Functional changes of pulmonary surfactant in rats with lung injury induced by endotoxin

We studied the functional changes of pulmonary surfactant （PS） in acutelung injury models produced by endotoxin injection (E.coli O55B5) in rats.The sur-face properties of the lung lavage liquid and the total phospholipids （TPL） ex-tracted from it were assessed on a modified Wilhelmy film balance.γ-A isothermof the lavage liquid revealed an increase in minimum surface tension and a de-crease in hysteresis area,recruitment index and stability index,whereas that ofTPL extracted from it did not show any change except for hysteresis area.Thesurface activity correlates positively with the TPL content but negatively with thetotal protein content in the lavage liquid.The findings indicated that there was adysfunction of PS in rats with the lung injury induced by endotoxin,suggestingthat the function deficiency of PS might be caused by decreased phospholipidsand increased proteins in the alveoli.

Alleviation of acute pancreatitis-associated lung injury by inhibiting the p38 mitogen-activated protein kinase pathway in pulmonary microvascular endothelial cells

BACKGROUND Previous reports have suggested that the p38 mitogen-activated protein kinase signaling pathway is involved in the development of severe acute pancreatitis(SAP)-related acute lung injury(ALI).Inhibition of p38 by SB203580 blocked the inflammatory responses in SAP-ALI.However,the precise mechanism associated with p38 is unclear,particularly in pulmonary microvascular endothelial cell(PMVEC)injury.AIM To determine its role in the tumor necrosis factor-alpha(TNF-α)-induced inflammation and apoptosis of PMVECs in vitro.We then conducted in vivo experiments to confirm the effect of SB203580-mediated p38 inhibition on SAP-ALI.METHODS In vitro,PMVEC were transfected with mitogen-activated protein kinase kinase 6(Glu),which constitutively activates p38,and then stimulated with TNF-α.Flow cytometry and western blotting were performed to detect the cell apoptosis and inflammatory cytokine levels,respectively.In vivo,SAP-ALI was induced by 5%sodium taurocholate and three different doses of SB203580(2.5,5.0 or 10.0 mg/kg)were intraperitoneally injected prior to SAP induction.SAP-ALI was assessed by performing pulmonary histopathology assays,measuring myeloperoxidase activity,conducting arterial blood gas analyses and measuring TNF-α,interleukin(IL)-1βand IL-6 levels.Lung microvascular permeability was measured by determining bronchoalveolar lavage fluid protein concentration,Evans blue pulmonary cells was confirmed by performing a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling analysis and examining the Bcl2,Bax,Bim and cle-caspase3 levels.The proteins levels of P-p38,NFκB,IκB,P-signal transducer and activator of transcription-3,nuclear factor erythroid 2-related factor 2,HO-1 and Myd88 were detected in the lungs to further evaluate the potential mechanism underlying the protective effect of SB203580.RESULTS In vitro,mitogen-activated protein kinase(Glu)transfection resulted in higher apoptotic rates and cytokine(IL-1βand IL-6)levels in TNF-α-treated PMVECs.In vivo,SB2035080 attenuated lung histopathological injury,decreased inflammatory activity(TNF-α,IL-1β,IL-6 and myeloperoxidase)and preserved pulmonary function.Furthermore,SB203580 significantly reversed changes in the bronchoalveolar lavage fluid protein concentration,Evans blue accumulation,terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cell numbers,apoptosis-related proteins(cle-caspase3,Bim and Bax)and endothelial microstructure.Moreover,SB203580 significantly reduced the pulmonary P-p38,NFκB,P-signal transducer and activator of transcription-3 and Myd88 levels but increased the IκB and HO-1 levels.CONCLUSION p38 inhibition may protect against SAP-ALI by alleviating inflammation and the apoptotic death of PMVECs.

Drug repurposing of histone deacetylase inhibitors that alleviate neutrophilic inflammation in acute lung injury and idiopathic pulmonary fibrosis via inhibiting leukotriene a4 hydrolase and blocking LTB4 biosynthesis

OBJECTIVE Leukotriene B4(LTB4)biosynthesis and subsequently neutrophilic inflammation may provide a potential strategy for the treatment of acute lung injury(ALI)or idiopathic pulmonary fibrosis(IPF).To provide a potential strategy for the treatment of ALI or IPF,we identified potent inhibitors of Leukotriene A4 hydrolase(LTA4H),a key enzyme in the biosynthesis of LTB4.METHODS In this study,we identified two known histone deacetylase(HDAC)inhibitors,suberanilohydroxamic acid(SAHA)and its analogue 4-(dimethylamino)-N-[7-(hydroxyamino)-7-oxoheptyl]benzamide(M344),as effective inhibitors of LTA4H using enzymatic assay,thermofluor assay,and X-ray crystallographic investigation.We next tested the effect of SAHA and M344 on endogenous LTB4 biosynthesis in neutrophils by ELISA and neutrophil migration by transwell migration assay.A murine experimental model of ALI was induced by lipopolysaccharide(LPS)inhalation.Histopathological analysis of lung tissue using H&E staining revealed the serious pulmonary damage caused by LPS treatment and the effect of the SAHA.We next examined m RNA and protein levels of pro-inflammatory cytokines in lung tissue and bronchoalveolar lavage fluid using q RT-PCR and ELISA to further investigate the underlying mechanisms of anti-inflammatory activities by SAHA.We also investigated the effects of SAHA and M344 on a murine experimental model of bleomycin(BLM)-induced IPF model.RESULTS The results of enzymatic assay and X-ray crystallography showed that both SAHA and M344 bind to LTA4H,significantly decrease LTB4 levels in neutrophil,and markedly diminish early neutrophilic inflammation in mouse models of ALI and IPF under a clinical safety dose.CONCLUSION Collectively,SAHA and M344 would provide promising agents with well-known clinical safety for potential treatment in patients with ALI and IPF via pharmacologically inhibiting LAT4H and blocking LTB4 biosynthesis.

Liver cold preservation induce lung surfactant changes and acute lung injury in rat liver transplantation

AIM： To investigate the relationship between donor liver cold preservation, lung surfactant （LS） changes and acute lung injury （ALI） after liver transplantation. METHODS： Liver transplantation models were estab- lished using male Wistar rats. Donor livers were pre- served in University of Wisconsin solution at 4 ℃ for different lengths of time. The effect of ammonium pyr- rolidinedithiocarbamate （PDTC） on ALI was also detect- ed. All samples were harvested after 3 h reperfusion.The severity of AU was evaluated by lung weight/body weight ratio, lung histopathological score, serum nitric oxide （NO） and endothelin （ET）-I levels, lung tumor necrosis factor （TNF）-α and interleukin （IL）-1β levels. Lung surfactants （LSs） were determined by micellar electrokinetic capillary chromatography. RESULTS： With extended donor liver cold preservation time （CPT）, lung histopathological scores, serum ET-i levels, lung weight/body weight ratio and the level of TNF-α and IL-1β in lung were increased significantly in the 180-min group compared with the sham group （3.16± 0.28 vs 1.12 ± 0.21, P 〈 0.001; 343.59±53.97 vs 141.53± 48.48, P 〈 0.001; 0.00687 ±0.00037 vs 0.00557 ±0.00056, P 〈 0.001; 17.5 ± 3.0 vs 1,3 ± 0.3, P 〈 0.001; 10.8± 2.3 vs 1.8 ± 0.4, P 〈 0.001）, but serum NO levels decreased remarkably （74.67 ± 10.01 vs 24.97 ± 3.18, P 〈 0.001）. The expression of lung phos- phatidylcholine （PC）, phosphatidylethanolamine （PE）, phosphatidylinositol （PI） and phosphatidylserine （PS） increased when CPT was 〈 120 rain, and decreased when CPT was 〉 180 min （PC： 1318.89 ± 54.79 vs 1011.18± 59.99, P 〈 0.001; PE： 1504.45± 119.96 vs 1340.80±76.39, P = 0.0019; PI： 201.23 ± 34.82 vs 185.88 ± 17.04, P = 0.2265; PS： 300.43±32.95 vs 286.55± 55.55, P = 0.5054）. All these ALI-associated indexes could be partially reversed by PDTC treatment.

Changes of pulmonary beta-adrenergic receptors and their relationship with membranous phospholipid metabolism in endotoxin-induced lung injury in rats

The changes of beta-adrenergic receptors (AARs) in lung tissue in endotoxin-induced acute lung injury was investigated with radioligand bindig assay in rats. The lipid fluidity and phospholipid content of the cellular membrane of lung tissue were measured with fluorescent polarization and high performance liquid chromatography respectively. The findings were as follows:1- Four hours after endotoxin injection, there was a 47% decrease of the maximal binding capacity of fyARsas compared with the control.2. Endotoxin was able to decrease the lipid fluidity and phospholipid content of the pulmonary cellular membrane markedly and at the same time. There was an elevated activity of phospholipase A2 in the pulmonary tissueThese findings suggest that the decrease of the binding capacity of &ARs results in a decrease of the PAR mediated functions, which plays a ro1e in the pathogensis of endotoxin-induced acute lung injury and the activation of phospholipase A2 which is an important factor to reduce the phospholipid content of cell membrane and subsequently to decrease its lipid fluidity, can result in a reduction of the lateral diffusion and rotatory movement of β-ARs and to decrease the chances of β-ARs to bind with the ligands.

Effects of pulmonary stretch reflex on lung injury in rabbits with acute respiratory distress syndrome

BACKGROUND： Pulmonary stretch reflex plays an important role in regulation of respiratorymovement. This study aimed to evaluate the effect of pulmonary stretch reflex on lung injury inrabbits with acute respiratory distress syndrome （ARDS）.METHODS： ARDS rabbits were given intratracheal infusion of hydrochloric acid and ventilatedwith neurally adjusted ventilatory assistance （NAVA） with a tidal volume （VT） of 6 mL/kg and theelectrical activity of diaphragm （EAdi）-determined positive end expiratory pressure. After isolation ofthe bilateral vagus nerve trunk, the rabbits were randomized into two groups： sham operation （SHAM）group （n=5） and bilateral vagotomy （VAG） group （n=5）. Gas exchange and respiratory mechanicswere detected at baseline, after lung injury and 1, 2, and 3 hours after ventilation respectively.Pulmonary permeability index, pathological changes and infl ammatory response were also measured.RESULTS： Compared with the SHAM group, PaO2/FiO2 in the VAG group decreased signifi cantly2 and 3 hours after ventilation （P〈0.05）. There was no significant difference in PaCO2 betweenthe SHAM and VAG groups （P〉0.05）, and the VAG group had a high VT, peak pressure （Ppeak）,and mean pressure （Pm） compared with the SHAM group 1, 2, 3 hours after ventilation （P〈0.05）.Compared to the SHAM group, dead space fraction （VD/VT） and respiratory system elastance （Ers）in the VAG group increased （P〈0.05） and static pulmonary compliance （Cst） decreased markedly（P〈0.05） after ventilation for 3 hours. Lung wet/dry weight ratio （W/D） （8.4±1.2 vs. 6.6±1.0）, lung injuryscore （6.3±1.8 vs. 3.8±1.3）, tumor necrosis factor-# （TNF-#） （779±372 pg/mL vs. 355±130 pg/mL）and interleukin-8 （IL-8） （169±21 pg/mL vs. 118±17 pg/mL） increased significantly in the VAG groupcompared with the SHAM group （P〈0.05）.CONCLUSION： Lung injury is aggravated after bilateral vagotomy, demonstrating thatpulmonary stretch refl ex may have protective effect on the lung.

Successful Extracorporeal Membranous Oxygenation with Possible Transfusion-Related Acute Lung Injury after Pulmonary Endarterectomy

Transfusion-related acute lung injury (TRALI) is characterized by acute severe hypoxemia with bilateral noncardiogenic pulmonary edema after transfusion of a plasma-containing blood component. In patients undergoing cardiac surgery, the incidence of TRALI is high;however, the detailed clinical course is unknown. Here, we report a case of life-threatening TRALI following pulmonary thrombectomy, which was successfully treated with extracorporeal membranous oxygenation (ECMO).

Effects of n-butanol extract of Rumex gmelini Turcz on the endotoxin-induced acute lung injury in mice

Objective: To study the effects of n-butanol extract of Rumex gmelini Turcz on the endotoxin-induced acute lung injury (ALI) in mice. Methods: Kunming mice were selected as experimental animals and randomly divided into normal control group (NC group), acute lung injury group (ALI group) and n-butanol extract of Rumex gmelini Turcz group (Rum group). ALI group and Rum group were established into ALI models by intraperitoneal injection of endotoxin, and Rum group were given intragastric administration of n-butanol extract of Rumex gmelini Turcz for intervention before model establishment. 12 h after endotoxin injection, the superior lobe of right lung was taken to determine the water content, and the inferior lobe of right lung was taken to determine the contents of AQPs molecules, inflammatory response molecules and oxidative stress molecules. Results: 12 h after endotoxin injection, the water content of lung tissue in Rum group was (6.82±0.97)%. After variance analysis, the water content of lung tissue in ALI group was significantly higher than that in NC group, AQP1 and AQP5 protein levels in lung tissue were significantly lower than those of NC group, AQP3 and AQP4 protein levels were not different from those of NC group, and MPO, NF-kB, TNF-α, HMGB1, IL-8, ROS, ATP, MDA, Bax and Caspase-3 protein levels were significantly higher than those of NC group;the water content of lung tissue in Rum group was significantly lower than that in ALI group, AQP1 and AQP5 protein levels in lung tissue were significantly higher than those of ALI group, AQP3 and AQP4 protein levels were not different from those of ALI group, and MPO, NF-kB, TNF-α, HMGB1, IL-8, ROS, ATP, MDA, Bax and Caspase-3 protein levels were significantly lower than those of ALI group. Conclusion:The n-butanol extract of Rumex gmelini Turcz reduce the pulmonary edema, inflammatory response, oxidative stress and apoptosis during the endotoxin-induced ALI in mice.

α_1-ANTITRYPSIN ATTENUATES ENDOTOXIN-INDUCED ACUTE LUNG INJURY IN RABBITS

Objective To investigate whether pretreatment with α 1-AT can attenuate acute lung injury (ALI) in rabbits induced with endotoxin. Methods Thirty-two New Zealand rabbits were randomly assigned to four groups(n=8):1.Infusion of endotoxin(Lipopolysaccharide,LPS 500μg/kg)without α 1-AT (group LPS).2.Infusion α 1-AT 120mg/kg at 15min before challenge with LPS(group LAV).3.Infusion of α 1-AT 120mg/kg(group AAT).4 Infusion of saline 4ml/kg as control (group NS).Arterial blood gases,peripheral leukocyte counts and airway pressure were recorded every 1h.Physiologic intrapulmonary shunting (Qs/Qt) was measured every 4h.After 8h the bloods were collected for measurement of plasma concentration and activity of α 1-AT.Then bronchoalveolar lavage fluid (BALF)was collected for measurement of concentrations of total protein (TP),interleukin-8(IL-8),tumor necrosis factor(TNF-α),the activities of elastase-like and α 1-AT,total phospholipids(TPL) and disaturated phosphatidylcholine (DSPC).In addition,the wet-to-dry lung weight ratio(W/D) was measured. Results After infusion of endotoxin,it was observed that PaO 2,peripheral luekocyte counts,total respiratory compliance progressively decreased and P peak and Qs/Qt increased comparing with the baseline values.In contrast to group NS,the increased plasma concentration but reduced activity of α 1-AT was found in group LPS.In the BALF,the activity of α 1-AT,TPL,DSPC/TPL were lower,but the concentrations of albumin,IL-8,TNF-α,and the activity of NE were higher.The ratio of W/D also increased.The pretreatment of α 1-AT attenuated the deterioration of oxygenation,the reduction of compliance and the deterioration of other physiological,biochemical parameters mentioned above. Conclusion Pretreatment with α 1-AT could attenuate endotoxin-induced lung injury in rabbits.Those beneficial effects of α 1-AT might be due in part to the inhibitory effect on neutrophil elastase.

Acute lung injury and acute respiratory distress syndrome： experimental and clinical investigations

Acute lung injury （ALl） or acute respiratory distress syndrome （ARDS） can be associated with various disorders. Recent investigation has involved clinical studies in collaboration with clinical investigators and pathologists on the pathogenetic mechanisms of ALl or ARDS caused by various disorders. This literature review includes a brief historical retrospective of ALI/ARDS, the neurogenic pulmonary edema due to head injury, the long-term experimental studies and clinical investigations from our laboratory, the detrimental role of NO, the risk factors, and the possible pathogenetic mechanisms as well as therapeutic regimen for ALI/ARDS.

The Role of Neutrophil Collagenase in Endotoxic Acute Lung Injury

The aim of this study was to determine the role of neutrophil collagenase in the pathogenesis of acute lung injury induced by endotoxin. 28 Sprague-Dawley were randomized into control group and LPS-enduced groups. Samples of left lung were obtained in 2 h (group L 1), 6 h (group L 2), 12 h (group L 3) after intravenous LPS. Immunohistochemsitry was employed for detection of expression of neutrophil collagenase. Pathological scores, lung wet/dry weight ratio and the number of neutrophils were measured. The results showed that the concentration of neutrophil collagenase in LPS-enduced groups (group L 1, L 2, L 3) were significantly higher than that of control group (P<0.01). Pathological scores, lung wet/dry weight ratio and the number of neutrophils in LPS-enduced groups (group L 1, L 2, L 3) were also significantly higher than that of control group (P<0.01). Moreover, among group L 1, L 2 and L 3, there were significant correlations in concentration of neutrophil collagenase and pathological scores, lung wet/dry weight ratio, the number of neutrophils (P<0.05). The present study showed that neutrophil collagenase play an important role in the pathogenesis and progress of endotoxic acute lung injury.

Acute lung injury mechanism and therapy induced by paraquat poisoning

Paraquat (PQ, methyl viologen) was widely used in agricultural production throughout the world in 1962 for its efficient herbicidal activity. PQ was also highly toxic drug. About 5 mL medicine including 20% paraquat was life-threatening that can cause poisoning. In 1966, some people died because of PQ poisoning. Most patients had acute respiratory distress syndrome after 2 wk, and 70% of them died due to the lack of effective detoxification drugs. Thus, it was particularly important to understand the pathogenesis of PQ poisoning and give some effective treatments. This article will review the toxicological mechanism and treatment on PQ poisoning of acute lung injury.

Effect of post recruitment maneuver ventilation by different tidal volume on lung vascular endothelial diastole function in rats with acute lung injury

BACKGROUND： This study aimed to observe the effect of recruitment maneuver （RM） and post-RM ventilation at different tidal volume on lung vascular diastole endothelial function in rats with acute lung injury （ALI）.METHODS： A ALl rat model was produced by intravenous infusion of lipopolysaccharide （6 mg/ kg）. Twenty-five rats were randomly divided into five groups： control group （n=5）, ALl group （n=5）, low tidal volume group （LV group, VT 6 mL/kg, n=5）, sustained inflation （SI） with low tidal volume group （SI＋LV group, VT 6 mL/kg, n=5）, and SI with moderate tidal volume group （SI＋MV group, VT 12 mL/ kg, n=5）. RM was performed with SI, airway pressure 30 cmH2O for 30 seconds, and positive end- expiratory pressure （PEEP） was set to 5 cmH2O. Lung tissue was taken after 5 hours of mechanical ventilation. Mean arterial blood pressure （MAP） was monitored during the experiment. Endothelin-1 （ET-1）, endothelial nitricoxide synthase （eNOS）, Ach-induced endothelium-dependent relaxation response of isolated pulmonary artery rings were determined at 5 hours. RESULTS：LPS increased ET-1 level, decreased the expression of eNOS in lung tissue, impaired the Ach-induced endothelium-dependent relaxation response in the pulmonary artery, without obvious effect on systemic hemodynamics. SI＋LV significantly reduced LPS-induced elevation of ET-1 level, increased the expression of eNOS, significantly improved endothelial dysfunction, and improved the dysfunction of endothelium-dependent relaxation in the pulmonary artery. CONCLUSIONS：RM with a high or low tidal volume ventilation could improve the lung vascular endothelial function of rats with acute lung injury, and RM with low tidal volume ventilation could lower significantly the injury of lung vascular endothelial diastole function in rats with acute lung injury.

Basic and clinical research progress in acute lung injury/acute respiratory distress syndrome

Acute lung injury(ALI)/acute respiratory distress syndrome(ARDS) is an acute progressive respiratory failure caused by severe infection, trauma, shock, poisoning, inhaled harmful gas, acute pancreatitis, and pathological obstetrics. ALI and ARDS demonstrate similar pathophysiological changes. The severe stage of ALI is defined as ARDS. At present, a significant progress has been achieved in the study of the pathogenesis and pathophysiology of ALI/ARDS. Whether or not ALI/ARDS patients can recover depends on the degree of lung injury, extra-pulmonary organ damage, original primary disease of a patient, and adequacy in supportive care. Conservative infusion strategies and protective lung ventilation reduce ARDS disability and mortality. In this study, the pathogenesis of ALI/ARDS, lung injury, molecular mechanisms of lung repair, and conservative infusion strategies and pulmonary protective ventilation are reviewed comprehensively.

Extracellular vesicles in the pathogenesis and treatment of acute lung injury

Acute lung injury(ALI)and acute respiratory distress syndrome(ARDS)are common life-threatening lung diseases associated with acute and severe inflammation.Both have high mortality rates,and despite decades of research on clinical ALI/ARDS,there are no effective therapeutic strategies.Disruption of alveolar-capillary barrier integrity or activation of inflammatory responses leads to lung inflammation and injury.Recently,studies on the role of extracellular vesicles(EVs)in regulating normal and pathophysiologic cell activities,including inflammation and injury responses,have attracted attention.Injured and dysfunctional cells often secrete EVs into serum or bronchoalveolar lavage fluid with altered cargoes,which can be used to diagnose and predict the development of ALI/ARDS.EVs secreted by mesenchymal stem cells can also attenuate inflammatory reactions associated with cell dysfunction and injury to preserve or restore cell function,and thereby promote cell proliferation and tissue regeneration.This review focuses on the roles of EVs in the pathogenesis of pulmonary inflammation,particularly ALI/ARDS.

GSN antibody pretreatment aggravates radiation-induced lung injury in mice

Radiation-induced lung injury is one of the main dose limiting factors for thoracic radiation therapy.Gelsolin(GSN) is a widespread,multifunctional regulator of cellular structure and metabolism.In this work,the roles of GSN in radiation-induced lung injury in Balb/c mice were studied.The GSN levels in plasma reduced progressively in 72 hours after irradiation,and then increased gradually.GSN contents in the bronchoalveolar lavage(BAL) fluid increased after thoracic irradiation,whereas mRNA levels of GSN in the lung tissue decreased significantly within 24 hours after irradiation and then increased again.Mice were intravenously injected with 50 ug GSN antibody 0.5 hour before 20 Gy of thoracic irradiation.GSN antibody pretreatment increased lung inflammation,protein concentration in the BAL fluid and leukocytes infiltration in the irradiated mice.The activities of superoxidase dismutase(SOD) in the plasma and the BAL fluid in irradiated mice injected with GSN antibody were less than that of control groups,whereas the levels of malondialdehyde(MDA)increased.These results suggest that pretreatment of GSN antibody may aggravate radiation-induced pneumonitis.

Mechanisms of pulmonary endothelial barrier dysfunction in acute lung injury and acute respiratory distress syndrome

Endothelial cells(ECs)form a semi-permeable barrier between the interior space of blood vessels and the un-derlying tissues.Pulmonary endothelial barrier integrity is maintained through coordinated cellular processes involving receptors,signaling molecules,junctional complexes,and protein-regulated cytoskeletal reorganiza-tion.In acute lung injury(ALI)or its more severe form acute respiratory distress syndrome(ARDS),the loss of endothelial barrier integrity secondary to endothelial dysfunction caused by severe pulmonary inflamma-tion and/or infection leads to pulmonary edema and hypoxemia.Pro-inflammatory agonists such as histamine,thrombin,bradykinin,interleukin 1𝛽,tumor necrosis factor𝛼,vascular endothelial growth factor,angiopoietin-2,and platelet-activating factor,as well as bacterial toxins and reactive oxygen species,cause dynamic changes in cytoskeletal structure,adherens junction disorganization,and detachment of vascular endothelial cadherin(VE-cadherin)from the actin cytoskeleton,leading to an increase in endothelial permeability.Endothelial interactions with leukocytes,platelets,and coagulation enhance the inflammatory response.Moreover,inflammatory infil-tration and the associated generation of pro-inflammatory cytokines during infection cause EC death,resulting in further compromise of the structural integrity of lung endothelial barrier.Despite the use of potent antibiotics and aggressive intensive care support,the mortality of ALI is still high,because the mechanisms of pulmonary EC barrier disruption are not fully understood.In this review,we summarized recent advances in the studies of endothelial cytoskeletal reorganization,inter-endothelial junctions,endothelial inflammation,EC death,and endothelial repair in ALI and ARDS,intending to shed some light on the potential diagnostic and therapeutic targets in the clinical management of the disease.

Effects of continuous tracheal gas insufflation during pressure limited ventilation on pulmonary surfactant in rabbits with acute lung injury

Background Pulmonary surfactant dysfunction may contribute to the development of ventilator induced lung injury （VILI）. Tracheal gas insuffiation （TGI） is a technique in which fresh gas is introduced into the trachea and augment ventilation by reducing the dead space of ventilatory system, reducing ventilatory pressures and tidal volume （VT） while maintaining constant partial arterial CO2 pressure （PaCO2）. We hypothesised that TGI limited peak inspiratory pressure （PIP） and VT and would minimize conventional mechanical ventilation （CMV） induced pulmonary surfactant dysfunction and thereby attenuate VILI in rabbits with acute lung injury （ALI）. Methods ALI was induced by intratracheal administration of lipopolysaccharide in anaesthetized, ventilated healthy adult rabbits randomly assigned to continuous TGI at 0.5 L/min （TGI group） or CMV group （n=8 for each group）, and subsequently ventilated with limited PIP and VT to maintain PaCO2 within 35 to 45 mmHg for 4 hours. Physiological dead space to VT ratio （VD/VT）, dynamic respiratory compliance （Cdyn） and partial arterial O2 pressure （PaO2） were monitored. After ventilation, lungs were analysed for total phospholipids （TPL）, total proteins （TP）, pulmonary surfactant small to large aggregates ratio （SA/LA） in bronchoalveolar lavage fluid （BALF） and for determination of alveolar volume density （Vv）, myeloperoxidase and interleukin （IL）-8. Results TGI resulted in significant （P〈0.05 or P〈0.01） decrease in PIP [（22.4±1.8） cmH20 vs （29.5±1.1） cmH2O], VT [（6.9±1.3） ml/kg vs （9.8±1.11） ml/kg], VD/VT [（32±5）% vs （46±2）%], TP [（109±22） mg/kg vs （187±25） mg/kg], SA/LA （2.5±0.4 vs 5.4±0.7）, myeloperoxidase [（6.2±0.5） U/g tissue vs （12.3±0.8） U/g tissue] and IL-8 [（987±106） ng/g tissue vs （24±3） mN/m] of BALF, and significant （P〈0.05） increase in Cdyn [（0.47±0.02） ml·cmH2O^-1·kg^-1 vs （0.31±0.02） ml·cmH2O^-1·kg^-1], PaO2 [（175±24） mmHg vs （135±26） mmHg], TPL/TP （52±8 vs 33±11） and Vv （0.65±0.05 vs 0.44±0.07） as compared with CMV. Conclusions In this animal model of ALI, TGI decreased ventilatory requirements （PIP, VT and VD/VT）, resulted in more favourable alveolar pulmonary surfactant composition and function and less severity of lung injury than CMV. TGI in combination with pressure limited ventilation may be a lung protective strategy for ALI.

Antithrombin-Ⅲ without concomitant heparin improves endotoxin-induced acute lung injury rats by inhibiting the activation of mitogen-activated protein kinase

Background Antithrombin-Ⅲ （AT-Ⅲ）, the major inhibitor of thrombin in plasma, also has anti-inflammation property and might have positive effect on sepsis. The present study aimed to investigate the effects of AT-Ⅲ on inflammatory reaction and pulmonary protection in endotoxin-induced acute lung injury （ALI） rat. Methods Sixty male Sprague-Dawley rats were randomly assigned equally to normal control group, ALl group, AT-Ⅲ treatment group, AT-Ⅲ＋heparin treatment group, and heparin treatment group. The pulmonary vascular permeability index （PVPI） was measured by single nuclide tracer technique. The activity of AT-Ⅲ in plasma was determined by the method of synthetic chromogenic substrata. Tumor necrosis factor-a （TNF-a） and interleukin-6 （IL-6） levels in serum were determined by enzyme-linked immunosorbent assay. The expressions of lung tissue mitogen-activated protein kinases （ERK1/2, P38 and JNK MAPK） were determined by Western blotting. Results Rats had significantly improved lung histopathology in the AT-Ⅲ treatment group and heparin treatment group compared with the ALl group, The PVPI of the ALl group was 0.38±0.04, significantly higher than that of the normal control group （0.20±0.02, P 〈0.01）, AT-Ⅲ treatment group （0.30±0.04, P 〈0.01） and heparin treatment group （0.28±0.04, P 〈0.01） respectively. There were no significant differences of PVPI in the ALl group and AT-Ⅲ＋heparin treatment group. The activity of AT-Ⅲ in plasma in the ALl group was （76±8）%, significantly lower than that of the normal control group （（96±11）%, P 〈0.05） and AT-Ⅲ treatment group （（105±17）%, P 〈0.05） respectively. The serum levels of TNF-α and I L-6 of the ALl group were （2.770±0.373） μg/L and （1.615±0.128） ng/ml respectively, significantly higher than those of the normal control group （0.506±0.093） μg/L and （0.233±0.047） ng/ml respectively, all P 〈0.01）, AT-Ⅲ treatment group （（1.774±0.218） pg/L and （1.140±0145） ng/ml respectively, all P 〈0.01） and heparin treatment group （（1.924±0.349） μg/L and （1.223±0.127） ng/ml respectively, all P 〈0.01）. The lung tissue levels of phospho-ERK1/2 and phospho-P38 MAPK expressions were markedly higher in the ALl group than in the normal control group, AT-Ⅲ treatment group and heparin treatment group respectively. Conclusions AT-Ⅲ without concomitant heparin inhibited the activation of ERK1/2 and P38 MAPK, down-regulated the levels of downstream cytokines TNF-a and IL-6, relieved endothelial permeability, and improved the ALl in endotoxin-induced rats. It might be helpful to administrate AT-Ⅲ alone, not with concomitant heparin, to those patients with ALl and sepsis.

Protective effects of α_1 -antitrypsin on acute lung injury in rabbits induced by endotoxin

Objective To investigate whether pretreatment with α1,-antitrypsin (AAT) can attenuate acute lung injury (ALI) in rabbits induced with endotoxin.Methods Thirty-two healthy adult New Zealand rabbits were anaesthetized, tracheotomized and mechanically ventilated. They were then randomly divided into four groups (n =8): (1) Infusion of Escherichia coli endotoxin [ Lipopolysaccharide (LPS) 500μg/kg ] without AAT (Group LPS). (2) Infusion of AAT 120 mg/kg at 15 minutes after LPS (Group LAV). (3) Infusion of AAT 120 mg/kg without endotoxin (Group AAT). (4) Infusion of saline 4 ml/kg as control (Group NS). Arterial blood gases, peripheral leukocyte counts and airway pressure were recorded every hour for eight hours. Physiologic intrapulmonary shunting (Qs/Qt) was measured every four hours. After eight hours, blood samples were collected for measurement of plasma concentration and activity of AAT. Then, the animals were sacrificed, and bronchoalveolar lavage fluid (BALF) was collected for measurement of concentrations of total protein (TP), interleukin-8 (IL-8), tumor necrosis factor (TNFa, the activities of NE and AAT, total phospholipids (TPL) and disaturated phosphatidylcholine (DSPC). In addition, the wet-to-dry lung weight ratio (W/D) was measured.Results The infusion of endotoxin induced decreases in arterial oxygen pressure (PaO2), peripheral leukocyte counts, total respiratory compliance (TLC) and the increases in peak pressure (Ppeak), Qs/ Qt compared with the baseline values ( P < 0. 05). The increased plasma concentration but reduced activity of AAT was also found in contrast to that in Group NS (P<0. 05). In the BALF, the activity of AAT, TPL, DSPC/TPL were lower than those in Group NS (P<0. 05), but the concentrations of albumin, IL-8, TNFα, the activity of NE and the ratio of W/D were higher than those in Group NS (P <0. 05). The pretreatment of AAT attenuated the deterioration of oxygenation, the reduction of compliance and the deterioration of other physiological and biochemical parameters mentioned above.Conclusion Pretreatment with AAT could attenuate endotoxin-induced lung injury in rabbits. Those beneficial effects of AAT might be due, in part, to reduction in the levels of mediators that could activate neutrophils, in addition to the direct inhibitory effect on neutrophil elastase.