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.

Establishment of Acute Lung Injury Model Induced by Intraperitoneal Injection of Lipopolysaccharide in Rats

The model of acute lung injury(ALI)was established by intraperitoneal administration,but there was no time-point observation and comparison.ALI model was established by intraperitoneal injection of lipopolysaccharide(LPS)at the concentration of 10 mg·kg^-1 (10 mg LPS dissolved in 1 mL normal saline to prepare 1 mL·kg^-1solution)in rats.The control group(CG)was intraperitoneally injected with saline of the same dose.In the LPS group,lung tissues were collected at 4,6,8,12 and 24 h after administration.Then,the morphology changes,the ratio of wet-to-dry weight(W/D),the expression of interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)proteins,the levels of malondialdehyde(MDA),the activities of superoxide dismutase(SOD),glutathione peroxidase(GSH)were measured.To verify the success of the model,the degrees of lung injury via Western blot,RT-PCR,ELISA and other techniques were detected at different time points,and the severe time of the ALI model established was deterimined by intraperitoneal administration,which provided a stable model basis for the study of the pathogenesis of ALI in the future.The results showed that the lung injury occurred in LPS group.W/D and lung pathological changes at 12 and 24 h of LPS group were significantly different from those in the CG.Compared with the CG,the expression of IL-1βand TNF-αproteins and the content of MDA in lung tissues of LPS group increased and most significant difference was found at 12 and 24 h(p<0.01).Compared with the CG,the activities of SOD and GSH in LPS 12 h group decreased significantly(p<0.01).In conclusion,inflammation and oxidative damage were the main causes of the ALI in rats.Lung injury was most obvious 12 h after intraperitoneal injection of 10 mg·kg^-1 LPS.

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.

Calycosin attenuates severe acute pancreatitis-associated acute lung injury by curtailing high mobility group box 1-induced inflammation

BACKGROUND Acute lung injury(ALI)is a common and life-threatening complication of severe acute pancreatitis(SAP).There are currently limited effective treatment options for SAP and associated ALI.Calycosin(Cal),a bioactive constituent extracted from the medicinal herb Radix Astragali exhibits potent anti-inflammatory properties,but its effect on SAP and associated ALI has yet to be determined.AIM To identify the roles of Cal in SAP-ALI and the underlying mechanism.METHODS SAP was induced via two intraperitoneal injections of L-arg(4 g/kg)and Cal(25 or 50 mg/kg)were injected 1 h prior to the first L-arg challenge.Mice were sacrificed 72 h after the induction of SAP and associated ALI was examined histologically and biochemically.An in vitro model of lipopolysaccharide(LPS)-induced ALI was established using A549 cells.Immunofluorescence analysis and western blot were evaluated in cells.Molecular docking analyses were conducted to examine the interaction of Cal with HMGB1.RESULTS Cal treatment substantially reduced the serum amylase levels and alleviated histopathological injury associated with SAP and ALI.Neutrophil infiltration and lung tissue levels of neutrophil mediator myeloperoxidase were reduced in line with protective effects of Cal against ALI in SAP.Cal treatment also attenuated the serum levels and mRNA expression of pro-inflammatory cytokines tumor necrosis factor-α,interleukin-6,IL-1β,HMGB1 and chemokine(CXC motif)ligand 1 in lung tissue.Immunofluorescence and western blot analyses showed that Cal treatment markedly suppressed the expression of HMGB1 and phosphorylated nuclear factor-kappa B(NF-κB)p65 in lung tissues and an in vitro model of LPSinduced ALI in A549 cells suggesting a role for HGMB1 in the pathogenesis of ALI.Furthermore,molecular docking analysis provided evidence for the direct interaction of Cal with HGMB1.CONCLUSION Cal protects mice against L-arg-induced SAP and associated ALI by attenuating local and systemic neutrophil infiltration and inflammatory response via inhibition of HGMB1 and the NF-κB signaling pathway.

Oxygenation,inflammatory response and lung injury during one lung ventilation in rabbits using inspired oxygen fraction of 0.6 vs.1.0

Maintaining adequate oxygenation during one-lung ventilation（OLV） requires high inspired oxygen fraction（FiO_2）.However,high FiO_2 also causes inflammatory response and lung injury.Therefore,it remains a great interest to clinicians and scientists to optimize the care of patients undergoing OLV.The aim of this study was to determine and compare oxygenation,inflammatory response and lung injury during OLV in rabbits using FiO_2 of 0.6 vs.1.0.After 30 minutes of two-lung ventilation（TLV） as baseline,30 rabbits were randomly assigned to three groups receiving mechanical ventilation for 3 hours：the sham group,receiving TLV with 0.6 FiO_2;the 1.0 FiO_2 group,receiving OLV with 1.0 FiO_2;the 0.6 FiO_2 group,receiving OLV with 0.6 FiO_2.Pulse oximetry was continuously monitored and arterial blood gas analysis was intermittently conducted.Histopathologic study of lung tissues was performed and inflammatory cytokines and the mRNA and protein of nuclear factor kappa B（NF-κB） p65 were determined.Three of the 10 rabbits in the 0.6 FiO_2 group suffered hypoxemia,defined by pulse oximetric saturation（SpO_2） less than 90%.Partial pressure of oxygen（PaO_2）,acute lung injury（ALI） score,myeloperoxidase（MPO）,tumor necrosis factor-a（TNF-α）,interleukin-6（IL-6）,mRNA and protein of NF-kB p65 were lower in the 0.6 FiO_2group than in the 1.0 FiO_2 group.In conclusion,during OLV,if FiO_2 of 0.6 can be tolerated,lung injury associated with high FiO_2 can be minimized.Further study is needed to validate this finding in human subjects.

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.

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.

Short term protective effect of digitoxin in sepsis-induced acute lung injury

Purpose:Digitoxin is a cardiac glycoside used in the treatment of heart failure.Inspired by its known antiinflammatory effect,this study aims to investigate the effect of digoxin in a sepsis model and to bring to light its effect and underlying mechanism in acute lung injury(ALI).Method:28 wistar albino rats were divided into 4 groups.Sepsis model is performed by the feces intraperitoneal-injection procedure(FIP).Results:TNF-a,CRP,IL-6,IL 1-Beta,lactic acid,and MDA values were significantly decreased in the FIP+digitoxin group compared to the FIP+Saline group.When the same groups were examined,histological improvements such as decrease in alveolar inflammation and decrease in septal thickening in the digitoxin group and thorax CT were found to be significantly higher in the Hounsfield unit digitoxin group compared to the Saline group.Conclusion:Digitoxin has shown biochemical improvement in sepsis with all known mechanisms of action,and healing effects in both computerized tomography and histology in the lung.

Lipopolysaccharide “Two-hit” Induced Refractory Hypoxemia Acute Respiratory Distress Model in Rats

To establish a stable and reliable model of refractory hypoxemia acute respiratory distress syndrome （ARDS） and examine its pathological mechanisms, a total of 144 healthy male Wistar rats were randomized into 4 groups： group Ⅰ （saline control group）, group Ⅱ （LPS intravenous ＂single-hit＂ group）, group Ⅲ （LPS intratracheal ＂single-hit＂ group） and Group IV （LPS ＂two-hit＂ group）. Rats were intravenously injected or intratracheally instilled with a large dose of LPS （10 mg/kg in 0.5 mL） to simulate a single attack of ARDS, or intraperitoneally injected with a small dose of LPS （1 mg/kg） followed by tracheal instillation with median dose of LPS （5 mg/kg） to establish a ＂two-hit＂ model. Rats in each group were monitored by arterial blood gas analysis and visual inspection for three consecutive days. Arterial blood gas values, lung wet/dry weight ratio and pathological pulmonary changes were analyzed to determine the effects of each ALI/ARDS model. Concentrations of TNF-α, IL-1 and IL-10 in the bronchoalveolar lavage fluid （BALF） and blood plasma were meastired by using enzyme-linked immunosorbent assays （ELISA）. Our resulsts showed that single LPS-stimulation, whether through intravenous injection or tracheal instillation, could only induce ALl and temporary hypoxemia in rats. A two-hit LPS stimulation induces prolonged hypoxemia and specific pulmonary injury in rats, and is therefore a more ideal approximation of ARDS in the animal model. The pathogenesis of LPS two-hit-induced ARDS is associated with an uncontrolled systemic inflammatory response and inflammatory injury. It is concluded that the rat ARDS model produced by our LPS two-hit method is more stable and reliable than previous models, and closer to the diagnostic criteria of ARDS, and better mimics the pathological process of ARDS.

Causes of failure in acute respiratory distress syndrome modeling and treatment in animal research and new approaches

Acute respiratory distress syndrome(ARDS) is a major cause of morbidity, death and cost in intensive careunits. Despite intensive research, pharmacotherapy has not passed the experimental stage and mortality rates are still high. Animal models provide a bridge between patients and the laboratory bench. Different animal models have been developed in order to mimic human ARDS, but they have limitations. The purpose of this review was to summarize the properties of the most commonly used experimental animal models mimicking the causes and pathology of human ARDS, the limitations of ARDS models, treatment failure and new therapeutic approaches.

A New Lung Mechanics Model and Its Evaluation with Clinical Data

Acute Respiratory Distress Syndrome (ARDS) is a major cause of morbidity and has a high rate of mortality. ARDS patients in the intensive care unit (ICU) require mechan-ical ventilation (MV) for breathing support, but inappropriate settings of MV can lead to ventilator induced lung injury (VILI). Those complications may be avoided by carefully optimizing ventilation parameters through model-based approaches. In this study we introduced a new model of lung mechanics (mNARX) which is a variation of the NARX model by Langdon et al. A multivariate process was undertaken to deter-mine the optimal parameters of the mNARX model and hence, the final structure of the model fit 25 patient data sets and successfully described all parts of the breathing cycle. The model was highly successful in predicting missing data and showed minimal error. Thus, this model can be used by the clinicians to find the optimal patient specific ventilator settings.

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.

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.

An Appreciation for the Rabbit Ladderlike Modeling of Radiation-induced Lung Injury with High-energy X-Ray

Background：To evaluate the utility of rabbit ladderlike model of radiation-induced lung injury （RILI） for the future investigation of computed tomography perfusion.Methods：A total of 72 New Zealand rabbits were randomly divided into two groups：36 rabbits in the test group were administered 25 Gy of single fractionated radiation to the whole lung of unilateral lung;36 rabbits in the control group were sham-radiated.All rabbits were subsequently sacrificed at 1,6,12,24,48,72 h,and 1,2,4,8,1 6,24 weeks after radiation,and then six specimens were extracted from the upper,middle and lower fields of the bilateral lungs.The pathological changes in these specimens were observed with light and electron microscopy;the expression of tumor necrosis factor-α （TNF-a） and transforming growth factor-βl （TGF-β1） in local lung tissue was detected by immunohistochemistry.Results：（1） Radiation-induced lung injury occurred in all rabbits in the test group.（2） Expression of TNF-a and TGF-β1 at 1 h and 48 h after radiation,demonstrated a statistically significant difference between the test and control groups （each P 〈 0.05）.（3） Evaluation by light microscopy demonstrated statistically significant differences between the two groups in the following parameters （each P 〈 0.05）：thickness of alveolar wall,density of pulmonary interstitium area （1 h after radiation）,number offibroblasts and fibrocytes in interstitium （24 h after radiation）.The test group metrics also correlated well with the time ofpostradiation.（4） Evaluation by electron microscopy demonstrated statistically significant differences in the relative amounts of collagen fibers at various time points postradiation in the test group （P 〈 0.005）,with no significant differences in the control group （P 〉 0.05）.At greater than 48 h postradiation the relative amount of collagen fibers in the test groups significantly differ from the control groups （each P 〈 0.05）,correlating well with the time postradiation （r =0.99318）.Conclusions：A consistent and reliable rabbit model of RILI can be generated in gradient using 25 Gy of high-energy X-ray,which can simulate the development and evolution of RILI.

Partial liquid ventilation decreases tissue and serum tumor necrosis factor-~ concentrations in acute lung injury model of immature piglet induced by oleic acid

Background Pediatric patients are susceptible to lung injury.Acute lung injury in children often results in high mortality.Partial liquid ventilation （PLV） has been shown to markedly improve oxygenation and reduce histologic evidence of injury in a number of lung injury models.This study was designed to examine the hypothesis that PLV would attenuate the production of local and systemic tumor necrosis factor （TNF）-α in an immature piglet model of acute lung injury induced by oleic acid （OA）.Methods Twelve Chinese immature piglets were induced acute lung injury by OA.The animals were randomly assigned to two groups of six animals,（1） conventional mechanical ventilation （MV） group and （2） PLV with 10 ml/kg FC-77 group.Results Compared with MV group,the PLV group had better cardiopulmonary variables （P 〈0.05）.These variables included heart rate,mean blood pressure,blood pH,partial pressure of arterial oxygen （PaO2）,PaO2/inspired O2 fraction （FiO2） and partial pressure of arterial carbon dioxide （PaCO2）.PLV reduced TNF-α levels both in plasma and tissue compared with MV group （P 〈0.05）.Conclusion PLV provides protective effects against TNF-a response in OA-induced acute lung injury in immature piglets.

15-deoxy-△12,14-prostaglandin J2 ameliorates endotoxin-induced acute lung injury in rats

Background A proinflammatory milieu emerging in the lung due to neutrophil accumulation and activation is a key in the pathogenesis of acute lung injury （ALI）.15-deoxy-△12,14-prostaglandin J2 （15d-PGJ2）,one of the terminal products of the cyclooxygenase-2 pathway,is known to be the endogenous ligand of peroxisome proliferator-activated receptor y （PPAR-y） with multiple physiological properties.Growing evidence indicates that 15d-PGJ2 has anti-inflammatory,antiproliferative,cytoprotective and pro-resolving effects.We investigated whether 15d-PGJ2 has a protective effect against endotoxin-induced acute lung injury in rats.Methods Twenty-four male Wistar rats were randomly assigned into four groups （n=6 per group）：sham＋vehicle group,sham＋15d-PGJ2 group,LPS＋vehicle group,and LPS＋15d-PGJ2 group.The rats were given either lipopolysaccharide （LPS,6 mg/kg intravenously） or saline,and pretreated with 15d-PGJ2 （0.3 mg/kg intravenously） or its vehicle （dimethyl sulphoxide） 30 minutes before LPS.Histological alterations,wet/dry weight （W/D） ratio and myeloperoxidase （MPO） activity as well as tumor necrosis factor （TNF）-α and cytokine-induced neutrophil chemoattractant-1 （CINC-1） levels were determined in lung tissues four hours after LPS injection.Immunohistochemical analysis for intercellular adhesion molecule-1 （ICAM-1） expression and Western blotting analysis for nuclear factor （NF）-κB p65 translocation and IκBα protein levels were also studied.Results 15d-PGJ2 pretreatment significantly attenuated LPS-induced lung injury,and reduced the increased W/D ratio,MPO activity,TNF-α,CINC-1 levels,and ICAM-1 expression in the lung.15d-PGJ2 also suppressed the nuclear NF-ΚB p65 translocation and increased cytosolic IKBα levels.Conclusions 15d-PGJ2 protects against endotoxin-induced acute lung injury,most likely through the reduction of proinflammatory protein levels during endotoxemia subsequent to the inhibition of NF-ΚB activation.

Study on the Establishment of a Rat Model for Transfusion-related Acute Lung Injury with Coronary Heart Disease and its Oxygen Balance

Objective:To establish a rat model of transfusion-related acute lung injury(TRALI)with coronary heart disease(CHD),and to analyze the safety of blood transfusion through oxygen balance.Methods:Forty-five 10-day-old male Wistar rats were purchased,and 35 of them were fed with high-fat diet to establish coronary heart disease rat models,and then 20 of them were selected to establish rat models of transfusion-related acute lung injury with coronary heart disease(model group,10 rats),positive acute lung injury group(positive group,5 rats)and negative acute lung injury group(negative group,5 rats),and the lung histomorphology,pathological score and wet/dry weight ratio were compared.Then,another 15 rats with coronary heart disease were selected and infused with mutant Hb,rHb1.1 and rHb2.0 with the same osmotic pressure through femoral vein catheterization,respectively,and were divided into mutant Hb group,rHb1.1 group and rHb2.0 group,with 5 rats in each group,and 5 healthy rats were combined as control group.The MAP,HR and blood gas values of mesenteric artery of rats were compared at 0,30,60 and 90 min after infusion.Results:(1)Rats in the model group and the positive group showed symptoms such as irregular and shallow breathing,increased oral and nasal secretions,and audible wheezing,which were consistent with the symptoms of acute lung injury.Comparison of lung histological score and lung tissue wet/dry ratio in three groups:There was no significant difference in lung histological score and lung tissue wet/dry ratio(P>0.05),but they were higher than those in the negative group(P<0.05).(2)During hemoglobin infusion,the MAP of mutant Hb group,rHb1.1 group and rHb2.0 group was higher than that of the control group,while the pH and PaCO2were lower than those of the control group(P<0.05),and there was no significant difference in QSMA(P>0.05).In the mutant Hb group,MAP returned to normal at 30-60 min after infusion(P>0.05),but MAP increased again at 90 min after infusion(P<0.05),and QSMA increased significantly at 60 min after transfusion(P<0.05).The pH value was lower than the normal value and the PaCO2was higher than the normal value within 90 min of infusion(P<0.05),and the HCO3-level returned to normal after 30 min of infusion(P>0.05).In rHb 1.1 group,MAP returned to normal,QSMA remained at normal level(P>0.05),and pH,PaCO2and HCO3-returned to normal after 60 min of infusion(P>0.05);In rHb 2.0 group,the levels of MAP,pH,PaCO2and HCO3-returned to normal after 30 min of infusion(P>0.05),and QSMA remained normal during infusion(P>0.05).Conclusion:The rat model of transfusion-relatted acute lung injury with coronary heart disease can be successfully established by injecting LPS into the rat model of coronary heart disease,and the infusion of recombinant hemoglobin can improve the balance of blood supply in rats,in which the infusion of rHb2.0 can better correct the metabolic acidosis.

输注异基因耐受性DC产生的外囊泡体引发输血相关急性肺损伤风险的研究

目的探讨利用耐受性的树突状细胞(dendritic cell,DC)分泌的细胞外囊泡(extracellular vesicles,EVs)干预感染后输血相关急性肺损伤(transfusion-related acute lung injury,TRALI)策略的风险。方法体外诱导小鼠骨髓来源的DC细胞用雷帕霉素处理诱导成耐受性DC,收集其培养上清,通过梯度离心法收获EVs。利用LPS和抗H2Kd抗体诱导Balb/c小鼠为TRALI疾病模型,并尝试用同基因的雷帕霉素-DC或者异基因的雷帕霉素-DC分泌的EV对TRALI小鼠进行干预,观察并记录发病小鼠的一系列数据。结果与TRALI发病组相比,使用雷帕霉素处理后的同基因耐受性DC对TRALI发病小鼠进行干预后,小鼠的死亡率显著下降。当用异基因耐受性DC(雷帕霉素处理后)产生的EVs进行干预组的肺湿/干比率、胸腔积液和体温与仅用LPS和H2Kd抗体处理组小鼠没有显著性差异。来源于耐受性细胞异基因EVs与LPS联合后不诱发小鼠的TRALI,但是EVs干预后的死亡率与注射浓度呈正相关。结论雷帕霉素处理后的同基因DC对感染后TRALI具有保护作用,并且该耐受细胞的异基因细胞外囊泡联合LPS后本身并不引起呼吸窘迫现象,当这种异基因外囊泡体输注联合抗白细胞抗体时,却加重了TRALI的死亡风险。本研究数据提示,异基因外囊泡体的应用与输血同时进行时,也许可能会加重TRALI死亡风险。

建立急性高原低氧肺组织损伤雄性大鼠模型并探讨高原低氧肺组织损伤机制

目的摸索相关参数建立急性高原低氧肺组织损伤雄性大鼠模型并探讨高原低氧肺组织损伤机制。方法1.建立急性高原低氧肺组织损伤雄性大鼠模型的方法:采用随机数字表法将雄性大鼠分为5组,即空白对照组,高原低氧6h组、24h组、48h组、72h组,适应性喂养7 d后进低压氧舱(模拟海拔7000 m),以肺组织纹理模糊、肺泡壁变厚、肺泡间隔增宽判断造模成功。2.探讨高原低氧肺损伤机制的方法:分别比较各组大鼠动脉血血气分析(ABG)结果、肺组织血管紧张素II(Ang II)含量、肺组织内皮素1(ET-1)含量和肺组织血管紧张素转化酶(ACE)m RNA的表达情况及肺组织超微结构,并作相关性分析。结果1.各组雄性大鼠ABG相关指标的变化:与对照组比较,高原低氧6 h、24 h、48 h、72 h组氧分压(PaO_(2))、动脉血氧饱合度(SaO_(2))、二氧化碳分压(PaCO_(2))和酸碱度(p H)值均下降,在一定时间范围内缺氧时间越长下降越明显(P<0.05)。2.各组雄性大鼠肺组织形态学的变化:与对照组比较,光镜下可见高原低氧各组出现不同程度的肺纹理模糊、肺泡壁增厚、肺泡间隔增宽;随着缺氧时间延长,肺组织损伤逐渐加重。3.各组雄性大鼠肺组织AngⅡ、ET-1含量变化:与对照组比较,高原低氧各组大鼠肺组织AngⅡ、ET-1含量明显升高(P<0.01),在一定时间范围内随缺氧时间延长而增加,72 h组达到高峰。4.各组雄性大鼠肺组织ACE m RNA表达比较:与对照组比较,高原低氧各组大鼠肺组织ACE m RNA表达均上调,6h组升高显著,72h组达到峰值(P<0.01)。结论利用低压氧舱模拟海拔7000 m环境,可以有效建立大鼠肺组织损伤模型;高原低氧肺损伤机制可能与ET-1、AngⅡ及ACE m RNA的表达水平上调,肾素-血管紧张素系统(RAS)失衡有关。