黄磷及其化合物急性吸入致大鼠急性肺损伤或急性呼吸窘迫综合征模型的制作

目的建立黄磷及其化合物急性吸入致大鼠急性肺损伤（ALI）/急性呼吸窘迫综合征（ARDS）的模型。方法健康SD大鼠48只随机分为对照组以及实验组（0、4、12、24、48 h时间点处死）。采用自制染毒装置,间歇染毒形成ALI/ARDS模型。观察ALI/ARDS大鼠动脉血气分析以及肺系数和肺组织病理变化。结果肺损伤后大鼠动脉血气分析以及肺组织病理改变明显恶化,肺系数较对照组明显增大。结论成功地建立了黄磷及其化合物急性吸入致大鼠ALI/ARDS的模型,为黄磷及其化合物吸入中毒的防治研究提供良好实验基础,同时也适用于其他气体吸入致ARDS的实验研究。     

Tight junction disruption by cadmium in an in vitro human airway tissue model

Background

The cadmium (Cd) present in air pollutants and cigarette smoke has the potential of causing multiple adverse health outcomes involving damage to pulmonary and cardiovascular tissue. Injury to pulmonary epithelium may include alterations in tight junction (TJ) integrity, resulting in impaired epithelial barrier function and enhanced penetration of chemicals and biomolecules. Herein, we investigated mechanisms involved in the disruption of TJ integrity by Cd exposure using an in vitro human air-liquid-interface (ALI) airway tissue model derived from normal primary human bronchial epithelial cells.

Methods

ALI cultures were exposed to noncytotoxic doses of CdCl₂ basolaterally and TJ integrity was measured by Trans-Epithelial Electrical Resistance (TEER) and immunofluorescence staining with TJ markers. PCR array analysis was used to identify genes involved with TJ collapse. To explore the involvement of kinase signaling pathways, cultures were treated with CdCl₂ in the presence of kinase inhibitors specific for cellular Src or Protein Kinase C (PKC).

Results

Noncytotoxic doses of CdCl₂ resulted in the collapse of barrier function, as demonstrated by TEER measurements and Zonula occludens-1 (ZO-1) and occludin staining. CdCl₂ exposure altered the expression of several groups of genes encoding proteins involved in TJ homeostasis. In particular, down-regulation of select junction-interacting proteins suggested that a possible mechanism for Cd toxicity involves disruption of the peripheral junctional complexes implicated in connecting membrane-bound TJ components to the actin cytoskeleton. Inhibition of kinase signaling using inhibitors specific for cellular Src or PKC preserved the integrity of TJs, possibly by preventing occludin tyrosine hyperphosphorylation, rather than reversing the down-regulation of the junction-interacting proteins.

Conclusions

Our findings indicate that acute doses of Cd likely disrupt TJ integrity in human ALI airway cultures both through occludin hyperphosphorylation via kinase activation and by direct disruption of the junction-interacting complex.     

Adenovirus-mediated transfer of the SOCS-1 gene to mouse lung confers protection against hyperoxic acute lung injury

Suppressor of cytokine signaling-1 (SOCS-1) is a member of the suppressor of cytokine signaling family of proteins and an inhibitor of interleukin-6 (IL-6) signaling. SOCS-1 has been shown to protect cells from cellular damage and apoptosis induced by tumor necrosis factor (TNF), lipopolysaccharide (LPS), and interferon gamma (IL-γ). However, it is not known whether increased SOCS-1 is protective during pulmonary oxidative stress. Therefore, we hypothesized that increased SOCS-1 in the lungs of mice would be protective in the setting of hyperoxic lung injury. We administered SOCS-1 adenovirus (Ad-SOCS-1) intratracheally into the lungs and exposed the mice to 100% O₂. Mice infected with GFP adenovirus (Ad-GFP) were used as controls. Mice treated with Ad-SOCS-1 had enhanced survival in 100% oxygen compared to Ad-GFP-administered mice. After 3 days of hyperoxia, Ad-GFP mice were ill and tachypnic and died after 4 days. In contrast, all Ad-SOCS-1-treated mice survived for at least 6 days in hyperoxia and 80% survived beyond 7 days. Ad-SOCS-1 transfection protected mouse lungs from injury as indicated by lower lung wet/dry weight, alveolar–capillary protein leakage, reduced infiltration of inflammatory cells, and lower content of thiobarbituric acid-reactive substances in lung homogenate. Our results also indicated that Ad-SOCS-1 significantly inhibits hyperoxia-induced ASK-1 (apoptosis signal-regulating kinase 1) expression. Taken together, these findings show that increased expression of adenovirus-mediated SOCS-1 in the lungs of mice significantly protects against hyperoxic lung injury.     

急性肺损伤的生物标记物

急性呼吸窘迫综合征(ARDS)和急性肺损伤(ALI)多由低氧性呼吸衰竭引起,导致高通透性肺水肿,临床上有较高的发病率与死亡率。近十年来,针对血浆和支气管肺泡灌洗液中相关生物标记物的研究为探索急性肺损伤的病理生理机制指明了新的方向。个别生物标记物已在一些大型、多中心ARDS试验中得到证实。但迄今仍没有一个或一组生物标记物常规应用于临床。随着人类对ALI发病机制理解的进一步深入,或许不久的将来,生物标记物会真正应用于评估疾病的严重程度和预后。本文将概述近年来ALI相关生物标记物的研究进展。     

ALI/ARDS患者使用保护性通气策略对于肺部损伤的影响

急性肺损伤(ALI)和急性呼吸窘迫综合征(ARDS)是常见的临床综合征,绝大多数ALI/ARDS患者需机械通气治疗,机械通气在提供可接受的肺部气体交换的同时治疗基础疾病,但机械通气本身也会引起肺部损伤,即机械通气性肺损伤(VILI)。而通过调整机械通气参数的设置,使用保护性通气策略可显著减低ALI/ARDS患者机械通气性肺损伤程度,从而减少肺部感染,缩短机械通气时间和住院时间,降低28天死亡率,明显改善ALI/ARDS患者的生存质量,起到最大程度地肺保护作用。本文从气道平台压,通气容积,呼气末正压等几个不同通气参数方面分别进行综述,讨论ALI/ARDS患者机械通气时使用保护性通气策略对于肺部损伤的影响。     

Surfactant Therapy for Patients with ARDS After Cardiac Surgery

This multicenter study investigated the possibility of reducing mortality rate by administering natural lung surfactant additional to standard therapy to treat patients after cardiac surgery who developed an acute respiratory failure (ARDS/ALI).

A total of 78 patients (1998–2002) diagnosed with ALI or ARDS were enrolled in the study; patients were considered for study entry only if they developed ALI/ARDS within 72h after cardiac surgery. A total of 36 patients (2000–2002) received Surfactant-BL via bronchoscope at a dose of 3 mg/kg twice a day, and 42 patients (1998–2000) served as the historical control.

Within 24h after the first Surfactant-BL administration the PaO₂/FiO₂ ratio increased from (mean ± SEM) 129.7 ± 9.9 mm Hg to 187.6 ± 17.6 mm Hg (p < 0.01), FiO₂ decreased from (mean ± SEM) 0.71 ± 0.03 to 0.56 ± 0.03 (p < 0.01), and 69.4% of the patients treated with surfactant were weaned from the ventilator compared with 50% of the control group during a 28-day period. The mortality rate among patients treated with Surfactant-BL was 30.6% compared with 50% in the control group.

In conclusion, early administration of Surfactant-BL leads to the reduction of mortality in cardiac patients who develop postoperatively an ALI or ARDS.     

原儿茶酸对脂多糖诱导的急性肺损伤小鼠的保护作用

目的:探索原儿茶酸(protocatechuicacid,PCA)对脂多糖(lipopolysaccharide,LPS)诱导的急性肺损伤(acute lung injury,ALI)小鼠的保护作用,探讨其保护机制。方法:将40只昆明小鼠按随机数字表法均分为空白对照组(NC组)、LPS模型组、原儿茶酸预处理组(PCA+LPS组)、地塞米松阳性对照组(Dex+LPS组),每组10只,模型组以5mg·kg-1脂多糖腹腔内注射诱导急性肺损伤。6h后处死小鼠,HE染色观察肺组织病理学变化;BCA法检测肺泡灌洗液中总蛋白浓度;ELISA检测肺泡灌洗液炎症因子TNF-α、IL-1β含量;Western Blot检测肺组织中p38MAPK、p-p38MAPK、p-ATF2蛋白的表达水平。结果:与对照组相比,模型组小鼠肺损伤明显,肺泡内出血、水肿、炎细胞浸润,肺泡灌洗液中TNF-α、IL-1β的含量及总蛋白浓度增加,肺组织中p38MAPK/p-p38MAPK、p-ATF2表达均明显增加(均P0.01)。与模型组相比,原儿茶酸预处理组、地塞米松阳性对照组肺组织病理损伤程度明显减轻,肺泡灌洗液中TNF-α、IL-1β的含量及总蛋白浓度、肺组织中p38MAPK/p-p38MAPK、p-ATF2表达均明显降低(均P0.01)。结论:PCA对LPS诱导的急性肺损伤有保护作用,其作用机制可能与其抑制p38MAPK-p-ATF2信号通路的活化、降低肺组织炎症反应有关。     

Maresin Conjugates in Tissue Regeneration 1 improves alveolar fluid clearance by up‐regulating alveolar ENaC,Na, K‐ATPase in lipopolysaccharide‐induced acute lung injury

Maresin Conjugates in Tissue Regeneration 1 (MCTR1) is a newly identified macrophage‐derived sulfido‐conjugated mediator that stimulates the resolution of inflammation. This study assessed the role of MCTR1 in alveolar fluid clearance (AFC) in a rat model of acute lung injury (ALI) induced by lipopolysaccharide (LPS). Rats were intravenously injected with MCTR1 at a dose of 200 ng/rat, 8 hours after administration of 14 mg/kg LPS. The level of AFC was then determined in live rats. Primary rat ATII (Alveolar Type II) epithelial cells were also treated with MCTR1 (100 nmol/L) in a culture medium containing LPS for 8 hours. MCTR1 treatment improved AFC (18.85 ± 2.07 vs 10.11 ± 1.08, P < .0001) and ameliorated ALI in rats. MCTR1 also significantly promoted AFC by up‐regulating epithelial sodium channel (ENaC) and Na⁺‐K⁺‐adenosine triphosphatase (Na, K‐ATPase) expressions in vivo. MCTR1 also activated Na, K‐ATPase and elevated phosphorylated‐Akt (P‐Akt) by up‐regulating the expression of phosphorylated Nedd4‐2 (P‐Nedd4‐2) in vivo and in vitro. However, BOC‐2 (ALX inhibitor), KH7 (cAMP inhibitor) and LY294002 (PI3K inhibitor) abrogated the improved AFC induced by MCTR1. Based on the findings of this study, MCTR1 may be a novel therapeutic approach to improve reabsorption of pulmonary oedema during ALI/acute respiratory distress syndrome (ARDS).     

Conditionally Reprogrammed Human Normal Airway Epithelial Cells at ALI: A Physiological Model for Emerging Viruses

Cancer cell lines have been used widely in cancer biology, and as biological or functional cell systems in many biomedical research fields. These cells are usually defective for many normal activities or functions due to significant genetic and epigenetic changes. Normal primary cell yields and viability from any original tissue specimens are usually relatively low or highly variable. These normal cells cease after a few passages or population doublings due to very limited proliferative capacity. Animal models(ferret, mouse, etc.) are often used to study virus-host interaction. However, viruses usually need to be adapted to the animals by several passages due to tropism restrictions including viral receptors and intracellular restrictions. Here we summarize applications of conditionally reprogrammed cells(CRCs), long-term cultures of normal airway epithelial cells from human nose to lung generated by conditional cell reprogramming(CR) technology, as an ex vivo model in studies of emerging viruses. CR allows to robustly propagate cells from non-invasive or minimally invasive specimens, for example, nasal or endobronchial brushing. This process is rapid(2 days) and conditional. The CRCs maintain their differentiation potential and lineage functions, and have been used for studies of adenovirus, rhinovirus, respiratory syncytial virus, influenza viruses, parvovirus, and SARS-CoV. The CRCs can be easily used for airliquid interface(ALI) polarized 3 D cultures, and these coupled CRC/ALI cultures mimic physiological conditions and are suitable for studies of viral entry including receptor binding and internalization, innate immune responses, viral replications, and drug discovery as an ex vivo model for emerging viruses.