Adenovirus-delivered angiopoietin-1 treatment for phosgene-induced acute lung injury

Abstract

Context: Exposure to phosgene can result in an acute lung injury, leading to pulmonary edema and even death. Angiopoietin-1 (Ang1) is a critical factor for vascular stabilization due to its ability to reduce endothelial permeability and inflammation.

Objective: In this study, the histopathological changes of the lungs after exposure to phosgene and the effect of Ang1 treatment were examined.

Materials and methods: Rats were exposed to phosgene gas at 8.33?g/m³ for 5?min. Ang1 overexpressing rats were established by an intravenous injection of adenovirus-Ang1 (Ad/Ang1). The histological changes of the lung were examined by Haematoxylin-Eosin (H&E) staining and fluorescence microscopy. The inferior lobe was used for the determination of the ratio of wet weight to dry weight of the lung. The concentration of cytokines in the serum and bronchoalveolar lavage fluid was determined by enzyme-linked immunosorbent assay.

Results: The pathological analysis showed signs of inflammation and edema, evident from a significant increase in the number of leukocytes in bronchoalveolar lavage fluid and the ratio of wet to dry weight of the lungs. The lung injury induced by phosgene was markedly reduced after the injection of Ad/Ang1. The increase of IL-1β and IL-17 and decrease of vascular endothelial growth factor in the serum and bronchoalveolar lavage fluid of phosgene-exposed animals were abolished by the administration of Ad/Ang1.

Discussion and conclusions: Ang1 has the beneficial effects on phosgene-induced lung injury. The adenovirus-delivered Ang1 may have the potential as a novel approach for the treatment of the acute lung injury caused by phosgene gas inhalation in humans.     

Bone marrow-derived mesenchymal stem cells attenuate phosgene-induced acute lung injury in rats

Abstract

Accidental phosgene exposure could result in acute lung injury (ALI), effective therapy is needed for the patients with phosgene-induced ALI. As a type of cells with therapeutic potential, mesenchymal stem cells (MSCs) have been showed its efficacy in multiple diseases. Here, we assessed the therapeutic potential of MSCs in phosgene-induced ALI and explored the related mechanisms. After isolation and characterization of rat bone marrow MSCs (BMMSCs), we transplanted BMMSCs into the rats exposed to phosgene and observed significant improvement on the lung wet-to-dry ratio and partial oxygen pressure (PaO₂) at 6, 24, 48?h after phosgene exposure. Histological analyses revealed reduced sign of pathological changes in the lungs. Reduced level of pro-inflammatory tumor necrosis factor α and increased level of anti-inflammatory factor interleukin-10 were found in both bronchoalveolar lavage and plasma. Significant increased expression of epithelial cell marker AQP5 and SP-C was also found in the lung tissue. In conclusion, treatment with MSC markedly decreases the severity of phosgene-induced ALI in rats, and these protection effects were closely related to the pulmonary air blood barrier repairment and inflammatory reaction regulation.     

Silymarin attenuates paraquat‐induced lung injury via Nrf2‐mediated pathway in vivo and in vitro

The present study aims to investigate the impacts and mechanisms of silymarin on paraquat (PQ)‐induced lung injury in vivo and in vitro. In in vivo experiments, a total of 32 male Sprague‐Dawley (SD) rats were randomly divided into four groups. The rats were killed on day 3. Histopathological changes in lung tissue were examined using HE and Masson's trichrome staining. Biomarkers of neutrophil activation, pulmonary oedema, pulmonary fibrosis, lung permeability and oxidative stress were detected. Several proinflammatory mediators and antioxidant related proteins were measured. In in vitro experiments, A549 cells were transfected with Nrf2 special siRNA to investigate the roles of Nrf2. The results show that silymarin administration abated PQ‐induced lung histopathologic changes, decreased inflammatory cell infiltration and lung wet weight/dry weight (W/D) ratio, suppressed myeloperoxidase (MPO) activity and nitric oxide (NO)/inducible nitric oxide synthases (iNOS) expression, downregulated hydroxyproline (HYP) levels, reduced total protein concentration and proinflammatory mediator release, and improved oxidative stress (malondialdehyde, MDA; superoxide dismutase, SOD; catalase, CAT; and glutathione peroxidase, GSH‐Px) in lung tissue and serum. Meanwhile, treatment with silymarin upregulated the levels of nuclear factor‐erythroid‐2‐related factor 2 (Nrf2), heme oxygenase‐1 (HO‐1) and NAD(P)H:quinone oxidoreductase‐1(NQO1). However, the addition of Nrf2 siRNA reduced the expression of Nrf2‐mediated antioxidant protein HO‐1 and thus reversed the protective effects of silymarin against oxidative stress and inflammatory response. These results suggest that silymarin may exert protective effects against PQ‐induced lung injury. Its mechanisms were associated with the Nrf2‐mediated pathway. Therefore, silymarin may be a potential therapeutic drug for lung injury.     

Corticosteroids found ineffective for phosgene-induced acute lung injury in rats

Various therapeutic regimes have been proposed with limited success for treatment of phosgene-induced acute lung injury (P-ALI). Corticoids were shown to be efficacious against chlorine-induced lung injury but there is still controversy whether this applies also to P-ALI. This study investigates whether different regimen of curatively administered budesonide (BUD, 10 mg/kg bw, i.p. bid; 100 mg/m³ × 30 min, nose-only inhalation), mometasone (MOM, 3 mg/kg bw, i.p. bid) and dexamethasone (DEX, 10, 30 mg/kg bw, i.p. bid), show efficacy to alleviate P-ALI. Efficacy of drugs was judged by nitric oxide (eNO) and carbon dioxide (eCO₂) in exhaled air and whether these non-invasive biomarkers are suitable to assess the degree of airway injury (chlorine) relative to alveolar injury (phosgene). P-ALI related analyses included lung function (enhanced pause, Penh), morbidity, increased lung weights, and protein in bronchial alveolar lavage fluid (BALF) one day postexposure. One of the pathophysiological hallmarks of P-ALI was indicated by increased Penh lasting for approximately 20 h postexposure. Following the administration of BUD, this increase could be suppressed; however, without significant improvement in survival and lung edema (increased lung weights and BALF-protein). Collectively, protocols shown to be efficacious for chlorine (Chen et al., 2013) were ineffective and even increased adversity in the P-ALI model. This outcome warrants further study to seek for early biomarkers suitable to differentiate chlorine- and phosgene-induced acute lung injury at yet asymptomatic stage. The patterns of eNO and eCO₂ observed following exposure to chlorine and phosgene may be suitable to guide the specialized clinical interventions required for each type of ALI.     

N-acetylcysteine abrogates acute lung injury induced by endotoxin

1. Acute lung injury (ALI) or acute respiratory distress syndrome is a serious clinical problem with high mortality. N-Acetylcysteine (NAC) is an anti-oxidant and a free radical scavenger. It has been reported recently that NAC ameliorates organ damage induced by endotoxin (lipopolysaccharide; LPS) in conscious rats. The present study was designed to evaluate the effects of NAC on LPS-induced ALI and other changes in anaesthetized rats. 2. Sprague-Dawley rats were anaesthetized with pentobarbital (40 mg/kg, i.p.). Endotracheal intubation was performed to provide artificial ventilation. Arterial pressure and heart rate were monitored. The extent of ALI was evaluated with the lung weight (LW)/bodyweight ratio, LW gain, exhaled nitric oxide (NO) and protein concentration in bronchoalveolar lavage (PCBAL). Haematocrit, white blood cells, plasma nitrate/nitrite, methyl guanidine (MG), tumour necrosis factor (TNF)-alpha and interleukin (IL)-1b were measured. Pathological changes in the lung were examined and evaluated. 3. Endotoxaemia was produced by injection of 10 mg/kg, i.v., LPS (Escherichia coli). Animals were randomly divided into three groups. In the vehicle group, rats received an i.v. drip of physiological saline solution (PSS) at a rate of 0.3 mL/h. The LPS group received an i.v. drip of PSS for 1 h, followed by LPS (10 mg/kg by slow blous injection, i.v., over 1-2 min). Rats in the LPS + NAC group received NAC by i.v. drip at a rate of 150 mg/kg per h (0.3 mL/h) for 60 min starting 10 min before LPS administration (10 mg/kg by slow blous injection, i.v., over 1-2 min). Each group was observed for a period of 6 h. 4. N-Acetylcysteine treatment improved the LPS-induced hypotension and leukocytopenia. It also reduced the extent of ALI, as evidenced by reductions in LW changes, exhaled NO, PCBAL and lung pathology. In addition, NAC diminished the LPS-induced increases in nitrate/nitrite, MG, TNF-a and IL-1b. 5. In another series of experiments, LPS increased the mortality rate compared with the vehicle group (i.v. drip of PSS at a rate of 0.3 mL/h) during a 6 h observation period. N-Acetylcysteine, given 10 min prior to LPS, significantly increased the survival rate. 6. The results of the present study suggest that NAC exerts a protective effect on the LPS-induced ALI. The mechanisms of action may be mediated through the reduction of the production of NO, free radicals and pro-inflammatory cytokines.     

S-allylmercaptocysteine ameliorates lipopolysaccharide-induced acute lung injury in mice by inhibiting inflammation and oxidative stress via nuclear factor kappa B and Keap1/Nrf2 pathways

The garlic-derived organosulfur compound S-allylmercaptocysteine (SAMC) has been reported to exhibit anti-inflammatory and anti-oxidative activities, whereas its potential therapeutic effect on lipopolysaccharide (LPS)-induced acute lung injury (ALI) is unknown. In this study, we focused on exploring the therapeutic effects of SAMC on LPS-induced ALI mice and the involvement of underlying molecular mechanisms. BalB/c mice were treated with SAMC (10, 30 and 60 mg/kg) or positive control N-acetylcysteine (NAC, 500 mg/kg) by gavage after intratracheal instillation of LPS for 30 min and were sacrificed 24 h after LPS administration. Our results indicate that the treatment with SAMC not only ameliorated the histological changes but also decreased LPS-triggered lung edema. Moreover, SAMC displayed an anti-inflammatory effect through reducing inflammatory cells infiltration, myeloperoxidase (MPO) formation and inhibiting pro-inflammatory cytokines/mediator production including tumor necrosis factor alpha (TNF-α), interleukin-1β (IL-1β), interleukin-6 (IL-6), inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX2) via suppressing the activation of nuclear factor-kappaB (NF-κB) signaling pathway. Furthermore, SAMC attenuated oxidative stress evoked by LPS via diminishing malondialdehyde (MDA) formation and reversing glutathione (GSH) and superoxide dismutase (SOD) depletion. Meanwhile, SAMC up-regulated expressions of endogenous antioxidant/detoxifying proteins including heme oxygenase-1 (HO-1) and NAD(P)H: quinone oxidoreductase 1(NQO1) through reversing the suppression of Kelch-like ECH-associated protein 1 (Keap1)/nuclear factor erythroid-2 related factor 2 (Nrf2) signaling pathway. Our results demonstrate that SAMC effectively attenuated LPS-induced ALI which was largely dependent upon inhibition of inflammation and oxidative stress via NF-κB and Keap1/Nrf2 signaling pathways.     

Isoforskolin pretreatment attenuates lipopolysaccharide-induced acute lung injury in animal models

Isoforskolin was isolated from Coleus forskohlii native to Yunnan in China. We hypothesize that isoforskolin pretreatment attenuates acute lung injury induced by lipopolysaccharide (endotoxin). Three acute lung injury models were used: situ perfused rat lung, rat and mouse models of endotoxic shock. Additionally, lipopolysaccharide stimulated proinflammatory cytokine production was evaluated in human mononuclear leukocyte. In situ perfused rat lungs, pre-perfusion with isoforskolin (100, and 200 μM) and dexamethasone (65 μM, positive control) inhibited lipopolysaccharide (10 mg/L) induced increases in lung neutrophil adhesion rate, myeloperoxidase activity, lung weight Wet/Dry ratio, permeability-surface area product value, and tumor necrosis factor (TNF)-α levels. In rats, pretreatments with isoforskolin (5, 10, and 20 mg/kg, i.p.) and dexamethasone (5mg/kg, i.p.) markedly reduced lipopolysaccharide (6 mg/kg i.v.) induced increases of karyocyte, neutrophil counts and protein content in bronchoalveolar lavage fluid, and plasma myeloperoxidase activity. Lung histopathology showed that morphologic changes induced by lipopolysaccharide were less pronounced in the isoforskolin and dexamethasone pretreated rats. In mice, 5 mg/kg isoforskolin and dexamethasone caused 100% and 80% survival, respectively, after administration of lipopolysaccharide (62.5mg/kg, i.v., 40% survival if untreated). In human mononuclear leukocyte, isoforskolin (50, 100, and 200 μM) and dexamethasone (10 μM) pre-incubation lowered lipopolysaccharide (2 μg/mL) induced secretion of the cytokine TNF-α, and interleukins (IL)-1β, IL-6, and IL-8. In conclusion, pretreatment with isoforskolin attenuates lipopolysaccharide-induced acute lung injury in several models, and it is involved in down-regulation of inflammatory responses and proinflammatory cytokines TNF-α, IL-1β, IL-6, and IL-8.     

P选择素在油酸诱导急性肺损伤大鼠肺组织中的表达及N-乙酰半胱氨酸对其影响的研究

目的探讨油酸(Olic Acid,OA)诱导的急性肺损伤(Acute Lung Injury,ALI)大鼠肺血管内皮P-选择素(P-selectin,Ps)表达的变化及N-乙酰半胱氨酸(N-acetylcysteine,NAC)的保护作用。方法成年雄性SD大鼠42只按随机化原则分为3组:油酸组(OA组n=18);对照组(n=6); N-乙酰半胱氨酸 油酸组(NAC组,n=18);按注射油酸后不同时间随机分为3组,1小时、3小时、6 小时组,行P选择素免疫组织化学染色及光密度测值,并检测肺组织匀浆髓过氧化物酶(MPO)、超氧化物岐化酶(SOD)、丙二醛(MDA)。结果Ps在OA诱导的ALI大鼠肺血管内皮1小时出现表达,3 小时表达达高峰,持续表达6小时(P<0．01);OA组各时点MPO、MDA升高,与对照组比较差异均有显著性(P<0．01),NAC组各时点MPO、MDA均低于相应时点OA组(P<0．01),但均高于对照组(P<0．01);OA组SOD明显降低,与对照组比较差异明显(P<0．01),NAC组各时点SOD均高于相应时点OA组(P<0．01),但均低于对照组(P<0．01);Ps表达与MPO、MDA成正相关(r=0．793, 0．886;P<0．01)。结论Ps在OA诱导的ALI大鼠肺血管内皮表达1小时升高,3小时表达达高峰, 持续表达6小时;NAC通过清除氧自由基抑制Ps在肺血管内皮的表达,对OA诱导ALI大鼠起保护作用。     

Adenovirus-delivered angiopoietin-1 ameliorates phosgene-induced acute lung injury via inhibition of NLRP3 inflammasome activation

Objective: Angiopoietin-1 (Ang1) is reported to have the ability to attenuate endothelial permeability and inflammation during the stress condition and is considered to play a critical role in vascular stabilization. The aim of this study was to investigate the mechanisms involved in the protective effects of adenovirus-delivered Ang1 in phosgene-induced acute lung injury (ALI).

Methods: ALI was induced in rats by phosgene exposure at 8.33?g/m³ for 5?min, followed by an intravenous injection of adenovirus-Ang1 (Ad/Ang1). The histologic changes of the lung were evaluated with H&;E staining. The levels of cytokines in the serum and bronchoalveolar lavage fluid (BALF) were determined by ELISA. NLRP3 inflammasome activation was assessed with immunohistochemistry, RT-PCR, Western blotting and TUNEL staining.

Results: Histologic analyses suggested that reduced severity in phosgene-induced ALI with Ad/Ang1 treatment. Reduced levels of IL-1β, IL-18 and IL-33 were found in both serum and BALF samples from Ad/Ang1-treated ALI rats induced by phosgene. Moreover, immunohistochemistry analysis revealed that Ad/Ang1 treatment inhibited the NLRP3 inflammasome activation. Decreased mRNA and protein levels of NLRP3 and caspase-1 were found in phosgene-exposed rats treated with Ad/Ang1. In addition, TUNEL staining indicated a decrease in pyroptosis in phosgene-exposed rats treated with Ad/Ang1.

Conclusions: Ang1 exerts beneficial effects on phosgene-induced lung injury via inhibition of NLRP3 inflammasome activation. Disruption of NLRP3 inflammasome activation might be served as therapeutic modality for the treatment of phosgene-induced ALI.     

N-乙酰半胱氨酸对急性胰腺炎大鼠肺组织中趋化因子MCP-1、MIP-2表达的影响

目的 探讨单核细胞趋化蛋白1(MCP-1)与巨噬细胞炎性蛋白2(MIP-2)在急性胰腺炎(AP)相关性肺损伤中的作用,观察N-乙酰半胱氨酸(NAC)对其表达的影响.方法 35只SD大鼠随机分为假手术(SO)组、急性坏死性胰腺炎(ANP)3、6、12 h组和NAC干预3、6、12 h组.采用4%牛磺胆酸钠胰胆管逆行注射制备ANP动物模型,NAC组在诱导ANP前30 min给予腹腔注射NAC 500 mg/kg.检测血淀粉酶、肺泡灌洗液/血清伊文氏兰比值、髓过氧化酶(MPO),观察肺病理组织学改变,采用逆转录-PCR检测肺组织中MCP-1与MIP-2 mRNA的表达.结果 ANP各组血淀粉酶明显升高,肺MPO、泡灌洗液/血清伊文氏兰比值随肺损伤的加重而升高.SO组肺组织MCP-1 mRNA、MIP-2 mRNA表达阴性或弱阳性;ANP各组肺组织中均有MCP-1 mRNA与MIP-2mRNA表达上调,并随ANP病变的加重表达逐渐增强.MCP-1与MIP-2 mRNA的表达与胰腺的病理损伤成正相关.经NAC干预后,趋化因子MCP-1 mRNA与MIP-2 mRNA的表达下调,白细胞浸润减少,肺血管通透性下降,肺组织损伤得到改善(P＜0.05或P＜0.01).结论 趋化因子MCP-1、MIP-2参与AP相关性肺损伤.NAC通过下调趋化因子MCP-1与MIP-2的表达使AP相关性肺损伤得到改善.     

Mesenchymal stem cell-derived exosomes attenuate phosgene-induced acute lung injury in rats

Objective: We have previously found that mesenchymal stem cell (MSC) therapy can ameliorate phosgene-induced acute lung injury (ALI). Moreover, exosomes can be used as a cell-free alternative therapy. In the present study, we aimed to assess the effect of MSC-derived exosomes on phosgene-induced ALI.

Methods: MSC-derived exosomes were isolated from MSCs through ultracentrifugation. Sprague-Dawley (SD) rats were exposed to phosgene at 8.33?g/m³ for 5?min. MSC-derived exosomes were intratracheally administered and rats were sacrificed at the time points of 6, 24 and 48?h.

Results: Compared with the phosgene group, MSC-derived exosomes reversed respiratory function alterations, showing increased levels of TV, PIF, PEF and EF50 as well as decreased levels of RI and EEP. Furthermore, MSC-derived exosomes improved pathological alterations and reduced wet-to-dry ratio and total protein content in BALF. MSC-derived exosomes reduced the levels of TNF-α, IL-1β and IL-6 and increased the IL-10 level in BALF and plasma. MSC-derived exosomes suppressed the MMP-9 level and increased the SP-C level.

Conclusions: MSC-derived exosomes exerted beneficial effects on phosgene-induced ALI via modulating inflammation, inhibiting MMP-9 synthesis and elevating SP-C level.     

Therapeutic inhibition of CXCR2 by Reparixin attenuates acute lung injury in mice

Background and purpose:

Acute lung injury (ALI) remains a major challenge in critical care medicine. Both neutrophils and chemokines have been proposed as key components in the development of ALI. The main chemokine receptor on neutrophils is CXCR2, which regulates neutrophil recruitment and vascular permeability, but no small molecule CXCR2 inhibitor has been demonstrated to be effective in ALI or animal models of ALI. To investigate the functional relevance of the CXCR2 inhibitor Reparixin in vivo, we determined its effects in two models of ALI, induced by either lipopolysaccharide (LPS) inhalation or acid instillation.

Experimental approach:

In two ALI models in mice, we measured vascular permeability by Evans blue and evaluated neutrophil recruitment into the lung vasculature, interstitium and airspace by flow cytometry.

Key results:

Pharmacological inhibition of CXCR2 by Reparixin reduced CXCL1-induced leukocyte arrest in the microcirculation of the cremaster muscle, but did not influence arrest in response to leukotriene B₄ (LTB₄) demonstrating specificity. Reparixin (15 μg g⁻¹) reduced neutrophil recruitment in the lung by approximately 50% in a model of LPS-induced ALI. A higher dose did not provide additional reduction of neutrophil recruitment. This dose also reduced accumulation of neutrophils in the interstitial compartment and vascular permeability in LPS-induced ALI. Furthermore, both prophylactic and therapeutic application of Reparixin improved gas exchange, and reduced neutrophil recruitment and vascular permeability in a clinically relevant model of acid-induced ALI.

Conclusions and implications:

Reparixin, a non-competitive allosteric CXCR2 inhibitor attenuates ALI by reducing neutrophil recruitment and vascular permeability.     

Emodin attenuates acute lung injury in Cecal-ligation and puncture rats

Acute lung injury (ALI) is a major cause of sepsis-induced acute respiratory failure. Emodin has been considered to play a protective role for acute lung edema in cecal ligation and puncture (CLP)-induced sepsis model. In this study we aimed to investigate whether emodin could improve CLP-induced lung sepsis via regulating aquaporin (AQP) and tight junction (TJ), inflammatory factors, and pulmonary apoptosis. The results showed that sepsis-induced pulmonary pathological changes were significantly improved after emodin treatment. Emodin was found to upregulate AQP and TJ expression in the CLP model. Meanwhile, inflammatory cytokine release and pulmonary apoptosis was remarkably reduced after emodin treatment in lung sepsis. Our data demonstrated that emodin could suppresse inflammation, restore pulmonary epithelial barrier and reduce mortality in CLP-induced ALI, suggesting the potential therapeutic application of emodin in sepsis.     

急性肾损伤诱导急性肺损伤的研究进展

急性肾损伤是一种ICU患者中常见的疾病,致死率较高,当合并肺损伤时,致死率显著提高,可达到80%。急性肾损伤可导致全身体液灌注量增加,血浆渗透压升高进而引起肺水肿和急性呼吸衰竭。同时,炎症反应,氧化应激,细胞凋亡和可溶性调节因子代谢异常等也可能参与急性肾损伤诱导的肺损伤。对急性肾损伤诱导肺损伤的临床认识和可能发病机制的研究,将有助于临床疾病的治疗和死亡率的降低,同时也将有助于对其它肾脏疾病发病机制的认识。     

血管生成素2在大鼠内毒性急性肺损伤中的作用与机制研究

目的 探讨血管生成素-2(Ang-2)在脂多糖(LPS)致大鼠急性肺损伤(ALI)时的表达及其机制。方法 48只清洁级SD大鼠随机分为正常对照组、1 mg/kg LPS组、5 mg/kg LPS组和10 mg/kg LPS组,每组12只。LPS组尾静脉注射不同剂量LPS复制ALI模型,对照组注射同等体积生理盐水,留取肺组织标本,观察肺湿/干重(W/D)比值、HE染色光镜观察肺组织标本病理改变并进行肺损伤评分,各组ELISA法检测血浆中Ang-2与血管内皮生长因子(VEGF)的表达,Westernblot方法检测肺组织中Ang-2的蛋白表达情况。结果 LPS注射进入大鼠尾静脉6 h后,光镜下可见肺组织内的炎性细胞浸润,肺泡隔增宽,肺间质水肿和肺结构破坏等病理改变;LPS各组的肺损伤评分与W/D比值明显高于对照组(P<0.05);LPS不同剂量组血浆中Ang-2与VEGF的表达水平较对照组明显增高(P<0.05),血浆中Ang-2的表达与VEGF、肺损伤评分呈正相关(r=0.826,P<0.05;r=0.775,P<0.05);LPS不同剂量组与Ang-2蛋白的表达水平呈现剂量效应关系(P<0.05)。结论 Ang-2参与大鼠ALI的发病过程,且Ang-2水平增高与ALI严重程度有关。     

N-乙酰半胱氨酸在急性肺损伤中的保护作用

目的观察N-乙酰半胱氨酸(NAC)在急性肺损伤(ALI)中的保护作用。方法建立脂多糖(LPS)诱导的大鼠急性肺损伤模型,将24只大鼠随机分为空白对照组、LPS组和NAC组,测定各组肺含水量、湿/干质量比值,对支气管肺泡灌洗液(BALF)中白细胞计数,并用ELISA法测定肿瘤坏死因子(TNF-α)的量。结果NAC组大鼠肺含水量、湿/干质量比值、TNF-α含量、白细胞计数均少于LPS组(P<0.05)。结论N-乙酰半胱氨酸能通过阻断细胞因子和炎性介质的释放来抑制大鼠急性肺损伤的肺部炎症反应。     

Glutamine attenuates hyperoxia-induced acute lung injury in mice

1. Glutamine is an amino acid that is used to treat various diseases. Glutamine has been reported to have protective effects in human pulmonary epithelia-like cells exposed to hyperoxia. However, the effects of glutamine in hyperoxia-induced lung injury have not been investigated in vivo .
2. Mice treated with saline or glutamine [(750 mg/kg) intravenously] were randomly exposed to hyperoxia for 48 or 72 h. Control mice treated with saline or glutamine were exposed to room air. Cytokine levels in bronchoalveolar lavage fluid (BALF), heat shock protein (HSP) 70, the wet/dry (W/D) weight ratio, malondialdehyde (MDA) levels, myeloperoxidase (MPO) activity and pathoglogical findings in lung tissue were evaluated to determine the effects of glutamine on acute lung injury. In addition, survival was monitored.
3. Lung expression of HSP70 was significantly enhanced in both the control (room air) and 48 and 72 h hyperoxic glutamine-treated mice. The W/D ratio, BALF concentrations of tumour necrosis factor-α and interleukin-6, MDA levels, MPO activity, neutrophil infiltration and interstitial oedema in lung tissue were significantly lower at 48 and 72 h of hyperoxia in glutamine-treated mice compared with saline-treated mice.
4. In a separate series of experiments evaluating survival, after 96 h continuous exposure to hyperoxia, all saline-treated mice died. In contrast, all glutamine-treated mice died after 108 h exposure to hyperoxia.
5. The data suggest that glutamine administered to mice during hyperoxia has a protective effect against hyperoxia-induced acute lung injury and improves survival.