Rat Model Of Lung Injury Research Articles

Inhibition Mir-92a Alleviates Oxidative Stress and Apoptosis of Alveolar Epithelial Cells Induced by Lipopolysaccharide Exposure through TLR2/AP-1 Pathway.

Objective To probe into the role of miR-92a in alleviating oxidative stress and apoptosis of alveolar epithelial cell (AEC) injury induced by lipopolysaccharide (LPS) exposure through the Toll-like receptor (TLR) 2/activator protein-1 (AP-1) pathway. Methods Acute lung injury (ALI) rat model and ALI alveolar epithelial cell model were constructed to inhibit the expression of miR-92a/TLR2/AP-1 in rat and alveolar epithelial cells (AECs), to detect the changes of oxidative stress, inflammatory response, and cell apoptosis in rat lung tissues and AECs, and to measure the changes of wet-dry weight (W/D) ratio in rat lung tissues. Results Both inhibition of miR-92a expression and knockout of TLR2 and AP-1 gene could reduce LPS-induced rat ALI, alleviate pulmonary edema, inhibit oxidative stress and inflammatory response, and reduce apoptosis of lung tissue cells. In addition, the TLR2 and AP-1 levels in the lung tissues of ALI rats were noticed to be suppressed when inhibiting the expression of miR-92a, and the AP-1 level was also decreased after the knockout of TLR2 gene. Further, we verified this relationship in AECs and found that inhibition of miR-92a/TLR2/AP-1 also alleviated LPS-induced AEC injury, reduced cell apoptosis, and inhibited oxidative stress and inflammatory response. What is more, like that in rat lung tissue, the phenomenon also existed in AECs, that is, when the expression of miR-92a was inhibited, the expression of TLR2 and AP-1 was inhibited, and silencing TLR2 can reduce the expression level of AP-1. Conclusion MiR-92a/TLR2/AP-1 is highly expressed in ALI, and its inhibition can improve oxidative stress and inflammatory response and reduce apoptosis of AECs.

Do oral amino acid supplements facilitate the healing of rat lung injuries?

Prolonged air leaks following lung injury cause extended hospital stays. This study investigated the effect of nutritional supplements containing arginine, glutamine and β-hydroxy β-methyl butyrate, which were theoretically proven to accelerate wound healing, on air leak and wound healing parameters in a rat lung injury model. Twenty-eight female rats were randomly divided into 4 groups. Experimental groups were given glutamine (Resource Glutamine®) or a mixture of arginine, glutamine and β-hydroxy β-methyl butyrate (Abound®) as a dietary supplement at isonitrogenous and isocaloric doses. On day 3, standard sized lung injuries were created in all rats except the sham group. The rats were sacrificed on day 6, and the lungs were removed for air-leak threshold pressure measurement and histopathological and biochemical analyses. Loss of body mass was greater in the glutamine group than in the other groups (P = 0.004). Rats that received the amino acid mixture had better results for mature collagen fibre density (P = 0.002) and inflammation suppression (P = 0.003). The sham group had higher values for air-leak threshold pressure and all other histochemical parameters compared to the other groups. Hydroxyproline level did not differ significantly in any of the groups. Our results indicated that an oral amino acid mixture was effective in the healing of lung injuries. Isolated glutamine supplementation had an adverse impact on body mass. Randomized clinical studies including larger series are needed. Hydroxyproline does not seem to be a suitable marker for this purpose.

Emodin alleviates LPS-induced inflammatory response in lung injury rat by affecting the function of granulocytes

BackgroundAcute lung injury (ALI) and/or acute respiratory distress syndrome (ARDS) are critical life-threatening syndromes characterized by the infiltration of a large number of granulocytes (mainly neutrophils) that lead to an excessive inflammatory response. Emodin (Emo) is a naturally occurring anthraquinone derivative and an active ingredient of Chinese medicine. It is believed to have anti-inflammatory effects. In this study, we examined the impact of Emo on the pulmonary inflammatory response and the granulocytes function in a rat model of lipopolysaccharide (LPS)-induced ALI.ResultsTreatment with Emo protected rat against LPS-induced ALI. Compared to untreated rat, Emo-treated rat exhibited significantly ameliorated lung pathological changes and decreased tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β). However, Emo has no protective effect on the rat model of acute lung injury with granulocyte deficiency. In addition, treatment with Emo enhanced the bactericidal capacity of LPS-induced granulocytes via the up-regulation of the ability of granulocytes to phagocytize bacteria and generate neutrophil extracellular traps (NETs). Emo also downregulated the respiratory burst and the expression of reactive oxygen species (ROS) in LPS-stimulated granulocytes, alleviating the damage of granulocytes to surrounding tissues. Finally, Emo can accelerate the resolution of inflammation by promoting apoptosis of granulocytes.ConclusionOur results provide the evidence that Emo could ameliorates LPS-induced ALI via its anti-inflammatory action by modulating the function of granulocytes. Emo may be a promising preventive and therapeutic agent in the treatment of ALI.

Sine ventilation in lung injury models: a new perspective for lung protective ventilation

Mechanical ventilation is associated with the risk of ventilator induced lung injury. For reducing lung injury in mechanically ventilated patients, the application of small tidal volumes and positive end-expiratory pressures has become clinical standard. Recently, an approach based on linear airway pressure decline and decelerated expiratory flow during expiration implied lung protective capacities. We assumed that ventilation with a smoothed, i.e. sinusoidal airway pressure profile may further improve ventilation efficiency and lung protection. We compared the effects of mechanical ventilation with sinusoidal airway pressure profile (SINE) regarding gas exchange, respiratory system compliance and histology to conventional volume and pressure controlled ventilation (VCV and PCV) and to VCV with flow-controlled expiration (FLEX) in two rat models of lung injury, tween induced surfactant depletion and high tidal volume mechanical ventilation. In both lung injury models ventilation with SINE showed more efficient CO2 elimination and blood oxygenation, improved respiratory system compliance and resulted in lower alveolar wall thickness, compared to VCV, PCV and FLEX. Optimization of the airway pressure profile may provide a novel means of lung protective mechanical ventilation.

Effect of different doses of dexmedetomidine on lung function and tissue cell apoptosis in a rat model of hyperoxic acute lung injury

Purpose: To study the effect of different doses of dexmedetomidine on lung function and lung tissue cell apoptosis in a rat model of hyperoxic acute lung injury.
 Methods: Five groups of healthy male Sprague-Dawley rats were used: normal rats, untreated hyperoxic rats, and hyperoxic rats given 3 different doses of dexmedetomidine, with 20 rats in each group. The levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were determined usingenzyme-linked immunosorbent assay (ELISA). Parietal paraffin cuts were taken from the right upper lobe for measurement of apoptosis using in situ terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), and the apoptosis index was calculated.
 Results: At 24 and 48 h, the levels of IL-6 and TNF-α in the hyperoxia model group were significantly higher than those in the normal control group, and their levels in the middle- and high-dose groups were markedly lowered, relative to untreated hyperoxia rats (p < 0.05). Apoptosis index in the hyperoxia model rats significantly increased, relative to normal rats (p < 0.05). The apoptosis index in the mediumand high-dose groups decreased significantly (p < 0.05).
 Conclusion: Dexmedetomidine inhibits inflammatory responses caused by high concentration of oxygen inhalation, minimizes lung injury, improves lung function and inhibits lung apoptosis.
 Keywords: Dexmedetomidine, Hyperoxia, Acute lung injury, Lung function, Apoptosis

Lipoxin A4 alleviates lung injury in sepsis rats through p38/MAPK signaling pathway.

The aim of the study was to explore the effect of lipoxin A4 (LXA4) on lung injury in sepsis rats through the p38/mitogen-activated protein kinase (MAPK) signaling pathway. Sprague-Dawley rats were used for the study. The rat model of sepsis-induced acute lung injury was established via cecal ligation (Sepsis group, n=20). LXA4 (0.1 mg/kg) was injected at 6 h after modeling (Treatment group, n=20), and a The Control group (n=20) was also set up. The 7-day survival rate was 100% in The Control group, and LXA4 raised the survival rate of rats in the Sepsis group from 40% to 60% (P<0.01). Alveolar fluid clearance (AFC) significantly declined and the wet/dry weight (W/D) ratio of lung tissues rose remarkably in the Sepsis group compared with those in the Control group, while LXA4 restored AFC and reduced the W/D ratio of lung tissues (P<0.05), suggesting that LXA4 treatment reduces lung fluids and partially enhances AFC, thus lowering the W/D ratio of lung. The total cell count, polymorphonuclear neutrophils (PMN) percentage and concentration of tumor necrosis factor-α (TNF-α) and interleukin (IL)-6 in bronchoalveolar lavage fluid (BALF) were obviously increased in the Sepsis group compared with those in the Control group, while they were markedly decreased in the Treatment group (P<0.05). The activity of myeloperoxidase (MPO) in lung tissue homogenate was evidently higher in the Sepsis group than that in The Control group, while it was notably lower in the Treatment group than that in the Sepsis group after LXA4 treatment (P<0.05). Moreover, it was observed microscopically that the morphology of lung tissues was intact in the Control group. Finally, the results of Western blotting manifested that the p-p38/ MAPK protein expression was remarkably increased in the Sepsis group, indicating the activation of the p38/MAPK pathway, while it was remarkably decreased in the Treatment group, indicating the inhibited activity of the pathway (P<0.05). LXA4 has an anti-inflammatory effect on sepsis rats with lung injury, and such effect is related to the p38/MAPK signaling pathway.

The Changes of Twist1 Pathway in Pulmonary Microvascular Permeability in a Newborn Rat Model of Hyperoxia-Induced Acute Lung Injury.

Background: Bronchopulmonary dysplasia (BPD) is a chronic lung disease in preterm infants, which is characterized by alveolar and vascular dysplasia and increased vascular permeability. Hyperoxia is a critical factor in the pathogenesis of BPD, hyperoxia-induced acute lung injury (HALI) model has similar pathological manifestations as human BPD, therefore, may provide insight into the pathogenesis of human BPD. Studies have shown that Twist1 regulates pulmonary vascular permeability of LPS-induced lung injury through the Ang-Tie2 pathway. However, the effect of Twist1 pathway on vascular permeability in HALI has not been reported.Methods: We randomly exposed newborn rats to the room air or hyperoxia for 14 days. Lung histopathology, immunofluorescence, vascular permeability, mRNA and protein expression was assessed on day 1,7,14.Results: Our results verified that hyperoxia caused alveolar and vascular developmental disorders and increased pulmonary vascular permeability, which was consistent with previous findings. In hyperoxia-exposed rat lungs, the expressions of Twist1, Ang1, Tie1, Tie2, and pTie2 were significantly reduced, whereas the expression of Ang2 was significantly increased. Next, we observed a significant down-regulation of the Akt/Foxo1 pathway.Conclusion: In HALI, the pulmonary microvascular permeability was increased, accompanied by changes in Twist1-Tie2 pathway which combined to Angs, and downregulation of Tie1 and Akt/Foxo1 pathway.

Protective effects of aerosolized pulmonary surfactant powder in a model of ventilator-induced lung injury.

Mechanical ventilation may contribute to the impairment of the pulmonary surfactant system, which is one of the mechanisms leading to the progression of acute lung injury. To investigate the potential protective effects of pulmonary surfactant in a rat model of ventilator-induced lung injury, the surfactant powder was aerosolized using an in-house made device designed to deliver the aerosolized powder to the inspiratory line of a rodent ventilator circuit. Rats were randomized to (i) administration of aerosolized recombinant surfactant protein C based pulmonary surfactant, (ii) intratracheally instillation of the same surfactant re-constituted in saline, and (iii) no treatment. Animals were monitored during 2h of high-tidal volume mechanical ventilation, after which rats were sacrificed, and further analysis of lung mechanics and surfactant function were completed. Blood gas measurements during ventilation showed extended maintenance of oxygen levels above 400mmHg in aerosol treated animals over non-treated and instilled groups, while total protein analysis showed reduced levels in the aerosol compared to non-treated groups. Dynamic captive bubble surface tension measurements showed the activity of surfactant recovered from aerosol treated animals is maintained below 1 mN/m. The prophylactic treatment of aerosolized surfactant powder reduced the severity of lung injury in this model.

Protective effects of hesperetin on lipopolysaccharide-induced acute lung injury in a rat model.

In this experimental study, we aimed to investigate the effects of hesperetin, a natural flavonoid, on a lipopolysaccharideinduced acute lung injury model in rats. Between March 2019 and May 2019, a total of 18 adult male Wistar albino rats, weighing approximately 250 to 300 g, were randomly divided into three groups as control, lipopolysaccharide, and lipopolysaccharide + hesperetin groups (n=6 in each group). The wet/dry weight ratio of lung tissue was determined. Histopathological changes were examined using light and scanning electron microscopy. Pulmonary nuclear factor-kappa beta, inducible nitric oxide synthase, and alpha-smooth muscle antigen activity were determined with indirect immunohistochemical methods. Pulmonary apoptosis was detected with the terminal deoxynucleotidyl transferase dUTP nick-end labeling method. Tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6, and interleukin-10 concentrations were measured with enzyme-linked immunosorbent assay. Treatment with hesperetin significantly improved the architecture of lung tissue and reduced the wet/dry weight ratio, nuclear factor-kappa beta, inducible nitric oxide synthase, and alphasmooth muscle antigen expression, pulmonary apoptosis, and levels of proinflammatory cytokines. Our study results suggest that hesperetin has a potent protective effect against lipopolysaccharide-induced acute lung injury in rats via suppression of the proinflammatory cytokine cascade, nuclear factor-kappa beta, signaling pathway activation, and apoptosis.

Down-regulation of lncRNA CASC9 aggravates sepsis-induced acute lung injury by regulating miR-195-5p/PDK4 axis.

Long non-coding RNA (lncRNA) cancer susceptibility candidate 9 (CASC9) is reported to be linked to cancers. This research aims to explore the role and possible mechanism of CASC9 in lung injury induced by sepsis. Lipopolysaccharide (LPS) induced human small airway epithelial cells (HSAECs) were established in vitro to mimic sepsis-induced lung injury. The effects of CASC9 and miR-195-5p on HSAECs viability were studied by CCK-8 assay. Interactions between CASC9 and miR-195-5p were determined by bioinformatics analysis, RT-PCR, dual luciferase reporter assay, and RNA immunoprecipitation assay. Pyruvate dehydrogenase kinase 4 (PDK4) and apoptosis-related molecules including Bcl2 and Bad were detected by western blot. Additionally, sepsis-induced lung injury model in rats was established by intraperitoneal injection of LPS in vivo to validate the demonstrations of in vitro studies. CASC9 was markedly down-regulated while miR-195-5p was significantly up-regulated in HSAECs treated by LPS and lung tissues of rats with sepsis. CASC9 interacted with miR-195-5p, and negatively regulated its expression level. Overexpression of CASC9 or transfection of miR-195-5p inhibitors significantly promoted the viability of HSAECs. The transfection of miR-195-5p mimics effected oppositely. For mechanism, miR-195-5p targeted the 3'UTR of pyruvate dehydrogenase kinase 4 (PDK4) gene and depressed the protein level, and PDK4 was regulated indirectly by CASC9. Restoration of CASC9 in the lung tissues of rats with sepsis ameliorated lung injury. CASC9 protects lung epithelial cells from sepsis-induced injury via regulating miR-195-5p/PDK4 axis.

Maresin Conjugates in Tissue Regeneration 1 improves alveolar fluid clearance by up-regulating alveolar ENaC, Na, K-ATPase in lipopolysaccharide-induced acute lung injury.

Maresin Conjugates in Tissue Regeneration 1 (MCTR1) is a newly identified macrophage‐derived sulfido‐conjugated mediator that stimulates the resolution of inflammation. This study assessed the role of MCTR1 in alveolar fluid clearance (AFC) in a rat model of acute lung injury (ALI) induced by lipopolysaccharide (LPS). Rats were intravenously injected with MCTR1 at a dose of 200 ng/rat, 8 hours after administration of 14 mg/kg LPS. The level of AFC was then determined in live rats. Primary rat ATII (Alveolar Type II) epithelial cells were also treated with MCTR1 (100 nmol/L) in a culture medium containing LPS for 8 hours. MCTR1 treatment improved AFC (18.85 ± 2.07 vs 10.11 ± 1.08, P < .0001) and ameliorated ALI in rats. MCTR1 also significantly promoted AFC by up‐regulating epithelial sodium channel (ENaC) and Na+‐K+‐adenosine triphosphatase (Na, K‐ATPase) expressions in vivo. MCTR1 also activated Na, K‐ATPase and elevated phosphorylated‐Akt (P‐Akt) by up‐regulating the expression of phosphorylated Nedd4‐2 (P‐Nedd4‐2) in vivo and in vitro. However, BOC‐2 (ALX inhibitor), KH7 (cAMP inhibitor) and LY294002 (PI3K inhibitor) abrogated the improved AFC induced by MCTR1. Based on the findings of this study, MCTR1 may be a novel therapeutic approach to improve reabsorption of pulmonary oedema during ALI/acute respiratory distress syndrome (ARDS).

Effects of nebulized antithrombin and heparin on inflammatory and coagulation alterations in an acute lung injury model in rats

BackgroundDuring acute respiratory distress syndrome, proinflammatory mediators inhibit natural anticoagulant factors, which alter the normal balance between coagulation and fibrinolysis leading to a procoagulant state. We hypothesize that pulmonary administration of anticoagulants might be beneficial to treat acute respiratory distress syndrome for their anticoagulant and antiinflammatory effects and reduce the risk of systemic bleeding. ObjectivesOur aim is to study the effects of nebulized antithrombin (AT) and combined AT and heparin in an animal model of acute lung injury. MethodsAcute lung injury was induced in rats by the intratracheal administration of hydrochloric acid and lipopolysaccharide. AT alone (500 IU/kg body weight) or combined with heparin (1000 IU/kg body weight) were nebulized after the injury. Control groups received saline instead. Blood, lung tissue, bronchoalveolar lavage, and alveolar macrophages (AM) isolated from bronchoalveolar lavage were collected after 48 hours and analyzed. ResultsNebulized anticoagulant treatments reduced protein concentration in the lungs and decreased injury‐mediated coagulation factors (tissue factor, plasminogen activator inhibitor‐1, plasminogen, and fibrinogen degradation product) and inflammation (tumor necrosis factor α and interleukin 1β) in the alveolar space without affecting systemic coagulation and no bleeding. AT alone reduced fibrin deposition and edema in the lungs. Heparin did not potentiate AT coagulant effect but promoted the reduction of macrophages infiltration into the alveolar compartment. Anticoagulants reduced nuclear factor‐kB downstream effectors in AM. ConclusionsNebulized AT and heparin attenuate lung injury through decreasing coagulation and inflammation without altering systemic coagulation and no bleeding. However, combined AT and heparin did not produce a synergistic effect.

Preconditioning rats with three lipid emulsions prior to acute lung injury affects cytokine production and cell apoptosis in the lung and liver

BackgroundCritically ill patients are at higher risk having acute lung injury (ALI) and more often in need of parenteral nutrition. We sought to study whether preconditioning with representative of lipid emulsions for one week could benefit rats from ALI.MethodsUsing a lipopolysaccharide (LPS)-induced ALI rat model and techniques such as polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining.ResultsPGE2 production in the serum was highest in the LPS group, followed with Intralipid group, and the PGE2 level of these two groups was significantly (P < 0.05) higher than the rest. Intralipid conditioning caused significantly less production of LTB4 than the LPS, Clinoleic, or Omegaven group. In contrast to Intralipid, rats pretreated with Clinoleic or Omegaven significantly decreased their production of inflammatory mediators (IL-1 β, IL-6 and TNF-α), had less apoptosis in the lung tissues, and Omegaven greatly improved liver function upon lipopolysaccharide (LPS) challenge.ConclusionsIn an ALI setting, preconditioning with Omegaven or Clinoleic was better than Intralipid in decreasing the intensity of the cytokine storm and apoptosis caused by LPS challenge, and Omegaven in addition had the potential to improve liver function. The results from the present study set a basis for further investigation of the molecular mechanisms of ALI, including the up- and downstream pathways of proinflammatory factor production, in search of (small) molecules intervening with the pathogenesis of ALI in order to translate relevant research findings into clinical benefit for patients with ALI. The use of Omegaven or Clinoleic, particularly in patients with ALI, is still characterized by uncertainty due to a lack of relevant studies. Future investigations must specifically focus on the route of administration and mode of application (enteral vs. parenteral/bolus vs. continuous), determining an optimal dose of Omegaven or Clinoleic, and the defining the best timepoint(s) for administration. Critically ill patients are at higher risk having acute lung injury (ALI) and more often in need of parenteral nutrition. The effect of lipid emulsion via parenteral nutrition on liver function was first time evaluated in rats in an ALI setting. The comparison of three forms of lipid emulsion in a rat model of acute lung injury was first time studied. The fish oil-based lipid emulsion decrease in PGE 2 and increase in LTB 4 was first time reported.

Desflurane pretreatment can reduce sepsis-evoked lung injury in rats via inhibiting STAT3 pathway.

The purpose of this study was to investigate the effect of desflurane (Des) pretreatment on sepsisevoked lung injury in rats and its mechanism. The rat model of sepsis-evoked lung injury was prepared using lipopolysaccharide (LPS), while rat lung mesenchymal cell (MSC) model was cultured in vitro, followed by Des pretreatment or inhibitor S31-201 culture. The degree of lung tissue injury was analyzed by Hematoxylin-eosin (HE) staining. The expression levels of interleukin (IL)-6, IL-1β and tumor necrosis factor (TNF)-α in the serum of rats were detected by enzyme-linked immunosorbent assay (ELISA). One-step terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay was utilized to determine the apoptosis levels of lung tissues and MSCs cultured in vitro. The expressions of the signal transducer and activator of transcription 3 (STAT3) pathway in rat lung tissues and MSCs were detected by Western blotting. After modeling, LPS induced the lung injury in rats, the expression levels of IL-6, IL-1β and TNF-α were up-regulated (P<0.05), the apoptosis rate was increased (P<0.05), and phosphorylated-Janus kinase 2 (p-JAK2) and phosphorylated-STAT3 (p-STAT3) protein expressions were up-regulated (P<0.05). Des pretreatment can alleviate LPS-induced lung injury, down-regulate IL-6, IL-1β and TNF-α expression levels (P<0.05), reduce apoptosis (P<0.05), and downregulate p-JAK2 and p-STAT3 protein levels (P<0.05). LPS induced an increase in apoptosis rate of MSCs (P<0.05) and the up-regulation of p-STAT3 protein expression (P<0.05). Both Des pretreatment and S31-201 inhibitor culture could reduce the apoptosis rate (P<0.05) and down-regulate p-STAT3 protein level (P<0.05). Des pretreatment can reduce sepsis-evoked lung injury in rats, which may be related to the inhibition of protein expressions of STAT3 pathway.

The Effects of Dexmedetomidine in a Rat Model of Sepsis-Induced Lung Injury are Mediated Through the Adenosine Monophosphate-Activated Protein Kinase (AMPK)/Silent Information Regulator 1 (SIRT1) Pathway.

BackgroundThis study aimed to investigate the effects of dexmedetomidine in a rat model of sepsis-induced lung injury and the role of the adenosine monophosphate-activated protein kinase (AMPK) gene and silent information regulator 1 (SIRT1) gene signaling pathway.Material/MethodsSixty 28-week-old healthy male Sprague-Dawley rats were randomly divided into three groups, the sham group, the model group, and the dexmedetomidine-treated group. The rat model of sepsis-induced lung injury was developed by surgical cecal ligation and puncture. Lung tissues examined histologically in the three study groups. Cell apoptosis was measured using the TUNEL assay, and the expression of inflammatory cytokines, tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and IL-10 were measured in rat lung tissue by enzyme-linked immunosorbent assay (ELISA). Apoptosis-associated proteins and AMPK/SIRT1 pathway-associated protein expression levels were detected using Western blot.ResultsDexmedetomidine significantly increased the survival rate and reduced the body temperature of rats in the model group with sepsis-induced lung injury, reduced lung injury, significantly reduced apoptosis in lung tissues, and reduced the expression levels of TNF-α, and IL-1β, and increased the levels of IL-10. Dexmedetomidine significantly reduced the expression of caspase-3 in the rat lung tissue (P<0.01), and significantly increased the expression of Bcl-2/Bax and the phosphorylation levels of AMPK, SIRT1, nuclear factor-κB (NF-κB), and forkhead box class O 3a (FOXO3a).ConclusionsIn a rat model of sepsis-induced lung injury, dexmedetomidine reduced lung damage by activating the AMPK/SIRT1 signaling pathway and reduced the expression of inflammatory cytokines and cell apoptosis.

Naringin Attenuated Acute Lung Injury in Rat Model with Acute Pancreatitis in Pregnancy through Inactivation of p38 MAPK Pathway

Acute pancreatitis in pregnancy can cause fetal lung injury. Naringin exhibits ant-inflammation effect against pulmonary injuries. However, whether naringin can alleviate lung injury associated with acute pancreatitis in pregnancy has not been elucidated. Establishment of acute pancreatitis in pregnancy model by sodium taurocholate showed that sodium taurocholate induced obvious pathological changes in pancreas. Histopathological changes in lungs were also aggravated post sodium taurocholate treatment with enhanced inflammation of neutrophils, thickened alveolar walls and alveolus collapse. Diagnostic blood tests for acute pancreatitis in pregnancy indicated that serum amylase and lipase were increased post sodium taurocholate treatment. Sodium taurocholate-induced rats were intragastrically administered with naringin to investigate the protective effect of naringin on acute lung injury induced by acute pancreatitis in pregnancy. Results revealed that administration of naringin could attenuate pathological changes in pancreas and lungs and decrease amylase and lipase. Moreover, naringin treatment attenuated sodium taurocholate-induced increase in inflammatory cytokines, including tumor necrosis factor (TNF)-α, interleukin (IL)-6/1β in lungs. Sodium taurocholate-induced increase in phosphorylation of p38 was also reduced post naringin treatment. In conclusion, naringin could ameliorate acute lung injury and inflammation induced by acute pancreatitis in pregnancy by inhibiting the p38 pathway.

Oral administration of Ulmus davidiana extract suppresses interleukin-1β expression in LPS-induced immune responses and lung injury.

Ulmus davidiana (UD) is a traditional Korean herb medicine that is used to treat inflammatory disorders. UD has been shown to modulate a number of inflammatory processes in vitro or in vivo studies. However, the molecular mechanisms of UD on lipopolysaccharide (LPS)-induced acute lung injury remain to be understood. The primary objective of this study is to determine the effect of UD bark water extract on LPS-induced immune responses and lung injury using both in vitro and in vivo models. RAW 264.7 cells and a rat model of acute lung injury (ALI) were used to study the effects of UD on several parameters. Nitrite level, lactate dehydrogenase (LDH) level, and superoxide dismutase (SOD) activities were measured. Tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), and plasma transaminase activities in blood were also determined. Pathological investigations were also performed. LPS infusion resulted in elevated IL-1β mRNA expression, nitrite levels, TNF-α expression, and IL-1β expression in RAW 264.7 cells. LPS infusion also increased levels of nitrite/nitrate, total protein, LDH, and TNF-α in bronchoalveolar lavage fluid, but reduced SOD levels in ex vivo and in vivo models. UD administration ameliorated all these inflammatory markers. In particular, treatment with UD reduced LPS-induced nitrite production in RAW 264.7 cells in a dose-dependent manner. UD treatment also counteracted the LPS-induced increase in alanine aminotransferase (ALT) and aspartate transaminase (AST) activity in rat plasma, leading to a significant reduction in ALT and AST activity. The results revealed that UD treatment reduces LPS-induced nitrite production, IL-1β mRNA expression, and TNF-α expression. In addition, LPS-induced decrease in SOD level is significantly elevated by UD administration. These results indicate that UD extract merits consideration as a potential drug for treating and/or preventing ALI.

Effect of bovine lactoferrin as a novel therapeutic agent in a rat model of sepsis-induced acute lung injury

Sepsis is a serious clinical condition resulting from severe infection. High rates of mortality and tissue damage have been reported in intensive care unit (ICU) patients with sepsis. Bovine lactoferrin (BLF) is a well-known 80-kDa glycoprotein in the transferrin family that inhibits sepsis in low-birth-weight neonates. The present study investigated the protective effects of BLF in a rat model of sepsis-induced acute lung injury (ALI). The wet/dry ratio, lipid peroxidation, antioxidant markers, total protein, total cell count, inflammatory markers and myeloperoxidase (MPO) levels were assessed. Histopathological analysis was also carried out. BLF treatment reduced the wet/dry ratio of lung tissue by 30.7% and 61.3%, and lipid peroxidation by 22.3% and 67%, at concentrations of 100 and 200 mg/kg, respectively. Superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (Gpx) and catalase were increased by more than 50% under treatment with 200 mg/kg BLF. Inflammatory markers, neutrophils, lymphocytes and total cell count were reduced by more than 50% under treatment with 200 mg/kg BLF. BLF treatment significantly reduced MPO activity, by 28.2% and 74.3%, at concentrations of 100 and 200 mg/kg, respectively. Neutrophilic infiltration and edema were observed in control rats. However, BLF treatment restored intestinal microvilli to the normal range and reduced inflammatory cell invasion. Collectively, these results suggest that BLF is an effective therapeutic agent against sepsis-induced ALI.

Effect of penehyelidine hydrochloride on TIPE2-TLR4-MyD88 signaling pathway in a rat model of traumatic acute lung injury

Objective To evaluate the effect of penehyelidine hydrochloride (PHCD) on tumor necrosis factor α-induced protein 8-like-2 (TIPE2)-Toll-like receptor 4 (TLR4)-myeloid differentiation factor 88 (MyD88) signaling pathway in a rat model of traumatic acute lung injury (ALI). Methods Thirty SPF healthy male Sprague-Dawley rats, aged 8 weeks, weighing 190-210 g, were divided into 3 groups (n=15 each) by a random number table method: sham operation group (group Sham), traumatic ALI group (group ALI) and group PHCD.ALI was induced by blunt chest trauma in ALI and PHCD groups.PHCD 2 mg/kg was intraperitoneally injected immediately after blunt chest trauma in group PHCD.The rats were sacrificed and lung tissues were removed at 8 h after the model was successfully established for examination of the pathological changes and ultrastructure of lung tissues (with a light microscope or an electron microscope) and for determination of the wet to dry weight ratio (W/D ratio) and expression of TLR4 and MyD88 in lung tissues. Results Compared with group Sham, the W/D ratio was significantly increased, TIPE2 expression was down-regulated, and the expression of TLR4 and MyD88 was up-regulated in ALI and PHCD groups (P<0.05). Compared with group ALI, the W/D ratio was significantly decreased, TIPE2 expression was up-regulated, and the expression of TLR4 and MyD88 was down-regulated (P<0.05), and the pathological changes of lung tissues and ultrastructure were significantly attenuated in group PHCD. Conclusion The mechanism by which PHCD reduces traumatic AIL is related to activating TIPE2-TLR4-MyD88 signaling pathway in rats. Key words: Cholinergic antagonists; Acute lung injury; Ubiquitin-specific proteases; Toll-like receptor 4; Myeloid differentiation factor 88

Abstract P2004: Neural Inflammation in Stellate Ganglia Mediates Lung Injury-Induced Arrhythmogenesis

Background: People who suffer lung injury, incurred through a variety of means, are at greatly increased risk of developing cardiac arrhythmias. Treatment options remain limited. We propose that stellate ganglia neuro-inflammation contributes to lung injury-induced arrhythmogenesis. Methods: We created lung injury in adult Sprague-Dawley rats by a single tracheal instillation of Bleomycin (Bleo, 2.5 mg/kg), and used Saline instillation as a control. We recorded ECGs in conscience, freely moving Bleo and Saline rats treated with and without oral minocycline (20 mg/kg/day for 4 weeks, an anti-inflammatory drug to inhibit microglia/macrophage activation) using implantable radio-telemeters. During terminal experimentation we investigated the effect of minocycline on isolated electrical stellate stimulation-induced cardiac arrhythmias in Bleo rats. Results: Bleo rats exhibited lung lesions at necropsy and lung fibrosis histologically. Bleo rats, on average, had more premature ventricular contractions (PVCs) than Saline rats, an effect largely prevented by chronic treatment with minocycline. (PVC data 1-wk post Bleo: Saline 22±12, Bleo 481±394*#, Bleo+Mino 24±9. PVC data 2-wks post Bleo: Saline 6±2, Bleo 255±165*, Bleo+Mino 21±8. Data are AVG±SEM number of PVCs over 24-hr, n=5-6 for all groups. *P&lt;0.05 between Bleo vs. Saline, #P&lt;0.05 Bleo vs. Bleo+Mino). Isolated electrical stellate ganglia stimulation caused a frequency-dependent increase in heart rate without arrhythmias in normal rats but in Bleo rats triggered a significant number of PVCs, indicating stellate ganglia excitability post lung injury. This effect was greatly reduced in Bleo rats receiving minocycline. Since our isolated stellate preparation is decentralized, these data clearly suggest a local protective effect of minocycline on stellate ganglia in Bleo rats. Immunofluorescence data suggested that compared to sham-operated rats, the number of Iba-1-positive (a macrophage marker) cells in stellate ganglia of bleomycin-treated rats was significantly increased at 1 week post lung injury and lasted for at least 4 weeks. Conclusion: Our data showed that stellate ganglia neuroinflammation contributes to arrhythmogenesis in our Bleo lung injury rat model.