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.     

Assessment of inhaled acute ammonia-induced lung injury in rats

This study examined acute toxicity and lung injury following inhalation exposure to ammonia. Male Sprague-Dawley rats (300–350?g) were exposed to 9000, 20?000, 23?000, 26?000, 30?000 or 35?000?ppm of ammonia for 20?min in a custom head-out exposure system. The exposure atmosphere, which attained steady state within 3?min for all ammonia concentrations, was monitored and verified using a Fourier transform infrared spectroscopy (FTIR) gas analyzer. Animals exposed to ammonia resulted in dose-dependent increases in observed signs of intoxication, including increased chewing and licking, ocular irritation, salivation, lacrimation, oronasal secretion and labored breathing. The LCt₅₀ of ammonia within this head-out inhalation exposure model was determined by probit analysis to be 23?672?ppm (16?489?mg/m³) for the 20?min exposure in male rats. Exposure to 20?000 or 23?000?ppm of ammonia resulted in significant body weight loss 24-h post-exposure. Lung edema increased in all ammonia-exposed animal groups and was significant following exposure to 9000?ppm. Bronchoalveolar fluid (BALF) protein concentrations significantly increased following exposure to 20?000 or 23?000?ppm of ammonia in comparison to controls. BAL cell (BALC) death and total cell counts increased in animals exposed to 20?000 or 23?000?ppm of ammonia in comparison to controls. Differential cell counts of white blood cells, neutrophils and platelets from blood and BALF were significantly increased following exposure to 23?000?ppm of ammonia. The following studies describe the validation of a head-out inhalation exposure model for the determination of acute ammonia-induced toxicity; this model will be used for the development and evaluation of potential therapies that provide protection against respiratory and systemic toxicological effects.     

Attempts to counteract phosgene-induced acute lung injury by instant high-dose aerosol exposure to hexamethylenetetramine,cysteine or glutathione

Phosgene is an important high-production-volume intermediate with widespread industrial use. Consistent with other lung irritants causing ALI (acute lung injury), mode-of-action-based countermeasures remain rudimentary. This study was conducted to analyze whether extremely short high-level exposure to phosgene gas could be mitigated using three different inhaled nucleophiles administered by inhalation instantly after exposure to phosgene. Groups of young adult male Wistar rats were acutely exposed to carbonyl chloride (phosgene) using a directed-flow nose-only mode of exposure of 600?mg/m³ for 1.5?min (225?ppm?×?min). Immediately after exposure to phosgene gas the rats were similarly exposed to three strong nucleophiles with and without antioxidant properties for 5 or 15?min. The following nucleophiles were used: hexamethylenetetramine (HMT), l-cysteine (Cys), and l-glutathione (GSH). The concentration of the aerosol (mass median aerodynamic diameter 1.7–2?µm) was targeted to be in the range of 1?mg/L. Cys and GSH have antioxidant properties in addition. The calculated alveolar molar dosage of phosgene was 9 µmol/kg. At 15-min exposure duration, the respective inhaled dose of HMT, Csy, and GSH were 111, 103, and 46 µmol/kg, respectively. The alveolar dose of drugs was ~10-times lower. The efficacy of treatment was judged by protein concentrations in bronchoalveolar lavage fluid (BALF) collected 1 day post-exposure. In spite of using optimized aerosolization techniques, none of the nucleophiles chosen had any mitigating effect on BALF-protein extravasation. This finding appear to suggest that inhaled phosgene gas acylates instantly nucleophilic moieties at the site of initial deposition and that the resultant reaction products can not be reactivated even following instant inhalation treatment with competing nucleophilic agents. In spite of using maximal technically attainable concentrations, it appears to be experimentally challenging to deliver such nucleophiles to the lower respiratory tract at high dosages.     

非诺贝特改善脂多糖诱导的急性肺损伤及其机制研究

摘要：目的　探究非诺贝特（Fen）对急性肺损伤（ALI）的作用及机制。方法　（1）体内实验。30只C57BL/6雄性小鼠采用随机数字表法分成6组：正常组,模型组（LPS组）,阳性药地塞米松（DXMS）组,Fen低、中、高剂量（20、40、80 mg/kg）组。分组给药12 h后,收集肺泡灌洗液（BALF）,处死小鼠,获取肺组织,记录肺组织湿/干质量比;酶联免疫吸附试验（ELISA）检测肺组织肿瘤坏死因子（TNF）-α、白细胞介素（IL）-6和IL-1β含量;BCA比色法和瑞氏-吉姆萨染色检测BALF中总蛋白含量和免疫细胞数目;苏木精-伊红（HE）染色观察肺组织病变并进行病理评分。Western blot检测肺组织B淋巴细胞瘤-2蛋白（Bcl-2）、Bcl-2相关X蛋白（Bax）及c-Jun氨基末端激酶（JNK）、磷酸化JNK（p-JNK）表达。（2）体外实验。实验设Control、LPS（10 mg/L）、LPS+Fen（5 μmol/L）、LPS+Fen（10 μmol/L）、LPS+Fen（20 μmol/L）组。A549细胞经LPS（10 mg/L）处理后分别加入5、10、20 μmol/L的Fen处理12 h,分别用DCFH-DA、Annexin V-FITC/PI法和Western blot检测Fen对A549细胞ROS、凋亡和凋亡相关蛋白Bcl-2、Bax及p-JNK影响。另选取LPS（10 mg/L）+Fen（20 μmol/L）处理后添加H2O2（100 μmol/L）,观察细胞ROS、凋亡率和凋亡相关蛋白Bcl-2、Bax表达变化。此外,选取LPS（10 mg/L）+Fen（20 μmol/L）处理后添加JNK激动剂Anisomycin（3 μmol/L）,观察Bcl-2、Bax表达变化。结果　（1）与正常组相比,模型组小鼠肺组织湿/干质量比,肺组织损伤评分,TNF-α、IL-6、IL-1β含量,肺泡灌洗液总蛋白含量,免疫细胞数目,p-JNK和Bax表达均出现显著升高,Bcl-2表达显著降低。与模型组相比,Fen低、中、高剂量组上述指标变化均被逆转。（2）Fen能显著减少LPS诱导的A549细胞ROS含量,降低凋亡率,抑制p-JNK和Bax表达并促进Bcl-2表达。H2O2可逆转Fen引起的上述效应。Anisomycin也能抑制Fen引起的Bcl-2上调和Bax蛋白下调。结论　Fen可通过ROS/JNK信号抑制细胞凋亡,从而减轻ALI。     

二甲基阿米洛利对大鼠油酸性急性肺损伤的保护作用

The effect of Na⁺/H⁺ exchange inhibitor dimethyl amiloride(DMA) on rat acute lung injury induced by oleic acid was studied. Five hours after administration (iv) of oleic acid (10 mL·kg^-1), pulmonary coefficient, lung wet/dry weight ratio and protein content, lactic acid dehydrogenase(LDH) activity, total white blood cell(WBC) and polymorphonuclear leukocyte(PMN) in bronchoalveolar lavage(BAL) of rat were increased significantly. However, after pretreatment with DMA(0.2 mg·kg^-1 iv) for 10 min, the pulmonary coefficient and lung wet/dry weight ratio were decreased from 1.12±0.06 to 0.87±0.05 and 5.8±0.5 to 4.5±0.3, respectively. The protein content, LDH activity, total WBC and PMN in BAL were also reduced from (1.69±0.15) g·L^-1 to (1.05±0.13) g·L^-1, (3.37±0.25) μmol·min^-1·L^-1 to (0.81±0.08) μmol·min^-1·L^-1, (4.3±0.9) ×10⁶·L^-1 to (2.4±0.8) ×10⁶·L^-1 and (2.4±0.4) ×10⁶·L^-1 to (1.6±0.4) ×10⁶·L^-1, respectively. These results suggest that activation of Na⁺/H⁺ exchange be involved in the acute rat lung injury induced by oleic acid and that inhibitor of sodium-hydrogen exchange prevent the rat lungs from this injury.     

二甲基阿米洛利对大鼠油酸性急性肺损伤的保护作用

呼吸窘迫综合征（ｒｅｓｐｉｒａｔｏｒｙｄｉｓｔｒｅｓｓｓｙｎｄｒｏｍｅ,ＲＤＳ）是一种死亡率高达５０％以上的以肺泡毛细血管损伤为特征的疾病［１］．油酸（ｏｌｅｉｃａｃｉｄ,ＯＡ）性肺损伤动物模型产生与ＲＤＳ病人相似的表现,已被广泛用于ＲＤＳ发病机理和...     

Protective effect of raloxifene on lipopolysaccharide and acid- induced acute lung injury in rats

Aim： To evaluate the protective effect of oral raloxifene on acute lung injury. Methods： Thirty adult, male Sprague-Dawley rats each weighing 180-210 g were used and divided into 3 groups： the raloxifene-lipopolysaccharide （LPS）-HCI group （n=10）, the LPS-raloxifene-HCl group （n=10）, and the placebo group （n=10）. All the rats were injected intraperitoneally （ip） with 5 mg/kg LPS, and raloxifene （30 mg/kg） was orally administered 1 h before and 14 h after LPS injection into the raloxifene-LPS-HCl and the LPS-raloxifene-HCl groups, respectively; the placebo group received nothing. Sixteen hours after LPS injection, all the animals were anesthetized and the femoral artery was cannulated. All the rats received a direct intratracheal （IT） injection ofHCl （pH 1.2; 0.5 mL/kg）. The mean arterial pressure （MAP） and blood gas concentrations were measured. Fifteen rats （5 in each group, respectively） underwent a micro positron emission tomography （microPET） scan of the thorax 4 h after HCI instillation. The wet/dry （W/D） weight ratio determination and histopathological examination were also performed. Results： The rats in the LPS-raloxifene-HCl group had a lower [^18F]fluorodeoxyglucose uptake compared with the rats in the placebo group （4.67±1.33 vs 9.01±1.58, respectively, P〈0.01）. The rats in the LPS-raloxifene-HCl group also had a lower histological lung injury score （8.20± 1.23 vs 12.6±0.97, respectively, P〈0.01） and W/D weight ratio （5.335±0.198 vs 5.886±0.257, respectively, P〈0.01） compared to the placebo group. The rats in this group also showed better pulmonary gas exchange and more stable mean arterial pressure （MAP） compared to the placebo group. Conclusion： Raloxifene provides a significant protective effect on acute lung injury in rats induced first by LPS ip injection and then by HCI IT instillation.     

Measurement of various respiratory dynamics parameters following acute inhalational exposure to soman vapor in conscious rats

Abstract

Respiratory dynamics were investigated in head-out plethysmography chambers following inhalational exposure to soman in untreated, non-anesthetized rats. A multipass saturator cell was used to generate 520, 560 and 600?mg?×?min/m³ of soman vapor in a customized inhalational exposure system. Various respiratory dynamic parameters were collected from male Sprague-Dawley rats (300--350?g) during (20?min) and 24?h (10?min) after inhalational exposure. Signs of CWNA-induced cholinergic crisis were observed in all soman-exposed animals. Percentage body weight loss and lung edema were observed in all soman-exposed animals, with significant increases in both at 24?h following exposure to 600?mg?×?min/m³. Exposure to soman resulted in increases in respiratory frequency (RF) in animals exposed to 560 and 600?mg?×?min/m³ with significant increases following exposure to 560?mg?×?min/m³ at 24?h. No significant alterations in inspiratory time (IT) or expiratory time (ET) were observed in soman-exposed animals 24?h post-exposure. Prominent increases in tidal volume (TV) and minute volume (MV) were observed at 24?h post-exposure in animals exposed to 600?mg?×?min/m³. Peak inspiratory (PIF) and expiratory flow (PEF) followed similar patterns and increased 24?h post-exposure to 600?mg?×?min/m³ of soman. Results demonstrate that inhalational exposure to 600?mg?×?min/m³ soman produces notable alterations in various respiratory dynamic parameters at 24?h. The following multitude of physiological changes in respiratory dynamics highlights the need to develop countermeasures that protect against respiratory toxicity and lung injury.     

Pulmonary delivery of siRNA against acute lung injury/acute respiratory distress syndrome

The use of small interfering RNAs (siRNAs) has been under investigation for the treatment of several unmet medical needs, including acute lung injury/acute respiratory distress syndrome (ALI/ARDS) wherein siRNA may be implemented to modify the expression of pro-inflammatory cytokines and chemokines at the mRNA level. The properties such as clear anatomy, accessibility, and relatively low enzyme activity make the lung a good target for local siRNA therapy. However, the translation of siRNA is restricted by the inefficient delivery of siRNA therapeutics to the target cells due to the properties of naked siRNA. Thus, this review will focus on the various delivery systems that can be used and the different barriers that need to be surmounted for the development of stable inhalable siRNA formulations for human use before siRNA therapeutics for ALI/ARDS become available in the clinic.