Lung Tissue Myeloperoxidase Activity Research Articles

Adenosine diphosphate ribosylation factor 6 inhibition protects burn sepsis induced lung injury through preserving vascular integrity and suppressing ASC inflammasome transmission

BackgroundSevere burns are devastating injuries with significant immune dysfunction and result in substantial mortality and morbidity due to sepsis induced organ failure. Acute lung injury is the most common type of organ injury in sepsis, however, the mechanisms of which are poorly understood and effective therapeutic measures are limited. This study is aimed to investigate the effect of a small Guanosine triphosphatase (GTPase), Adenosine diphosphate ribosylation factor 6 (ARF6), on burn sepsis induced lung injury, and discuss the possible mechanisms. MethodsBurn sepsis was established in male C57BL/6 mice. Mice were anesthetised by intramuscular injection of ketamine and xylazine hydrochloride, then 30% TBSA full thickness burn followed by sub-eschar injection of lipopolysaccharide. Animals were treated with intraperitoneal injection of a small molecule inhibitor of ARF6: NAV-2729, or vehicle, right after the burn and sepsis stimuli were inflicted. Lung tissues were harvested for histopathological observation and the acute lung injury scores were calculated. Organ permeability, Vascular Endothelial Cadherin (VE-cadherin) expression, inflammatory cytokine levels and myeloperoxidase activity in lung tissues were detected. Rat pulmonary microvascular endothelial cells (PMVECs) were stimulated by burn sepsis serum with or without 10 μM NAV-2729. The ARF6 activation, VE-cadherin expression, inflammasome activity, adapter protein apoptosis speck-like protein containing a caspase recruiting domain (ASC) specks and cytokines secretion were determined. Student’s t test was used for comparison between two groups. Multiple comparisons among groups were performed by using analysis of variance, with Tukey’s test for the post hoc test. ResultsNAV-2729 treatment attenuated burn sepsis induced lung injury and promoted survival of burn septic mice by preserving VE-cadherin expression in endothelial cell adherent junction and limited vascular hyperpermeability in lung tissues. Moreover, inflammatory cytokine expression and inflammatory injury in lung tissues were alleviated. Mechanistically, NAV-2729 enhanced vascular integrity by inhibiting ARF6 activation and restoring VE-cadherin expression in PMVECs. In addition, NAV-2729 inhibited ARF6-dependent phagocytosis of ASC specks, thus preventing inflammation propagation mediated by cell-to-cell transmission of ASC specks. ConclusionsARF6 inhibition preserved vascular integrity by restoring expression of VE-cadherin and suppressed the spread of inflammation by affecting phagocytosis of ASC specks, thus protected against sepsis induced lung injury and improve survival of burn septic animals. The findings of this study implied potential therapeutics by which ARF6 inhibition can protect lung function from septic induced lung injury and improve outcomes in burn sepsis.

Liraglutide pretreatment attenuates sepsis-induced acute lung injury.

There are no effective targeted therapies to treat acute respiratory distress syndrome (ARDS). Recently, the commonly used diabetes and obesity medications, glucagon-like peptide-1 (GLP-1) receptor agonists, have been found to have anti-inflammatory properties. We, therefore, hypothesized that liraglutide pretreatment would attenuate murine sepsis-induced acute lung injury (ALI). We used a two-hit model of ALI (sepsis+hyperoxia). Sepsis was induced by intraperitoneal injection of cecal slurry (CS; 2.4 mg/g) or 5% dextrose (control) followed by hyperoxia [HO; fraction of inspired oxygen ([Formula: see text]) = 0.95] or room air (control; [Formula: see text] = 0.21). Mice were pretreated twice daily with subcutaneous injections of liraglutide (0.1 mg/kg) or saline for 3 days before initiation of CS+HO. At 24-h post CS+HO, physiological dysfunction was measured by weight loss, severity of illness score, and survival. Animals were euthanized, and bronchoalveolar lavage (BAL) fluid, lung, and spleen tissues were collected. Bacterial burden was assessed in the lung and spleen. Lung inflammation was assessed by BAL inflammatory cell numbers, cytokine concentrations, lung tissue myeloperoxidase activity, and cytokine expression. Disruption of the alveolar-capillary barrier was measured by lung wet-to-dry weight ratios, BAL protein, and epithelial injury markers (receptor for advanced glycation end products and sulfated glycosaminoglycans). Histological evidence of lung injury was quantified using a five-point score with four parameters: inflammation, edema, septal thickening, and red blood cells (RBCs) in the alveolar space. Compared with saline treatment, liraglutide improved sepsis-induced physiological dysfunction and reduced lung inflammation, alveolar-capillary barrier disruption, and lung injury. GLP-1 receptor activation may hold promise as a novel treatment strategy for sepsis-induced ARDS. Additional studies are needed to better elucidate its mechanism of action.NEW & NOTEWORTHY In this study, pretreatment with liraglutide, a commonly used diabetes medication and glucagon-like peptide-1 (GLP-1) receptor agonist, attenuated sepsis-induced acute lung injury in a two-hit mouse model (sepsis + hyperoxia). Septic mice who received the drug were less sick, lived longer, and displayed reduced lung inflammation, edema, and injury. These therapeutic effects were not dependent on weight loss. GLP-1 receptor activation may hold promise as a new treatment strategy for sepsis-induced acute respiratory distress syndrome.

Efficacy of CU06-1004 via regulation of inflammation and endothelial permeability in LPS-induced acute lung injury

BackgroundAcute lung injury (ALI) is a life-threatening condition that fundamentally results from inflammation and edema in the lung. There are no effective treatments available for clinical use. Previously, we found that as a leakage blocker CU06-1004 prevents endothelial barrier disruption and enhances endothelial cell survival under inflammatory conditions. In this study, we aimed to elucidate the effect of CU06-1004 in terms of prevention of inflammation and endothelial dysfunction in an ALI mouse model.MethodsAn ALI model was established that included intraperitoneal administration of LPS. Following LPS administration, survival rates and lung wet/dry ratios were assessed. Histological analysis was performed using hematoxylin and eosin staining. Scanning electron microscopy was used to examine alveolar and capillary morphology. Cytokines such as IL-1β, IL-6, and TNF-α were analyzed using an ELISA assay of bronchoalveolar lavage fluid (BALF) and serum. Neutrophil infiltration was observed in BALF using Wright-Giemsa staining, and myeloperoxidase (MPO) activity was assessed. Pulmonary vascular leakage was confirmed using Evans-blue dye, and the expression of junctional proteins was evaluated using immunofluorescent staining. Expression of adhesion molecules was observed using immunofluorescence staining. NF-κB activation was determined using immunohistochemistry and western blot analysis.ResultsSurvival rates and pulmonary edema were ameliorated with CU06-1004 treatment. Administration of CU06-1004 normalized histopathological changes induced by LPS, and alveolar-capillary wall thickening was reduced. Compared with the LPS-challenged group, after CU06-1004 treatment, the infiltration of immune cells was decreased in the BALF, and MPO activity in lung tissue was reduced. Similarly, in the CU06-1004 treatment group, pro-inflammatory cytokines were significantly inhibited in both BALF and serum. Evans-blue leakage was reduced, and the expression of junctional proteins was recovered in the CU06-1004 group. Adhesion molecules were downregulated and NF-κB activation was inhibited after CU06-1004 treatment.ConclusionsThese results suggested that CU06-1004 had a therapeutic effect against LPS-induced ALI via alleviation of the inflammatory response and protection of vascular integrity.

Overexpressing six-transmembrane protein of prostate 2 (STAMP2) alleviates sepsis-induced acute lung injury probably by hindering M1 macrophage polarization via the NF-κB pathway.

Acute lung injury (ALI) is a major cause of death in sepsis patients. The Six-transmembrane protein of prostate 2 (STAMP2) is a key regulator of inflammation, while its role in septic ALI remains unclear. Male C57BL/6 mice were subjected to cecal ligation puncture (CLP) to induce experimental sepsis whereas lipopolysaccharide (LPS)-stimulated RAW 264.7 cells were used as the models of septic ALI in vivo and in vitro, respectively. Overexpression of STAMP2 in mouse lungs and RAW264.7 cells was performed with an adenoviral vector. We measured histological lung injury, lung wet/dry weight (W/D) ratio, and pulmonary myeloperoxidase (MPO) activity to assess lung injury extent. Cell counts in bronchoalveolar lavage fluid (BALF) were measured using Giemsa staining. The concentration of inflammatory factors was detected by enzyme-linked immunosorbent assay. The polarization of macrophages was evaluated by inducible nitric oxide synthase (iNOS) and F4/80 staining. The activation of cell apoptosis and NF-κB pathway was evaluated using Western blot, TUNEL staining, immunofluorescence, and immunohistochemistry. Overexpression of STAMP2 alleviated CLP-induced lung injury of mice with decreased W/D ratio of the lung, and MPO activity in lung tissue. STAMP2 overexpression reduced the lung infiltration of inflammatory cells, and the levels of TNF-a, IL-6, and macrophage chemoattractant protein-1 (MCP-1) in BALF. Overexpressed STAMP2 inhibited macrophage M1 polarization in lung tissues as indicated by F4/80 and iNOS stainings in lung tissue. STAMP2 overexpression inhibited RAW 264.7 cell apoptosis by increasing Bcl-2 and decreasing Bax and cleaved-caspase 3 expression. Besides, STAMP2 overexpression suppressed nuclear factor κB (NF-κB) p65 pathway activation, as evidenced by reduced phosphorylation of IκBα, and phosphorylation and translocation of NF-κB p65. In vitro study further proved that STAMP2 overexpression suppressed the NF-κB pathway (IκBα/p65) in macrophages and decreased macrophage M1 polarization and M1-associated inflammatory factor production (TNF-a, IL-6, and MCP-1). Our study for the first time demonstrated that STAMP2 might be able to reduce inflammation in sepsis-induced ALI by inhibiting macrophage M1 polarization through repressing NF-κB signaling activation.

Isopropyl 3-(3, 4-dihydroxyphenyl)-2-hydroxypropanoate protects lipopolysaccharide-induced acute lung injury in mice by attenuating pyroptosis

Isopropyl 3-(3,4-dihydroxyphenyl)-2-hydroxypropanoate (IDHP) is one of the main bioactive metabolites of the Chinese medicinal herb Danshen, which can be absorbed into blood compounds by oral administration of Compound Danshen dripping pills (CDDPs). Previous study showed that IDHP exerted anti-inflammatory effects by abolishing the secretion of proinflammatory factors stimulated by lipopolysaccharide (LPS). However, the effects of IDHP on LPS-induced acute lung injury (ALI) are not fully understood. In the present study, we observed the effects of IDHP on mortality and lung injury in LPS-treated mice and on LPS-induced THP-1 macrophages. Pretreatment with high dose of IDHP was found to reduce the mortality of ALI mice, significantly improve LPS-induced pathological changes, and reduce protein leakage and inhibited myeloperoxidase (MPO) activity in lung tissue. IDHP also inhibited the release of inflammatory factors in bronchoalveolar lavage fluid (BALF) and lung tissue. Meanwhile, IDHP treatment significantly reduced the expression of active-caspase1, Nlrp3, Asc speck formation, Gsdmd (part of the canonical pyroptosis pathway), caspase4 (part of the non-canonical pyroptosis pathway), therefore decreasing IL-1β, IL-18, and ROS secretion in LPS-stimulated THP-1 macrophages. Moreover, after co-culturing endothelial/epithelial cells with conditioned medium (CM) from LPS-stimulated THP-1 macrophages, we found that the protein levels of occludin and Zonula occludens-1 (Zo-1) were increased in IDHP CM-treated endothelial cells compared to those that were LPS CM-treated. Lactic dehydrogenase (LDH) assay shows that IDHP also alleviated LPS-induced endothelial/epithelial cell injury. These findings indicate that the protective effect of IDHP on LPS-induced lung injury may be partly due to the inhibition of pyroptosis pathways.

MicroRNA-9-5p Is Involved in Lipopolysaccharide-Induced Acute Lung Injury Via the Regulation of Macrophage Polarization.

MicroRNA (miR)-9-5p has been shown to affect lung cancer progression and lung fibrosis, but the efficacy of miR-9-5p in acute lung injury (ALI) remained indefinite. The study was performed to probe the modulating mechanism of miR-9-5p in ALI via regulating macrophage polarization. The ALI mouse model was established and blood samples of ALI patients were obtained. MiR-9-5p levels in ALI mice and ALI patients were detected. Mouse pulmonary macrophages were extracted from bronchoalveolar lavage fluid and polarized into M1 and M2 macrophages. Intervention of miR-9-5p expression was performed to observe the effects on M1 polarization and M2 polarization in lung macrophages, inflammatory factors in BALF, wet/dry weight ratio (W/D) in lung tissues, myeloperoxidase (MPO) activity in lung tissues, and lung tissue lesion condition. MiR-9-5p levels were elevated in the lung tissues of ALI mice and ALI patients. MiR-9-5p silencing could repress lung macrophages in ALI mice polarized toward the M1 phenotype and promoted the polarization toward the M2 phenotype, reduced the lung lesions, the lung water content, and the secretion levels of the pro-inflammatory factors TNF-α, IL-6, and IL-1β in BALF, increased the secretion of the anti-inflammatory factor IL-10, as well as impeded the MPO activity in the lung tissues of ALI mice. MiR-9-5p deletion ameliorates LPS-induced inflammatory infiltration in lung tissues via inhibiting the polarization of mouse lung macrophages to the M1 phenotype and promoting the polarization to the M2 phenotype.

Interleukin-37 ameliorates cigarette smoke-induced lung inflammation in mice

Cigarette smoking (CS) is the leading cause of chronic obstructive pulmonary disease, and its severity is closely related to lung inflammation. Interleukin (IL)-37 is a newly discovered member of the IL-1 family with anti-inflammatory activity. Our study aimed to elucidate the effect of IL-37 on CS-induced lung inflammation in mice. In this study, mice were exposed to six cigarettes for 1 h three times daily (4 h smoke-free intervals) for 10 consecutive days. Mice were treated intranasally with IL-37-expressing lentivirus and empty lentivirus particles 1 day before the first CS or sham exposure. Mice were sacrificed on day 11 to evaluate the effect of IL-37 on CS-induced pulmonary inflammation in mice. Administering IL-37-expressing lentivirus significantly reduced CS-induced weight loss in mice compared to empty lentivirus controls (P < 0.05). Histological analysis showed that IL-37 significantly alleviated inflammatory cell recruitment, alveolar septum enlargement, alveolar wall attenuation, mucus hypersecretion, and goblet cell metaplasia in mouse lungs (P < 0.001). IL-37 expression also significantly inhibited CS-induced increases in inflammatory cells (including lymphocytes, neutrophils, and macrophages) in mouse lungs (P < 0.05), as well as pro-inflammatory cytokines such as IL-1β, IL-6, IL-17, monocyte chemotactic protein-1 and tumor necrosis factor-α production (P < 0.05). IL-37 also significantly reduced myeloperoxidase activity in mouse serum (P < 0.01) and lung tissues (P < 0.001). Therefore, IL-37 can ameliorate CS-induced pulmonary inflammation in mice and IL-37 may be a potential therapeutic strategy for CS-induced lung inflammatory diseases.

Polyphenols-Rich Fraction from Annona muricata Linn. Leaves Attenuates Oxidative and Inflammatory Responses in Neutrophils, Macrophages, and Experimental Lung Injury.

Annona muricata Linn. is a common plant found in the warmest regions of South and Central America and its use in traditional medicine has been reported for the treatment of various illnesses. In the current study, we investigate the antioxidant and anti-inflammatory activities of crude extract and fractions from A. muricata L. leaves in isolated murine phagocytic immune cells as well as experimental LPS-induced acute lung injury (ALI). In a luminol-dependent chemiluminescence assay, we showed that ethyl acetate (EtOAc.f) and n-butanol (BuOH.f) fractions—both rich in polyphenols—reduced the generation of reactive oxygen species (ROS) by neutrophils stimulated with opsonized zymosan; similar results were found in culture of bone marrow-derived macrophages (BMDMs). By evaluating anti-inflammatory activity in BMDMs, EtOAc.f and BuOH.f reduced secretion of IL-6 and expression of the co-stimulatory molecule CD40. Furthermore, in LPS-induced ALI, oral administration of EtOAc.f reduced myeloperoxidase (MPO) activity in lung tissue. In addition, on a mechanism dependent on glutathione levels, the oxidative damage was also attenuated. These findings revealed direct antioxidant and anti-inflammatory activities of polyphenols-rich fractions of A. muricata L. leaves on neutrophils and macrophages. Moreover, the reduced oxidative damage and levels of inflammatory markers in experimental ALI suggest that these fractions might be explored for the development of new therapies for inflammatory conditions.

Physalin B ameliorates inflammatory responses in lipopolysaccharide-induced acute lung injury mice by inhibiting NF-κB and NLRP3 via the activation of the PI3K/Akt pathway

Ethnopharmacological relevancePhysalin B (PB) is an active constituent of Physalis alkekengi L. var. Franchetii, which is a traditional medicine for clearing heat and detoxification, resolving phlegm, and diuresis. It has been commonly applied to treat sore throat, phlegm-heat, cough, dysuria, pemphigus, and eczema. Aim of studyPhysalin B has shown efficacy as an anti-acute lung injury (ALI) agent previously; however, its mechanisms of action remain unclear. In the present study, we established a lipopolysaccharide-induced septic ALI model using BALB/c mice to further confirm the therapeutic potential of PB and to assess the underlying molecular mechanisms. Materials and methodsWe used 75% ethanol and macroporous resin for extraction, separation, and enrichment of PB. The LPS-induced ALI mouse model was used to determine anti-inflammatory effects of PB. The severity of acute lung injury was evaluated by hematoxylin and eosin staining, wet/dry lung ratio, and myeloperoxidase (MPO) activity in lung tissue. An automatic analyzer was used to measure the arterial blood gas index. Protein levels of pro-inflammatory cytokines in serum, bronchoalveolar lavage fluid (BALF), and lung tissue was measured using an ELISA. Quantitative RT-PCR was used to measure changes in RNA levels of pro-inflammatory cytokines in the lungs. A fluorometric assay kit was used for determination of apoptosis-related factors to assess anti-apoptotic effects of PB. Western blotting was used to assess levels of key pathway proteins and apoptosis-related proteins. Connections between the pathways were tested through inhibitor experiments. ResultsPretreatment with PB (15 mg kg-1 d-1, i.g.) significantly reduced lung wet/dry weight ratios and MPO activity in blood and BALF of ALI mice, and it alleviated LPS-induced inflammatory cell infiltration in lung tissue. The levels of pro-inflammatory factors TNF-α, IL-6, and IL-1β and their mRNA levels in blood, BALF, and lung tissue were reduced following PB pretreatment. PB pretreatment also downregulated the apoptotic factors caspase-3, caspase-9, and apoptotic protein Bax, and it upregulated apoptotic protein Bcl-2. The NF-κB and NLRP3 pathways were inhibited through activation of the PI3K/Akt pathway due to PB pretreatment, whereas administration of PI3K inhibitors increased activation of these pathways. ConclusionsTaken together, our results suggest that the anti-ALI properties of PB are closely associated with the inactivation of NF-κB and NLRP3 by altering the PI3K/Akt pathway. Furthermore, our findings provide a novel strategy for application of PB as a potential agent for treating patients with ALI. To the best of our knowledge, this is the first study to elucidate the underlying mechanism of action of PB against ALI.

High concentration of hydrogen gas alleviates Lipopolysaccharide-induced lung injury via activating Nrf2 signaling pathway in mice

Background and aimsThe lung is the first organ to fail in sepsis. Our previous studies have proven that 2% molecular hydrogen (H2) inhalation remain a protective effect on a septic animal model via its anti-inflammatory and anti-apoptosis properties. This current research aims to observe the therapeutic effect of high concentration hydrogen (67%, HCH) on lipopolysaccharide (LPS) induced acute lung injury (ALI), and further investgate the role of Nrf2 signaling pathway. MethodsALI model was induced by LPS areosol inhalation. HCH were treated for 1 h at 1 and 6 h after modelling. Lung tissues and bronchoalveolar lavage fluid (BALF) were collected 4 and 24 h after the exposure of LPS. The histological scores, wet/dry weight ratios, myeloperoxidase (MPO) activity, protein content and cytokine levels in BALF, apoptosis condition of lung cells, expression of Nrf2 and NF-κB were assessed in both wild type and Nrf2-knockout mice. ResultsHCH Inhalation significantly alleviated LPS-induced pathological alterations of lung, and reduced the protein concentration, the wet/dry weight ratio, and the MPO activity of lung tissue. HCH Inhalation improved LPS-induced increasement in caspase-3 activity and the number of TUNEL-positive cells. HCH inhalation attenuated the LPS induced increased total cell content and polymorphonuclear granulocyte content, and pro-inflammatory cytokines, Nrf2 and NF-κB expression. HCH could not produce protective effct in Nrf2-knockout mice. ConclusionHCH can effectively alleviate LPS-induced ALI, which may be related to activation of Nrf2 signaling pathway and inhibition of inflammatory response and cell apoptosis mediated by NF-κB.

Perfluorocarbon-Based Oxygen Carriers and Subnormothermic Lung Machine Perfusion Decrease Production of Pro-Inflammatory Mediators

The quality of marginal donor lungs is clinically assessed with normothermic machine perfusion. Although subnormothermic temperature and perfluorocarbon-based oxygen carriers (PFCOC) have proven favourable for other organ transplants, their beneficial use for ex vivo lung perfusion (EVLP) still requires further investigation. In a rat model, we evaluated on a 4 h EVLP time the effects of PFCOC with either 28 °C or 37 °C perfusion temperatures. During EVLP at 28 °C with PFCOC, we recorded significantly lower lung pulmonary vascular resistance (PVR), higher dynamic compliance (Cdyn), significantly lower potassium and lactate levels, higher lung tissue ATP content, and significantly lower myeloperoxidase tissue activity when compared to the 37 °C EVLP with PFCOC. In the subnormothermic EVLP with or without PFCOC, the pro-inflammatory mediator TNFα, the cytokines IL-6 and IL-7, the chemokines MIP-3α, MIP-1α, MCP-1, GRO/KC as well as GM-CSF, G-CSF and the anti-inflammatory cytokines IL-4 and IL-10 were significantly lower. The 28 °C EVLP improved both Cdyn and PVR and decreased pro-inflammatory cytokines and pCO2 levels compared to the 37 °C EVLP. In addition, the 28 °C EVLP with PFCOC produced a significantly lower level of myeloperoxidase activity in lung tissue. Subnormothermic EVLP with PFCOC significantly improves lung donor physiology and ameliorates lung tissue biochemical and inflammatory parameters.

Volutrauma Increases Exhaled Pentanal in Rats: A Potential Breath Biomarker for Ventilator-Induced Lung Injury.

Mechanical ventilation injures lungs, but there are currently no reliable methods for detecting early injury. We therefore evaluated whether exhaled pentanal, a lipid peroxidation product, might be a useful breath biomarker for stretch-induced lung injury in rats. A total of 150 male Sprague-Dawley rats were investigated in 2 substudies. The first randomly assigned 75 rats to 7 hours of mechanical ventilation at tidal volumes of 6, 8, 12, 16, and 20 mL·kg-1. The second included 75 rats. A reference group was ventilated at a tidal volume of 6 mL·kg-1 for 10 hours 4 interventional groups were ventilated at a tidal volume of 6 mL·kg-1 for 1 hour, and then for 0.5, 1, 2, or 3 hours at a tidal volume of 16 mL.kg-1 before returning to a tidal volume of 6 mL·kg-1 for additional 6 hours. Exhaled pentanal was monitored by multicapillary column-ion mobility spectrometry. The first substudy included cytokine and leukocyte measurements in blood and bronchoalveolar fluid, histological assessment of the proportion of alveolar space, and measurements of myeloperoxidase activity in lung tissue. The second substudy included measurements of pentanal in arterial blood plasma, cytokine and leukocyte concentrations in bronchoalveolar fluid, and cleaved caspase 3 in lung tissue. Exhaled pentanal concentrations increased by only 0.5 ppb·h-1 (95% confidence interval [CI], 0.3-0.6) when rats were ventilated at 6 mL·kg-1. In contrast, exhaled pentanal concentrations increased substantially and roughly linearly at higher tidal volumes, up to 3.1 ppb·h-1 (95% CI, 2.3-3.8) at tidal volumes of 20 mL·kg-1. Exhaled pentanal increased at average rates between 1.0 ppb·h-1 (95% CI, 0.3-1.7) and 2.5 ppb·h-1 (95% CI, 1.4-3.6) after the onset of 16 mL·kg-1 tidal volumes and decreased rapidly by a median of 2 ppb (interquartile range [IQR], 0.9-3.2), corresponding to a 38% (IQR, 31-43) reduction when tidal volume returned to 6 mL·kg-1. Tidal volume, inspiratory pressure, and mechanical power were positively associated with pentanal exhalation. Exhaled and plasma pentanal were uncorrelated. Alveolar space decreased and inflammatory markers in bronchoalveolar lavage fluid increased in animals ventilated at high tidal volumes. Short, intermittent ventilation at high tidal volumes for up to 3 hours increased neither inflammatory markers in bronchoalveolar fluid nor the proportion of cleaved caspase 3 in lung tissue. Exhaled pentanal is a potential biomarker for early detection of ventilator-induced lung injury in rats.

Ghrelin Protects Lipopolysaccharide-Induced Acute Lung Injury Rats against Pulmonary Vascular Dysfunction by Inhibiting Inflammation

Objective. To determine the effect and mechanism of the anti-inflammatory agent ghrelin on pulmonary vascular dysfunction (PVD) in lipopolysaccharide- (LPS-) induced acute lung injury (ALI) rat models. Methods. Thirty-two adult male Sprague Dawley rats (n = 16/group) were randomly divided into ghrelin and saline groups, wherein ghrelin (10 nmol/kg) or saline was subcutaneously administered. After 30 min, eight rats from each group were randomly selected, and LPS (5 mg/kg) or saline was administered by intratracheal instillation to induce ALI. Four hours after establishing the ALI rat model, the mean pulmonary arterial pressure (mPAP), mean right ventricular systolic pressure (RVSP), levels of proinflammatory cytokines tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) in the bronchoalveolar lavage fluid (BALF), BALF cell count, wet-to-dry (W/D) lung weight ratios, and myeloperoxidase (MPO) activity in lung tissue for all four groups (ghrelin, ghrelin + ALI, saline, and saline + ALI) were measured. Immunohistochemical staining to detect alpha-smooth muscle actin (α-SMA) and proliferating cell nuclear antigen (PCNA) expression was performed to assess the intrapulmonary arterial wall thickness and the proliferation of smooth muscle cells, respectively. Results. The ghrelin-pretreated ALI rats showed lower mPAP, RVSP, PCNA expression, MPO activity, W/D lung weight ratio, TNF-α and IL-6 levels, and BALF cell count than the saline-pretreated ALI rats, but ghrelin had no effect on the intrapulmonary arterial wall thickness of ALI rats. Conclusion. Our results confirmed the association between inflammation and PVD in ALI and suggested that the suppression of inflammation by ghrelin pretreatment could protect LPS-induced ALI rats against PVD.

Subnormothermic Ex Vivo Lung Perfusion Temperature Improves Graft Preservation in Lung Transplantation.

: BackgroundNormothermic machine perfusion is clinically used to assess the quality of marginal donor lungs. Although subnormothermic temperatures have proven beneficial for other solid organ transplants, subnormothermia-related benefits of ex vivo lung perfusion (EVLP) still need to be investigated. Material and Methods: In a rat model, we evaluated the effects of 28 °C temperature on 4-h EVLPs with subsequent left lung transplantation. The recipients were observed for 2 h postoperatively. Lung physiology data were recorded and metabolic parameters were assessed. Results: During the 4-h subnormothermic EVLP, the lung oxygenation was significantly higher (p < 0.001), pulmonary vascular resistance (PVR) lower and dynamic compliance (Cdyn) higher when compared to the 37 °C EVLP. During an end-of-EVLP stress test, we recorded significantly higher flow (p < 0.05), lower PVR (p < 0.05) and higher Cdyn (p < 0.01) in the 28 °C group when compared to the 37 °C group. After the left lung transplantation, Cdyn and oxygenation improved in the 28 °C group, which were comparable to the 37 °C group. Chemokines RANTES, MIP-3α, MIP-1α MCP-1 GRO/KC and pro-inflammatory mediators GM-CSF, G-CSF and TNFα were significantly lower after the 28 °C EVLP and remained low in the plasma of the recipient rats after transplantation. The lungs of the 28 °C group showed significantly lowered myeloperoxidase activity and lowered levels of TNFα and IL-1β. Conclusions: Compared to the normothermic perfusion, the 28 °C EVLP improved Cdyn and PVR and reduced both the release of pro-inflammatory cytokines and myeloperoxidase activity in lung tissue. These observations were also observed after the left lung transplantation in the subnormothermic group. The 28 °C EVLP significantly improved biochemical, physiological and inflammatory parameters in lung donors.

Mesenteric Lymph Duct Ligation Alleviates Acute Lung Injury Caused by Severe Acute Pancreatitis Through Inhibition of High Mobility Group Box 1-Induced Inflammation in Rats

BackgroundAcute lung injury (ALI) is the most common complication and one of the leading causes of mortality of severe acute pancreatitis (SAP). Nevertheless, no effective therapeutic schemes are presently available.AimsTo investigate the effect and potential mechanism of mesenteric lymph duct ligation (MLDL) on experimental SAP-induced ALI.MethodsImmediately following MLDL, rats were subjected to SAP by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct. At 24 h after modeling, tissues were collected for morphological examination. The levels of TNF-α, IL-6, intercellular adhesion molecule-1 (ICAM1), diamine oxidase (DAO), and D-lactic acid (D-LA) in serum, and the myeloperoxidase (MPO) activity in lung tissues were determined. Moreover, the expressions of high mobility group box 1 (HMGB1), receptor of advanced glycation endproducts (RAGE), and NF-κB p65 at the mRNA and protein levels in lung tissues, and the expressions of HMGB1, RAGE, and TNF-α at the mRNA level in intestinal lymphoid tissues were evaluated.ResultsMLDL significantly attenuated the histological injury of the pancreas and lung and reduced the production of TNF-α, IL-6, and ICAM1. Besides, MLDL repressed the activity of MPO in the lung. However, the levels of serum DAO and D-LA were decreased without obvious morphological improvement in intestinal injury. Moreover, MLDL apparently reduced the up-regulation of HMGB1, RAGE, and NF-κB p65 in lung tissues, as well as the expressions of HMGB1, RAGE, and TNF-α in intestinal lymphoid tissues.ConclusionsMesenteric lymph was a source of harmful factors leading to SAP-ALI. MLDL could alleviate SAP-ALI probably by inhibiting HMGB1-induced production of inflammation factors.

Ferulic acid alleviates lipopolysaccharide-induced acute lung injury through inhibiting TLR4/NF-κB signaling pathway.

Ferulic acid (FA) exhibits anti-inflammatory, antidiabetic, antihyperlipidemic, antioxidant, neuroprotective, and antihypertensive effects. This study aimed to determine whether FA could ameliorate lipopolysaccharide (LPS)-induced inflammatory responses and acute lung injury (ALI) in mice. Mice were challenged with LPS intratracheally to induce ALI 1 h after 3 days of FA (25, 50, and 100 mg/kg) or dexamethasone (DEX; 5 mg/kg) administration. The lung tissues and bronchoalveolar lavage fluid (BALF) were collected 12 h after the LPS challenge. Pretreatment with FA or DEX could attenuate lung histopathological change, complement deposition, and lung wet-to-dry weight ratio of mice injured by LPS. Meanwhile, the influx of neutrophils and macrophages, as well as the production of proinflammatory cytokine (tumor necrosis factor-alpha, interleukin 1 beta [IL-1β], and IL-6), in BALF of ALI mice was significantly decreased. Moreover, FA or DEX markedly reversedthe LPS-induced elevation of myeloperoxidase activity and monocyte chemoattractant protein-1 level in lung tissues of ALI mice. In addition, the Western blot analysis demonstrated that FA or DEX effectively inhibited the LPS-induced activation of the toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway in lung tissues. The current study suggested that the alleviating effect of FA against LPS-induced ALI might be partially due to the inhibition of the inflammatory response via inactivation of the TLR4/NF-κB signaling pathway.

Exogenous Surfactant as a Pulmonary Delivery Vehicle for Budesonide In Vivo.

BackgroundLung inflammation is associated with many respiratory conditions. Consequently, anti-inflammatory medications, like glucocorticoids, have become mainstay intrapulmonary therapeutics. However, their effectiveness for treating inflammation occurring in the alveolar regions of the lung is limited by suboptimal delivery. To improve the pulmonary distribution of glucocorticoids, such as budesonide to distal regions of the lung, exogenous surfactant has been proposed as an ideal delivery vehicle for such therapies. It was therefore hypothesized that fortifying an exogenous surfactant (BLES) with budesonide would enhance efficacy for treating pulmonary inflammation in vivo.MethodsAn intratracheal instillation of heat-killed bacteria was used to elicit an inflammatory response in the lungs of male and female rats. Thirty minutes after this initial instillation, either budesonide or BLES combined with budesonide was administered intratracheally. To evaluate the efficacy of surfactant delivery, various markers of inflammation were measured in the bronchoalveolar lavage and lung tissue.ResultsAlthough budesonide exhibited anti-inflammatory effects when administered alone, delivery with BLES enhanced those effects by lowering the lavage neutrophil counts and myeloperoxidase activity in lung tissue. Combining budesonide with BLES was also shown to reduce several other pro-inflammatory mediators. These results were shown across both sexes, with no observed sex differences.ConclusionBased on these findings, it was concluded that exogenous surfactant can enhance the delivery and efficacy of budesonide in vivo.

Inhibitory functions of cardamonin against particulate matter-induced lung injury through TLR2,4-mTOR-autophagy pathways

Particulate matter with an aerodynamic diameter equal to or less than 2.5 μm (PM2.5) is a form of air pollutant that causes significant lung damage when inhaled. Cardamonin, a flavone found in Alpinia katsumadai Heyata seeds, has been reported to have anti-inflammatory and anticoagulative activity. The aim of this study was to determine the protective effects of cardamonin on PM2.5-induced lung injury. Mice were treated with cardamonin via tail-vein injection 30 min after the intratracheal instillation of PM2.5. The results showed that cardamonin markedly reduced the pathological lung injury, lung wet/dry weight ratio, and hyperpermeability caused by PM2.5. Cardamonin also significantly inhibited PM2.5-induced myeloperoxidase (MPO) activity in lung tissue, decreased the levels of PM2.5-induced inflammatory cytokines and effectively attenuated PM2.5-induced increases in the number of lymphocytes in the bronchoalveolar lavage fluid (BALF). And, cardamonin increased the phosphorylation of mammalian target of rapamycin (mTOR) and dramatically suppressed the PM2.5-stimulated expression of toll-like receptor 2 and 4 (TLR 2,4), MyD88, and the autophagy-related proteins LC3 II and Beclin 1. In conclusion, these findings indicate that cardamonin has a critical anti-inflammatory effect due to its ability to regulate both the TLR2,4-MyD88 and mTOR-autophagy pathways and may thus be a potential therapeutic agent against PM2.5-induced lung injury.

Thalictrum minus L. ameliorates particulate matter-induced acute lung injury in mice

Ethnopharmacological relevanceThalictrum minus L., which is widespread across Eurasia, is utilized as a folk medicine for treating dysentery, bedsore, fungal infection and lung inflammation in China, Mongolia and Iran. Aim of the studyA Mongolian folk medicinal plant named Thalictrum minus L. (TML) has been extensively used for the treatment of lung inflammation, bacterial and fungal infection and tuberculosis. Our present study aims to investigate the effectiveness of TML against particulate matter (PM)-induced acute lung injury (ALI) and the potential underlying mechanisms. Materials and methodsInitially, HPLC-Q-TOF was applied for the qualitative analysis and HPLC was used for quantitative analysis of main components in TML. Then, the mice model of ALI was induced by PM via intratracheally instilled with 50 mg/kg body weight of Standard Reference Material1648a (SRM1648a), and TML (10, 20, 40 mg/kg) were administered orally 1 h prior to PM. The efficacy and molecular mechanisms in the presence or absence of TML were elucidated. ResultsEleven main ingredients were detected in TML and the contents of homoorientin and berberine were quantified. Additionally, the results demonstrated that TML profoundly inhibited weight loss in mice and ameliorated lung pathological injury induced by PM. Furthermore, we also found that TML significantly decreased the lung wet to dry weight (W/D) ratios, reduced total protein in bronchoalveolar lavage fluid (BALF), and effectively attenuated PM-induced increased leukocyte and macrophages in BALF. Meanwhile, TML could pronouncedly inhibited myeloperoxidase (MPO) activity in lung tissues, decreased the PM-induced inflammatory cytokines including tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6) and interleukin-1β (IL-1β), reduced nitric oxide (NO) and increased superoxide dismutase (SOD) in BALF. In addition, TML markedly facilitated the expression of p-AMPK-Nrf2 and suppressed the expression of KEAP, prohibited the activation of the MAPKs-NLRP3/caspase-1 and cyclooxygenase-2 (COX2), and inhibited apoptotic pathways. ConclusionThese findings indicated that TML attenuated PM-induced ALI through suppressing the release of inflammatory cytokines and alleviating oxidative damage correlated with the AMPK-Nrf2/KEAP signaling pathways, MAPKs-NLRP3/caspase-1 signaling pathways, as well as apoptotic pathways.

Lipopolysaccharide-Induced Acute Lung Injury Is Associated with Increased Ran-Binding Protein in Microtubule-Organizing Center (RanBPM) Molecule Expression and Mitochondria-Mediated Apoptosis Signaling Pathway in a Mouse Model.

BackgroundAcute lung injury (ALI) is a severe and life-threatening disorder treated in intensive care units. This study aimed to determine molecules or associated signaling pathways that are involved in lipopolysaccharide (LPS)-induced inflammation in an ALI model.Material/MethodsAn ALI mouse model was established by administering LPS (25 mg/kg via intratracheal instillation). Thirty-two ALI mice were divided into Model-4 h, Model-8 h, Model-12 h, and Model-24 h groups, while another 8 mice without LPS treatment were assigned as the Control group. Hematoxylin-eosin (HE) staining was used to evaluate inflammation of lung tissues. Wet weight/dry weight (W/D) ratio and myeloperoxidase (MPO) activity of lung tissue in ALI mice were evaluated. Expressions of Bcl-2, Bcl-XL, Bak, Bax, cleaved caspase-3 (C-caspase-3), and Ran-binding protein in microtubule-organizing center (RanBPM) were determined using Western blot analysis.ResultsLPS administration caused obvious inflammatory cell infiltration of lung tissues in ALI mice. The W/D ratio of ALI mouse lung tissues was significantly higher in Model groups than in the Control group (p<0.05). MPO activity of ALI mice was remarkably higher in Model groups compared to the Control group (p<0.05). LPS-induced ALI model mice exhibited significantly higher levels of C-caspase 3 lung tissues compared to the Control group (p<0.05). LPS-induced ALI model mice had significantly lower Bcl-XL/Bcl-2 and remarkably higher Bak/Bax expression compared with the Control group (p<0.05). LPS-induced ALI model mice displayed obviously higher RanBPM expression than in the Control group (p<0.05).ConclusionsLipopolysaccharide-induced acute lung injury is associated with increased RanBPM molecule expression and with mitochondria-mediated apoptosis signaling pathway in a mouse model.