalveolar lavage and bronchial hyper-responsiveness. In the current study, we aimed to assess the effect of adalimumab on the inflammation and histology of asthma in a murine model. MethodTwelve-week-old BALB/c (H-2d/d) female rats (n=18) were allocated into three groups, including (group I) control (phosphate-buffered saline was implemented), (group II) asthma induced with OVA (n=6), and (group III) asthma induced with OVA+treated with adalimumab (n=6). Rats were executed on the 28th day of the study. The lung samples were fixed in 10% neutral buffered formalin. Lung parenchyma, alveolus, peribronchial and perivascular inflammation were assessed. Lung pathological scoring was performed. ResultSeverity of lung damage was found to be reduced significantly in the asthma induced with OVA+treated with adalimumab group. When compared with the untreated group, adalimumab significantly reduced the inflammatory cells around the bronchi and bronchioles, and reduced inflammation of the alveolar wall and alveolar wall thickness as well (median score=1, p=0.52). Peribronchial smooth muscle hypertrophy and oedema were significantly reduced after adalimumab administration. ConclusionAdalimumab (a human monoclonal anti-TNF alpha antibody) therapy significantly reduced the severity of lung damage by decreasing cellular infiltration and improvement on the lung histology in a murine model of acute asthma.

Comparative Study between Intravenous and Intraperitoneal Stem Cell Therapy in Amiodarone Induced Lung Injury in Rat.

Background and Objectives:The fibrosing form of lung injury (occupational, environmental, infective or drug induced) is associated with significant morbidity and mortality. Amiodarone (AM), often prescribed for control of arrhythmias is considered a potential cause. No effective treatment was confirmed, except lung transplantation. Intravenous (IV) stem cell therapy may produce pulmonary emboli or infarctions. Despite being commonly used in clinical practice, the intraperitoneal (IP.) route has been rarely used for cell delivery. The present study aimed at investigating and comparing the possible effect of IP stem cell therapy (SCT) on pulmonary toxicity versus the intravenous route in a rat model of amiodarone induced lung damage.Methods and Results:36 adult male albino rats were divided into 4 groups. Rats of AM group were given 30 mg/kg daily orally for 4 weeks. Rats of IV SCT group were injected with stem cells in the tail vein. Rats of IP SCT group received IP cell therapy. Histological, histochemical, immunohistochemical and morphometric studies were performed. Obstructed bronchioles, overdistended alveoli, reduced type I pneumocytes, increased thickness of alveolar septa and vessels wall besides increased area% of collagen fibers regressed in response to IV and IP SCT. The improvement was more obvious in IV group. The area% of Prussion blue +ve and CD105 +ve cells was significantly higher in IV group.Conclusions:Cord blood MSC therapy proved definite amelioration of lung injury ending in fibrosis. The effect of IP SCT was slightly inferior to that of IV SCT, which may be overwhelmed by repeated IP injection.

The Idiopathic Interstitial Pneumonias: Histology and Imaging

Introduction The idiopathic interstitial pneumonias (IIPs) are a subgroup of diffuse parenchymal lung diseases (DPLDs), the latter of which also includes DPLD of known causes, such as drugs, or association, such as collagen vascular disease; granulomatous DPLD, such as sarcoidosis; and other distinct forms of DPLD, such as lymphangioleiomyomatosis and pulmonary Langerhans cell histiocytosis. In the revised American Thoracic Society/European Respiratory Society Classification of the Idiopathic Interstitial Pneumonias, the IIPs are grouped as follows: (1) chronic fibrosing (idiopathic pulmonary fibrosis [IPF] and idiopathic nonspecific interstitial pneumonia [NSIP]); (2) smoking related (respiratory bronchiolitisinterstitial lung disease and desquamative interstitial pneumonia); and (3) acute or subacute (acute interstitial pneumonia [AIP] and cryptogenic organizing pneumonia [COP]). The idiopathic interstitial pneumonias are a heterogeneous group of nonneoplastic disorders of unknown etiology—“idiopathic,” characterized by variable inflammation and fibrosis of the lung parenchyma—“interstitial pneumonia.” There are commonalities in this seemingly disparate group. Firstly, patients present with dyspnea, decreasing lung volumes, and normal flow rates. Secondly, open lung biopsy demonstrates variable alveolar wall thickening and inflammation, which can be difficult for pathologists to classify because of the variability.

Mammalian pathogenesis of oseltamivir-resistant pandemic (H1N1) 2009 influenza virus isolated in South Korea

Oseltamivir, a neuraminidase (NA) inhibitor, has been widely used for the treatment of patients infected with the pandemic (H1N1) 2009 influenza virus. With the increasing use of oseltamivir, drug-resistant mutants emerged rapidly and 11 cases of resistant viruses were detected during the 2009 H1N1 pandemic in South Korea. To better understand the differences between oseltamivir-susceptible and oseltamivir-resistant virus, we compared the replication and pathogenesis of the NA H275Y mutant virus, A/Gyeongnam/1820/2009, in ferrets and mice with those of oseltamivir-susceptible A/Korea/01/2009 virus. Oseltamivir-resistant virus infected ferrets showed mild clinical signs and the virus replicated well in the upper respiratory tract and slightly in the lower respiratory tract. No virus was detected in the extrapulmonary organs. Severe bronchopneumonia and thickening of alveolar walls were detected in the lungs. Viral antigens were detected mainly in the bronchiolar epithelial cells, cells present in the interstitial septa, pneumocytes and peribronchial glands with severe peribronchitis. A/Gyeongnam/1820/2009 virus-infected mice showed weight loss and the virus replicated in lungs with high titer. Histopathologically, the mice showed mild to moderate alveolitis, interstitial pneumonia and perivascular lymphoid tissue hyperplasia. In lungs, bronchiolar epithelial cells, pneumocytes and interstitial inflammatory cells were infected by influenza virus and trachea epithelial cells were the sites of infection.When compared with the results of A/Korea/01/2009 oseltamivir-susceptible pandemic influenza virus, an oseltamivir-resistant virus isolated in South Korea showed fewer pathogenic properties in ferrets and similar fitness in mice.

Expression Level and Subcellular Localization of Heme Oxygenase-1 Modulates Its Cytoprotective Properties in Response to Lung Injury: A Mouse Model

Premature infants exposed to hyperoxia suffer acute and long-term pulmonary consequences. Nevertheless, neonates survive hyperoxia better than adults. The factors contributing to neonatal hyperoxic tolerance are not fully elucidated. In contrast to adults, heme oxygenase (HO)-1, an endoplasmic reticulum (ER)-anchored protein, is abundant in the neonatal lung but is not inducible in response to hyperoxia. The latter may be important, because very high levels of HO-1 overexpression are associated with significant oxygen cytotoxicity in vitro. Also, in contrast to adults, HO-1 localizes to the nucleus in neonatal mice exposed to hyperoxia. To understand the mechanisms by which HO-1 expression levels and subcellular localization contribute to hyperoxic tolerance in neonates, lung-specific transgenic mice expressing high or low levels of full-length HO-1 (cytoplasmic, HO-1-FL(H) or HO-1-FL(L)) or C-terminally truncated HO-1 (nuclear, Nuc-HO-1-TR) were generated. In HO-1-FL(L), the lungs had a normal alveolar appearance and lesser oxidative damage after hyperoxic exposure. In contrast, in HO-1-FL(H), alveolar wall thickness with type II cell hyperproliferation was observed as well worsened pulmonary function and evidence of abnormal lung cell hyperproliferation in recovery from hyperoxia. In Nuc-HO-1-TR, the lungs had increased DNA oxidative damage, increased poly (ADP-ribose) polymerase (PARP) protein expression, and reduced poly (ADP-ribose) (PAR) hydrolysis as well as reduced pulmonary function in recovery from hyperoxia. These data indicate that low cytoplasmic HO-1 levels protect against hyperoxia-induced lung injury by attenuating oxidative stress, whereas high cytoplasmic HO-1 levels worsen lung injury by increasing proliferation and decreasing apoptosis of alveolar type II cells. Enhanced lung nuclear HO-1 levels impaired recovery from hyperoxic lung injury by disabling PAR-dependent regulation of DNA repair. Lastly both high cytoplasmic and nuclear expression of HO-1 predisposed to long-term abnormal lung cellular proliferation. To maximize HO-1 cytoprotective effects, therapeutic strategies must account for the specific effects of its subcellular localization and expression levels.

Systemic hydrogen sulfide administration partially restores normal alveolarization in an experimental animal model of bronchopulmonary dysplasia

Arrested alveolarization is the pathological hallmark of bronchopulmonary dysplasia (BPD), a complication of premature birth. Here, the impact of systemic application of hydrogen sulfide (H2S) on postnatal alveolarization was assessed in a mouse BPD model. Exposure of newborn mice to 85% O2 for 10 days reduced the total lung alveoli number by 56% and increased alveolar septal wall thickness by 29%, as assessed by state-of-the-art stereological analysis. Systemic application of H2S via the slow-release H2S donor GYY4137 for 10 days resulted in pronounced improvement in lung alveolarization in pups breathing 85% O2, compared with vehicle-treated littermates. Although without impact on lung oxidative status, systemic H2S blunted leukocyte infiltration into alveolar air spaces provoked by hyperoxia, and restored normal lung interleukin 10 levels that were otherwise depressed by 85% O2. Treatment of primary mouse alveolar type II (ATII) cells with the rapid-release H2S donor NaHS had no impact on cell viability; however, NaHS promoted ATII cell migration. Although exposure of ATII cells to 85% O2 caused dramatic changes in mRNA expression, exposure to either GYY4137 or NaHS had no impact on ATII cell mRNA expression, as assessed by microarray, suggesting that the effects observed were independent of changes in gene expression. The impact of NaHS on ATII cell migration was attenuated by glibenclamide, implicating ion channels, and was accompanied by activation of Akt, hinting at two possible mechanisms of H2S action. These data support further investigation of H2S as a candidate interventional strategy to limit the arrested alveolarization associated with BPD.

Comparison of reducing effect on lung injury of dexamethasone and bosentan in acute lung injury: an experimental study

Background: Different medical therapies are employed in acute lung injury (ALI) but there is still a debate about the efficacy of these drugs. Among these therapies steroids are clinically applied and bosentan is experimentally studied. The aim of this study was to evaluate the efficacy of these two drugs to treat inflammation in ALI by histopathological comparison. Methods: The five experimental groups (n = 5 per group) were: saline control (Group I); lipopolysaccharide (LPS) + saline (Group II); LPS + dexamethasone (Group III); LPS + 50 mg/kg bosentan (Group IV); and LPS + 100 mg/kg bosentan (Group V). Bosentan was administered orally one hour before and 12 hours after LPS treatment. Dexamethasone was administered intraperitoneally in three doses of 1 mg/kg; one dose was co-administered with LPS and the other two doses were given respectively 30 minutes before and after LPS treatment. Vasodilation-congestion, hemorrhage, polymorphonuclear leukocyte (PMN) infiltration, mononuclear leukocyte (MNL) infiltration, alveolar wall thickening, alveolar destruction/emphysematous appearance, and focal organization were the parameters used as criteria for evaluating inflammation and efficacy of treatment. Results: Compared to the LPS-only group (Group II), dexamethasone treatment (Group III) resulted in significant improvements in vasodilation-congestion, hemorrhage, PMN and MNL infiltration, alveolar wall thickening and emphysematous areas. Treatment with 50 mg/kg dose of bosentan (Group IV) also resulted in significant improvements in hemorrhage, PMN and MNL infiltration, alveolar wall thickening and alveolar destruction. Reducing lung injury and reparative effects of 100 mg/kg bosentan were significant in all parameters. Conclusions: Bosentan is as effective as dexamethasone for treating lung injury in ALI. Bosentan at 100 mg/kg can be recommended as a first treatment choice based on its significant reducing lung injury and reparative effects.

Comparison of reducing effect on lung injury of dexamethasone and bosentan in acute lung injury: an experimental study

BackgroundDifferent medical therapies are employed in acute lung injury (ALI) but there is still a debate about the efficacy of these drugs. Among these therapies steroids are clinically applied and bosentan is experimentally studied. The aim of this study was to evaluate the efficacy of these two drugs to treat inflammation in ALI by histopathological comparison.MethodsThe five experimental groups (n = 5 per group) were: saline control (Group I); lipopolysaccharide (LPS) + saline (Group II); LPS + dexamethasone (Group III); LPS + 50 mg/kg bosentan (Group IV); and LPS + 100 mg/kg bosentan (Group V). Bosentan was administered orally one hour before and 12 hours after LPS treatment. Dexamethasone was administered intraperitoneally in three doses of 1 mg/kg; one dose was co-administered with LPS and the other two doses were given respectively 30 minutes before and after LPS treatment. Vasodilation-congestion, hemorrhage, polymorphonuclear leukocyte (PMN) infiltration, mononuclear leukocyte (MNL) infiltration, alveolar wall thickening, alveolar destruction/emphysematous appearance, and focal organization were the parameters used as criteria for evaluating inflammation and efficacy of treatment.ResultsCompared to the LPS-only group (Group II), dexamethasone treatment (Group III) resulted in significant improvements in vasodilation-congestion, hemorrhage, PMN and MNL infiltration, alveolar wall thickening and emphysematous areas. Treatment with 50 mg/kg dose of bosentan (Group IV) also resulted in significant improvements in hemorrhage, PMN and MNL infiltration, alveolar wall thickening and alveolar destruction. Reducing lung injury and reparative effects of 100 mg/kg bosentan were significant in all parameters.ConclusionsBosentan is as effective as dexamethasone for treating lung injury in ALI. Bosentan at 100 mg/kg can be recommended as a first treatment choice based on its significant reducing lung injury and reparative effects.

17β-Estradiol Replacement Reverses Age-Related Lung Disease in Estrogen-Deficient C57BL/6J Mice

The role that estrogens play in the aging lung is poorly understood. Remodeling of the aging lung with thickening of the alveolar walls and reduction in the number of peripheral airways is well recognized. The present study was designed to address whether estrogen deficiency would affect age-associated changes in the lungs of female C57BL/6J mice. Lungs isolated from old mice (24 months old, estrogen-deficient) demonstrated decreased lung volume and decreased alveolar surface area. There was no difference in alveolar number in the lungs of old and young mice (6 months old, estrogen-replete). Estrogen replacement restored lung volume, alveolar surface area, and alveolar wall thickness to that of a young mouse. Estrogen receptor-α (ERα) protein expression increased without a change in ERβ protein expression in the lung tissue isolated from old mice. In the lungs of old mice, the number of apoptotic cells was increased as well as the activation of matrix metalloproteinase-2 and ERK. Young mice had the highest serum 17β-estradiol levels that decreased with age. Our data suggest that in the aging female mouse lung, estrogen deficiency and an increase of ERα expression lead to the development of an emphysematous phenotype. Estrogen replacement partially prevents these age-associated changes in the lung architecture by restoration of interalveolar septa. Understanding the role of estrogens in the remodeling of the lung during aging may facilitate interventions and therapies for aging-related lung disease in women.

Theoretical Calculation of Bending Stiffness of Alveolar Wall

The bending stiffness of the alveolar wall is theoretically analyzed in this study through analytical modeling. First, the alveolar wall facet and its characteristics were geometrically simplified and then modeled using known physical laws. Bending stiffness is shown to be dependent on alveolar wall thickness, density, Poisson's ratio and speed of the longitudinal wave. The normal bending stiffness of the alveolar wall was further determined. For the adult human, the normal bending stiffness is calculated to be 71.0-414.7 nNm, while for the adult mouse it is 1.9-30.0 nNm. The results of this study can be used as a reference for future pulmonary emphysema and fibrosis studies, as the bending stiffness of alveolar wall will be lower and higher, respectively; than the theoretically determined normal values.