Apocynin attenuates lipopolysaccharide-induced lung injury in an isolated and perfused rat lung model

Apocynin (Apo) suppresses the generation of reactive oxygen species that are implicated in lipopolysaccharide (LPS)-induced lung injury (LPSLI). We thus hypothesized that Apo may attenuate LPSLI. In addition, we explored the cellular and molecular mechanisms of Apo treatment in LPSLI. Lipopolysaccharide-induced lung injury was induced by intratracheal instillation of 10 mg/kg LPS in isolated and perfused rat lung model. Apocynin was administered in the perfusate at 15 min before LPS was administered. Hemodynamics, lung injury indices, inflammatory responses, and activation of apoptotic pathways were assessed. There was an increase in lung vascular permeability associated with lung weight gain after LPS exposure. The levels of interleukin 1β (IL-1β), tumor necrosis factor α (TNF-α), macrophage inflammatory protein 2, H2O2, and albumin increased in the bronchoalveolar lavage fluid. Adhesion molecule of neutrophil (CD31) was upregulated. The expression of TNF-α, IL-1β, glutathione, myeloperoxidase, JNK, P38, caspase 3, p-AKT, and plasminogen activator inhibitor 1 in lung tissue was greater in the LPS groups when compared with the control group. Upregulation and activation of nuclear factor κB occurred along with increased histopathologic lung injury score in LPSLI. The Apo attenuated these inflammatory responses including the levels of CD31, H2O2, TNF-α, IL-1β, myeloperoxidase, P38, and nuclear factor κB along with downregulation of apoptosis as reflected by caspase 3 and p-AKT. In addition, Apo attenuated the increase in lung weight, bronchoalveolar lavage fluid albumin content, and the histopathologic lung injury score. In conclusion, LPSLI is associated with increased inflammatory responses, apoptosis, and coagulation. The administration of Apo attenuates LPSLI through downregulation of the inflammatory responses and apoptosis.     

Inhaled milrinone attenuates experimental acute lung injury

Purpose  To test whether inhalation of the phosphodiesterase 3 inhibitor milrinone may attenuate experimental acute lung injury (ALI). Methods  In rats, ALI was induced by infusion of oleic acid (OA). After 30 min, milrinone was inhaled either as single dose, or repeatedly in 30 min intervals. In mice, ALI was induced by intratracheal instillation of hydrochloric acid, followed by a single milrinone inhalation. Results  Four hours after OA infusion, ALI was evident as lung inflammation, protein-rich edema and hypoxemia. A single inhalation of milrinone attenuated the increase in lung wet-to-dry weight ratio and myeloperoxidase activity, and reduced protein concentration, neutrophil counts and TNF-α levels in bronchoalveolar lavage. This effect was further pronounced when milrinone was repeatedly inhaled. In mice with acid-induced ALI, milrinone attenuated hypoxemia and prevented the increase in lung myeloperoxidase activity. Conclusions  Inhalation of aerosolized milrinone may present a novel therapeutic strategy for the treatment of ALI.     

Heparanase pretreatment attenuates endotoxin-induced acute lung injury in rats

A central event of systemic inflammation and septic organ injury is infiltration of tissues with polymorphonuclear neutrophils, likely modulated by the integrity of the extracellular matrix underlying the vascular endothelium. In the present study, the effect of matrix-modifying endoglycosidase (heparanase) on endotoxin (LPS)-induced inflammatory lung injury was investigated in rats. Animals were treated with heparanase or LPS or pretreated with heparanase before LPS injection, and acute lung injury was verified histologically and characterized by analysis of bronchoalveolar lavage fluids. Pretreatment with heparanase attenuated the mortality of animals and preserved the histological structure of the lungs. Furthermore, polymorphonuclear neutrophil accumulation and activation, analyzed by myeloperoxidase release and reactive oxygen species production associated with lung injury, were significantly reduced upon heparanase pretreatment. In addition, heparanase pretreatment elevated the IL-10 levels in the pulmonary compartment. Moreover, results from in vitro experiments have identified monocyte-derived IL-10 as an important mediator used by heparanase to suppress inflammatory reactions. The protective effect of heparanase may indicate a novel therapeutic strategy for sepsis.     

Insulin attenuates endotoxin-induced acute lung injury in conscious rats

OBJECTIVES: To investigate the effects of insulin on the acute lung injury induced by lipopolysaccharide using a conscious rat model. DESIGN: Prospective, randomized, controlled animal study. SETTING: University research laboratory. SUBJECTS: A total of 190 adult male Sprague-Dawley rats weighing 250-300 g. INTERVENTIONS: Endotoxemia was induced by intravenous infusion of lipopolysaccharide. Lipopolysaccharide at various doses (0, 1, 5, 10, 20, and 30 mg/kg, n=10 for each dose) was administered intravenously in 20 mins. Insulin infusion at doses of 0.5, 1, and 5 microU/kg/min was given 5 mins before lipopolysaccharide administration. Plasma glucose was clamped at 90-110 mg/dL by infusion of 10-80% glucose solution. Insulin and glucose infusion (0.01 mL/min) was started 5 mins before lipopolysaccharide and continued for 120 mins. The rats received a total of 60, 120, and 600 microU/kg insulin as well as 0.12, 0.36, and 0.96 g of glucose in respective groups. The animals were then observed for 4 hrs. MEASUREMENTS AND MAIN RESULTS: The extent of acute lung injury was evaluated by lung weight/body weight ratio, lung weight gain, protein concentration in bronchoalveolar lavage, and exhaled nitric oxide. We also measured plasma nitrate/nitrite and methyl guanidine. In addition, histopathologic changes of the lung were examined. Lipopolysaccharide caused systemic hypotension and severe acute lung injury with increases in plasma nitrate/nitrite and methyl guanidine. Pretreatment with insulin infusion at doses of 0.5, 1, and 5 microU/kg/min mitigated or prevented systemic hypotension and the development of acute lung injury, depending on the dose. Insulin also attenuated the lipopolysaccharide-induced increases in nitrate/nitrite and methyl guanidine. CONCLUSIONS: Insulin is effective in reducing or preventing the lipopolysaccharide-induced increases in plasma nitrate/nitrite and methyl guanidine and the occurrence of acute lung injury.     

Levobupivacaine attenuates lipopolysaccharide‐induced acute lung injury

Levobupivacaine (LB), a kind of local anesthetic, possesses anti‐inflammatory properties. High‐mobility group box 1 (HMGB1), a nuclear DNA‐binding protein, plays a key role in the development of acute lung injury (ALI). The aim of this study was to investigate whether LB attenuates ALI by the inhibition of HMGB1 expression and to investigate the molecular mechanisms. ALI in male rats was induced by an intratracheal instillation of LPS (5 mg/kg), and male rats received mini‐osmotic pumps containing LB 30 min after LPS exposure. A549 alveolar epithelial cells were incubated with LPS in the presence or absence of LB. An enzyme‐linked immunosorbent assay was used to detect the levels of inflammatory cytokines. Western blotting was used to detect the changes in the expression of toll‐like receptor 2/4 (TLR2/4) and the activation of NF‐κB. The results showed that LB significantly protected animals from LPS‐induced ALI as evidenced by a decrease in the ratio of lung wet to dry weight, total cells, neutrophils, macrophages, and myeloperoxidase activity, associated with a reduced lung histological damage. We also found that LB post‐treatment markedly inhibited the release of HMGB1 and other pro‐inflammatory cytokines. Furthermore, LB significantly inhibited LPS‐induced TLR2/4 protein overexpression and NF‐κB activation in the lung tissues and in LPS‐stimulated A549 alveolar epithelial cells in vitro. These data indicate that LB attenuated LPS‐induced ALI by the inhibition of HMGB1 expression in rats. These benefits were associated with the inhibition of TLR2/4‐NF‐κB pathway by LB.     

Alpinumisoflavone attenuates lipopolysaccharide-induced acute lung injury by regulating the effects of anti-oxidation and anti-inflammation both in vitro and in vivo

Alpinumisoflavone (AIF) is a plant-derived pyranoisoflavone that exhibits a number of pharmacological activities, but the protective effects of AIF against pulmonary inflammation are still unknown. This study aimed to investigate the anti-inflammatory effects and possible molecular mechanisms of AIF in both lipopolysaccharide (LPS)-stimulated macrophages and mice. The results revealed that AIF dramatically suppressed the production of pro-inflammatory mediators [including tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, IL-17, intercellular adhesion molecule-1 (ICAM-1), and nitric oxide (NO)] and increased the levels of anti-oxidative enzymes [including catalase (CAT), heme oxygenase-1 (HO-1), glutathione peroxidase (GPx), and superoxide dismutase (SOD)] both in vitro and in vivo. Additionally, pre-treatment with AIF could not only significantly prevent histopathological changes and neutrophil infiltration but also decreased the expression levels of nuclear factor-kappa B (NF-κB), mitogen-activated protein kinases (MAPKs), and the nucleotide-binding domain-like receptor protein 3 (NLRP3) inflammasome, as well as IL-17 production in LPS-induced lung tissues. The anti-inflammatory effects of AIF were mediated by up-regulating anti-oxidative enzymes and suppressing the NF-κB, MAPK, NLRP3 inflammasome and IL-17 signaling pathways. This is the first study to reveal that AIF has a protective effect against LPS-induced lung injury in mice.

The present study demonstrated that alpinumisoflavone exerts the significant effects of anti-inflammatory and anti-oxidative in both LPS-induced RAW264.7 macrophages and a mouse model of acute lung injury.     

槲皮素对内毒素急性肺损伤的保护作用

目的　探讨槲皮素 (quercetin)对内毒素急性肺损伤 (ALI)的保护作用。方法　 2 4只SD大鼠 ,随机分成ALI模型组、槲皮素干预组、正常对照组 (n =8只 )。各组大鼠均于注射LPS或生理盐水 6h后测定PaO2 、pH值、PaCO2 ,血清TNF α、IL 8、P 选择素浓度和肺组织匀浆髓过氧化物酶 (MPO)含量及TNF α、IL 8、P 选择素浓度 ;观察肺病理改变、肺湿 /干重比 (W /D)。结果　与ALI模型组比较 ,槲皮素干预组的肺水肿病理改变明显减轻 ,PaO2 改善 ,MPO、P 选择素及TNF α、IL 8降低 (P <0 0 1)。结论　槲皮素能改善ALI大鼠的气体交换功能 ,抑制炎性介质的释放 ,对内毒素诱导的ALI有保护作用     

参附注射液对大鼠内毒素性急性肺损伤的保护作用

目的:观察参附注射液(SF)对大鼠内毒素性急性肺损伤(ALI)时肺组织湿/干重比(W/D)等的影响,探讨其对ALI是否具有保护作用.方法:采用大鼠气管内滴注内毒素诱导ALI模型,30只大鼠随机分为NS组、LPS组、SF组,每组10只.观察每组肺组织W/D、肺泡灌洗液中性粒细胞比、蛋白含量、血清NO、肺组织丙二醛(MDA)含量及比较动脉血气分析的结果.同时观察肺组织病理形态学改变.结果:与NS组比较,LPS组、SF组的肺组织W/D、肺泡灌洗液中性粒细胞比、蛋白含量、肺组织MDA和血清NO显著增加,而PaO2和HCO3-明显降低(P<0.01);与LPS组比较,SF组以上指标显著降低而PaO2和HCO3-明显升高(P<0.05或P<0.01).病理学检查显示SF组肺组织损伤程度较LPS组明显减轻.结论:SF对内毒素性ALI具有防治作用.     

鼠尾草酚对脂多糖诱导的小鼠急性肺损伤的作用及机制分析

目的 探讨鼠尾草酚在脂多糖(LPS)诱导的小鼠急性肺损伤(ALI)中的作用及其分子机制.方法 将40只周龄10～ 12周的雄性C57BL/6J小鼠随机分为对照组、鼠尾草酚组、ALI组和治疗组(ALI+鼠尾草酚),每组10只.鼠尾草酚组和治疗组于LPS注射前1周给予鼠尾草酚20 mg/(kg·d)灌胃,持续7d.ALI组和治疗组通过单次腹腔注射LPS (10 mg/kg)的方式构建小鼠ALI模型,对照组和鼠尾草酚组则注射等剂量生理盐水.注射LPS 12 h后,取小鼠主动脉血和肺组织,检测各组小鼠的动脉血氧分压[pa(O2)]、动脉血二氧化碳分压[pa(CO2)]、血清乳酸脱氢酶(LDH),记录肺湿干质量比值,HE染色观察各组小鼠肺组织损伤状况.采用免疫印迹法检测各组小鼠肺组织中铁死亡标志蛋白前列腺素内过氧化物合酶2(PTGS2)蛋白和谷胱甘肽过氧化物酶4(GPX4)蛋白的表达水平.检测小鼠肺组织中核转录因子红系2相关因子2(Nrf2)/血红素氧合酶-1(HO-1)信号通路相关蛋白的表达.结果 与对照组相比,ALI组小鼠肺组织出现明显肺水肿、炎症细胞和红细胞浸润等损伤特征,肺湿干质量比值、气道压、pa(CO2)升高,pa(O2)降低,肺组织中PTSG2蛋白表达升高、GPX4蛋白降低,Nrf2、HO-1蛋白表达降低,差异均有统计学意义(P＜0.05);与ALI组相比,治疗组小鼠肺组织损伤减轻,肺湿干质量比值降低,pa(O2)升高,pa(CO2)降低,肺组织中PTSG2蛋白表达降低、GPX4蛋白升高,Nrf2、HO-1蛋白表达升高,差异均有统计学意义(P＜0.05).结论 鼠尾草酚具有减轻小鼠ALI的作用,其可能通过调控Nrf2/HO-1抑制铁死亡而发挥肺保护作用.     

丙戊酸钠对脂多糖诱导大鼠急性肺损伤的保护作用

目的 研究丙戊酸钠(valproic acid,VPA)对脂多糖(lipopolysaccharide,LPS)诱导的大鼠急性肺损伤的影响.方法 实验地点在武汉协和医院中心实验室,通过股静脉注射LPS复制大鼠急性肺损伤模型,观察光镜下肺组织病理学改变、血清炎性因子和肺部炎性反应判定模型是否成功.依据干预药物的不同确定实验分组:股静脉给予5mL/kg生理盐水为对照组(NS组),股静脉给予LPS 10 mg/kg为模型组(LPS组),模型成功后股静脉给予VPA 300mg/kg治疗为治疗组(LPS+VPA组).注射LPS或NS后6 h处死动物,血气分析观察动脉血氧分压(PaO2)、肺泡气-动脉血氧分压差(A-aDO2)、乳酸(Lac),检测肺组织干湿重比(W/D),髓过氧化物酶(MPO)活性,肺泡灌洗液(BALF)中白蛋白质量浓度,用ELISA法检测6 h血清中TNF-α和IL-1β的含量,HE染色光镜下观察肺组织病理学变化.计量资料以均数±标准差(-x±s)表示,应用SPSS 13.0统计软件行单因素方差分析.结果 LPS组PaO2(mmHg)(81.50±3.24)较NS组(106.40±4.50)降低,A-aDO2(mmHg),Lac[(19.70±2.21),(3.63±0.22)]较NS组[(6.30±1.70),(1.21±0.19)]升高,W/D,MPO活性(μ/g),BALF中白蛋白质量浓度(pg/mL)分别为[(6.52±0.30),(7.25±0.49),(2.940±0.047)]较NS组[(4.38±0.17),(1.76±0.31),(0.099±0.077)]升高,血清中TNF-α和IL-1β的质量浓度(pg/ml)分别为(3325±284),(1950±222)较NS组(90±12),(50±11)显著升高,差异具有统计学意义(P＜0.05),LPS组肺组织出现病理学改变;与LPS组比较,LPS+VPA组上述指标除PaO2(mmHg)(94.50±4.38)上升外,其余指标均降至[(13.50±4.77),(2.13±1.02),(5.33±0.12),(4.38±0.42),(1.260±0.039),(2410±320),(1220±162)],差异具有统计学意义(P＜0.05),LPS+VPA组肺组织病理学改变明显减轻.结论 丙戊酸钠对脂多糖诱导的大鼠急性肺损伤有一定保护作用.

Abstract：

Objective To investigate the effects of valproic acid (VPA) on acute lung injury induced by Lipopolysaccharide in rats. Method The rat model of acute lung injury was made by intravenous injection of lipopolysaccharide (LPS). The pathological changes of lung were observed under light microscope and inflammatory cytokines in serum detected by using ELISA to judge whether the model was successfully done or not. All rats were divided into three groups as per the different intervention agents employed. Rats in control group were treated with intravenous injection of NS in dose of 5 ml/kg, rats in LPS group were exposed to LPS with dosage of 10 mg/kg and model rats in LPS + VPA group were treated with VPA in dose of 300 mg/kg. The rats were sacrificed 6 h after LPS or NS administration. The blood PaO2 ,A-aDO2 and blood lactic acid (Lac) were measured, the lungs were removed for observing the histopathological changes and determination of wet/dry lung weight (W/D) ratio and myeloperoxidase (MPO) activity as well as albumin concentration in broncho-alveolar lavage fluid (BALF) . Seurm was collected to determine the concentrations of tumor necrosis factor-a (TNF-α) and interleukin-1β( IL-1 β) by using LISA 6 h later. All data were presented in ((x)±s). One-way ANOVA was used for comparing differences between groups. Results Compared with acute lung injury group, the blood PaO2 (94. 50 ± 4.38 ) in rats of LPS + VPA group was higher, whereas A-aDO2 ( 13.50 ± 4.77 ) and blood lac( 2.13 ± 1. 02 ) in LPS + VPA group were lower. VPA significantly lowered W/D (5.33 ±0. 12) ratio and MPO activity (4.38 ±0. 42) in the lung. Albumin concentration ( 1. 260 ± 0. 039 ) in BALF, and the levels of TN F-α( 2 410 ±320 )and IL-1β( 1 220 ± 162 )in serum were lower in LPS + VPA group. The histological changes of lung injury were lessened by VPA. Conclusions Valproic acid has protective effects against lipopolysaccharide-induced acute lung injury in rats.     

脂多糖致大鼠急性肺损伤模型取材时间选择

目的 探讨制备大鼠急性肺损伤模型过程中取材时间的选择.方法 30只成年雄性SD大鼠,随机分为生理盐水对照组(对照组)6只和脂多糖组24只.脂多糖组大鼠尾静脉注射浓度为10 mg/kg脂多糖1 mL建立急性肺损伤模型,对照组大鼠尾静脉注射1 mL生理盐水.对照组和脂多糖组于注药后1、3、6、12 h各取大鼠6只,检测肺组织湿、干质量比,采用光镜观察肺组织病理形态学,采用免疫组织化学法检测肺组织白细胞介素-6和血管内皮生长因子表达情况.结果 注射脂多糖1h后,脂多糖组光镜下可见肺间质水肿和炎症细胞浸润;脂多糖组1、3、6、12h时肺组织湿/干质量比(5.57±0.55、5.81±0.81、6.11±0.68、5.84±0,52)、肺损伤评分((1.17±0.41)、(2.33±0.52)、(3.50±0.55)、(2.83±0.75)分)、肺组织白细胞介素-6((31.33±6.95)、(78.33±7.53)、(95.17±10.93)、(72.00±10.30)ng/L)和血管内皮生长因子((228.17±17.30)、(284.33±18.74)、(384.50±29.22)、(316.33±26.80)ng/L)水平明显高于对照组((5.19±0.98)、(0.00±0.00)分、(9.00±3.85)ng/L、(197.50±15.18)ng/L)(P＜0.05),其中6h时明显高于1、3、12 h时;3、12 h时高于1h时(P＜0.05).结论 尾静脉注射10 mg/kg脂多糖在6h时可成功复制大鼠急性肺损伤模型.     

L-arginine attenuates acute lung injury after smoke inhalation and burn injury in sheep

Thermal injury results in reduced plasma levels of arginine (Arg). With reduced Arg availability, NOS produces superoxide instead of NO. We hypothesized that Arg supplementation after burn and smoke inhalation (B + S) injury would attenuate the acute insult to the lungs and, thus, protect pulmonary function. Seventeen Suffolk ewes (n = 17) were randomly divided into three groups: (1) sham injury group (n = 6), (2) B + S injury plus saline treatment (n = 6), and (3) B + S injury plus L-ARG infusion at 57 mg.kg(-1).h(-1) (n = 5). Burn and smoke inhalation injury was induced by standardized procedures, including a 40% area full thickness flame burn combined with 48 breaths of smoke from burning cottons. All animals were immediately resuscitated by Ringer solution and supported by mechanical ventilation for 48 h, during which various variables of pulmonary function were monitored. The results demonstrated that Arg treatment attenuated the decline of plasma Arg concentration after B + S injury. A higher plasma Arg concentration was associated with a less decline in Pao2/Fio2 ratio and a reduced extent of airway obstruction after B + S injury. Histopathological examinations also indicated a remarkably reduced histopathological scores associated with B + S injury. Nitrotyrosine stain in lung tissue was positive after B + S injury, but was significantly reduced in the group with Arg. Therefore, L-Arg supplementation improved gas exchange and pulmonary function in ovine after B + S injury via its, at least in part, effect on reduction of oxidative stress through the peroxynitrite pathway.     

Therapeutic hypothermia attenuates acute lung injury in paraquat intoxication in rats

Aim of the study

Paraquat intoxication induces acute lung injury and numerous fatalities have been reported. The mechanism of toxic effect of paraquat is oxidative injury and inflammation. Therapeutic hypothermia has been known to have antioxidant and anti-inflammatory effects. This study was designed to evaluate the effect of therapeutic hypothermia on paraquat intoxication.

Methods

Male Sprague-Dawley rats were given 50 mg/kg of paraquat intraperitoneally and divided into the normothermia (36-38 °C) group and the hypothermia (30-32 °C) group after 1 h of paraquat administration. The hypothermia group underwent 2 h of hypothermia followed by 2 h of rewarming. In the survival study, mortality was observed for 24 h after paraquat administration. An in the second experiment, lung tissues and plasma were harvested at 6 h after paraquat administration.

Results

The 12 h survival rate was significantly higher in the hypothermia group than in the normothermia group (100% vs. 50%, p < 0.05), but survival rates for 24 h were not different. Acute lung injury score was lower in the hypothermia group than in the normothermia group (p < 0.05). Thmalondialdehyde contents of lung tissues, plasma interleukin-6 and nitrite/nitrate concentrations were significantly decreased in the HT group compared to the NT group (p < 0.05).

Conclusion

Therapeutic hypothermia delayed early mortality and attenuated acute lung injury in paraquat intoxication.     

Neutralization of osteopontin attenuates neutrophil migration in sepsis-induced acute lung injury

IntroductionSepsis refers to severe systemic inflammation leading to acute lung injury (ALI) and death. Introducing novel therapies can reduce the mortality in ALI. Osteopontin (OPN), a secretory glycoprotein produced by immune reactive cells, plays a deleterious role in various inflammatory diseases. However, its role in ALI caused by sepsis remains unexplored. We hypothesize that treatment with an OPN-neutralizing antibody (anti-OPN Ab) protects mice against ALI during sepsis.MethodsSepsis was induced in 8-week-old male C57BL/6 mice by cecal ligation and puncture (CLP). Anti-OPN Ab or non-immunized IgG as control, at a dose of 50 μg/mouse, was intravenously injected at the time of CLP. After 20 hours, the expression of OPN and proinflammatory cytokines in tissues and plasma was examined by real-time PCR, Western blot, and ELISA. Plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) and the lung myeloperoxidase (MPO) levels were determined by colorimetric assays. Lung damage and neutrophil infiltrations were determined by histological H&E and Gr-1 staining, respectively. The effect of recombinant mouse OPN (rmOPN) on human neutrophil-like cell (HL-60) migration was performed by Boyden chamber assays and the involvement of intracellular signaling molecules in HL-60 cells was revealed by Western blot.ResultsAfter 20 hours of sepsis, mRNA and protein levels of OPN were significantly induced in lungs, spleen, and plasma. Treatment with an anti-OPN Ab in septic mice significantly reduced the plasma levels of ALT, AST, and LDH, and the proinflammatory cytokines IL-6, IL-1β and the chemokine MIP-2, compared with the vehicle group. Similarly, the lung mRNA and protein expressions of proinflammatory cytokines and chemokine were greatly reduced in anti-OPN Ab-treated animals. The lung histological architecture, MPO and neutrophil infiltration were significantly improved in anti-OPN Ab-treated mice compared with the vehicle animals. Treatment of rmOPN in HL-60 cells significantly increased their migration, in vitro. The neutrophils treated with rmOPN remarkably increased the levels of phospho focal adhesion kinase (pFAK), phospho extracellular signal-regulated kinase (pERK) and phospho p38.ConclusionsOur findings clearly demonstrate the beneficial outcomes of anti-OPN Ab treatment in protecting against ALI, implicating a novel therapeutic strategy in sepsis.     

Overexpression of pulmonary extracellular superoxide dismutase attenuates endotoxin-induced acute lung injury

Purpose  

Superoxide is produced by activated neutrophils during the inflammatory response to stimuli such as endotoxin, can directly or indirectly injure host cells, and has been implicated in the pathogenesis of acute lung injury (ALI)/acute respiratory distress syndrome (ARDS). We wished to determine the potential for pulmonary overexpression of the extracellular isoform of superoxide dismutase (EC-SOD) to reduce the severity of endotoxin-induced lung injury.     

Metformin attenuates ventilator-induced lung injury

ABSTRACT: INTRODUCTION: Diabetic patients may develop acute lung injury less often than non-diabetics; a fact that could be partially ascribed to the usage of antidiabetic drugs, including metformin. Metformin exhibits pleiotropic properties which make it potentially beneficial against lung injury. We hypothesized that pretreatment with metformin preserves alveolar capillary permeability and, thus, prevents ventilator-induced lung injury. METHODS: Twenty-four rabbits were randomly assigned to pretreatment with metformin (250 mg/Kg body weight/day per os) or no medication for two days. Explanted lungs were perfused at constant flow rate (300 mL/min) and ventilated with injurious (peak airway pressure 23 cmH2O, tidal volume ≈17 mL/Kg) or protective (peak airway pressure 11 cmH2O, tidal volume ≈7 mL/Kg) settings for 1 hour. Alveolar capillary permeability was assessed by ultrafiltration coefficient, total protein concentration in bronchoalveolar lavage fluid (BALF) and angiotensin-converting enzyme (ACE) activity in BALF. RESULTS: High-pressure ventilation of the ex-vivo lung preparation resulted in increased microvascular permeability, edema formation and microhemorrhage compared to protective ventilation. Compared to no medication, pretreatment with metformin was associated with a 2.9-fold reduction in ultrafiltration coefficient, a 2.5-fold reduction in pulmonary edema formation, lower protein concentration in BALF, lower ACE activity in BALF, and fewer histological lesions upon challenge of the lung preparation with injurious ventilation. In contrast, no differences regarding pulmonary artery pressure and BALF total cell number were noted. Administration of metformin did not impact on outcomes of lungs subjected to protective ventilation. CONCLUSIONS: Pretreatment with metformin preserves alveolar capillary permeability and, thus, decreases the severity of ventilator-induced lung injury in this model.