Functional changes of pulmonary surfactant in rats with lung injury induced by endotoxin

We studied the functional changes of pulmonary surfactant （PS） in acutelung injury models produced by endotoxin injection (E.coli O55B5) in rats.The sur-face properties of the lung lavage liquid and the total phospholipids （TPL） ex-tracted from it were assessed on a modified Wilhelmy film balance.γ-A isothermof the lavage liquid revealed an increase in minimum surface tension and a de-crease in hysteresis area,recruitment index and stability index,whereas that ofTPL extracted from it did not show any change except for hysteresis area.Thesurface activity correlates positively with the TPL content but negatively with thetotal protein content in the lavage liquid.The findings indicated that there was adysfunction of PS in rats with the lung injury induced by endotoxin,suggestingthat the function deficiency of PS might be caused by decreased phospholipidsand increased proteins in the alveoli.

Extracellular vesicles in the pathogenesis and treatment of acute lung injury

Acute lung injury(ALI)and acute respiratory distress syndrome(ARDS)are common life-threatening lung diseases associated with acute and severe inflammation.Both have high mortality rates,and despite decades of research on clinical ALI/ARDS,there are no effective therapeutic strategies.Disruption of alveolar-capillary barrier integrity or activation of inflammatory responses leads to lung inflammation and injury.Recently,studies on the role of extracellular vesicles(EVs)in regulating normal and pathophysiologic cell activities,including inflammation and injury responses,have attracted attention.Injured and dysfunctional cells often secrete EVs into serum or bronchoalveolar lavage fluid with altered cargoes,which can be used to diagnose and predict the development of ALI/ARDS.EVs secreted by mesenchymal stem cells can also attenuate inflammatory reactions associated with cell dysfunction and injury to preserve or restore cell function,and thereby promote cell proliferation and tissue regeneration.This review focuses on the roles of EVs in the pathogenesis of pulmonary inflammation,particularly ALI/ARDS.

Drug repurposing of histone deacetylase inhibitors that alleviate neutrophilic inflammation in acute lung injury and idiopathic pulmonary fibrosis via inhibiting leukotriene a4 hydrolase and blocking LTB4 biosynthesis

OBJECTIVE Leukotriene B4(LTB4)biosynthesis and subsequently neutrophilic inflammation may provide a potential strategy for the treatment of acute lung injury(ALI)or idiopathic pulmonary fibrosis(IPF).To provide a potential strategy for the treatment of ALI or IPF,we identified potent inhibitors of Leukotriene A4 hydrolase(LTA4H),a key enzyme in the biosynthesis of LTB4.METHODS In this study,we identified two known histone deacetylase(HDAC)inhibitors,suberanilohydroxamic acid(SAHA)and its analogue 4-(dimethylamino)-N-[7-(hydroxyamino)-7-oxoheptyl]benzamide(M344),as effective inhibitors of LTA4H using enzymatic assay,thermofluor assay,and X-ray crystallographic investigation.We next tested the effect of SAHA and M344 on endogenous LTB4 biosynthesis in neutrophils by ELISA and neutrophil migration by transwell migration assay.A murine experimental model of ALI was induced by lipopolysaccharide(LPS)inhalation.Histopathological analysis of lung tissue using H&E staining revealed the serious pulmonary damage caused by LPS treatment and the effect of the SAHA.We next examined m RNA and protein levels of pro-inflammatory cytokines in lung tissue and bronchoalveolar lavage fluid using q RT-PCR and ELISA to further investigate the underlying mechanisms of anti-inflammatory activities by SAHA.We also investigated the effects of SAHA and M344 on a murine experimental model of bleomycin(BLM)-induced IPF model.RESULTS The results of enzymatic assay and X-ray crystallography showed that both SAHA and M344 bind to LTA4H,significantly decrease LTB4 levels in neutrophil,and markedly diminish early neutrophilic inflammation in mouse models of ALI and IPF under a clinical safety dose.CONCLUSION Collectively,SAHA and M344 would provide promising agents with well-known clinical safety for potential treatment in patients with ALI and IPF via pharmacologically inhibiting LAT4H and blocking LTB4 biosynthesis.

Alleviation of acute pancreatitis-associated lung injury by inhibiting the p38 mitogen-activated protein kinase pathway in pulmonary microvascular endothelial cells

BACKGROUND Previous reports have suggested that the p38 mitogen-activated protein kinase signaling pathway is involved in the development of severe acute pancreatitis(SAP)-related acute lung injury(ALI).Inhibition of p38 by SB203580 blocked the inflammatory responses in SAP-ALI.However,the precise mechanism associated with p38 is unclear,particularly in pulmonary microvascular endothelial cell(PMVEC)injury.AIM To determine its role in the tumor necrosis factor-alpha(TNF-α)-induced inflammation and apoptosis of PMVECs in vitro.We then conducted in vivo experiments to confirm the effect of SB203580-mediated p38 inhibition on SAP-ALI.METHODS In vitro,PMVEC were transfected with mitogen-activated protein kinase kinase 6(Glu),which constitutively activates p38,and then stimulated with TNF-α.Flow cytometry and western blotting were performed to detect the cell apoptosis and inflammatory cytokine levels,respectively.In vivo,SAP-ALI was induced by 5%sodium taurocholate and three different doses of SB203580(2.5,5.0 or 10.0 mg/kg)were intraperitoneally injected prior to SAP induction.SAP-ALI was assessed by performing pulmonary histopathology assays,measuring myeloperoxidase activity,conducting arterial blood gas analyses and measuring TNF-α,interleukin(IL)-1βand IL-6 levels.Lung microvascular permeability was measured by determining bronchoalveolar lavage fluid protein concentration,Evans blue pulmonary cells was confirmed by performing a terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling analysis and examining the Bcl2,Bax,Bim and cle-caspase3 levels.The proteins levels of P-p38,NFκB,IκB,P-signal transducer and activator of transcription-3,nuclear factor erythroid 2-related factor 2,HO-1 and Myd88 were detected in the lungs to further evaluate the potential mechanism underlying the protective effect of SB203580.RESULTS In vitro,mitogen-activated protein kinase(Glu)transfection resulted in higher apoptotic rates and cytokine(IL-1βand IL-6)levels in TNF-α-treated PMVECs.In vivo,SB2035080 attenuated lung histopathological injury,decreased inflammatory activity(TNF-α,IL-1β,IL-6 and myeloperoxidase)and preserved pulmonary function.Furthermore,SB203580 significantly reversed changes in the bronchoalveolar lavage fluid protein concentration,Evans blue accumulation,terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cell numbers,apoptosis-related proteins(cle-caspase3,Bim and Bax)and endothelial microstructure.Moreover,SB203580 significantly reduced the pulmonary P-p38,NFκB,P-signal transducer and activator of transcription-3 and Myd88 levels but increased the IκB and HO-1 levels.CONCLUSION p38 inhibition may protect against SAP-ALI by alleviating inflammation and the apoptotic death of PMVECs.

Liver cold preservation induce lung surfactant changes and acute lung injury in rat liver transplantation

AIM:To investigate the relationship between donor liver cold preservation,lung surfactant (LS) changes and acute lung injury (ALI) after liver transplantation.METHODS:Liver transplantation models were estab-lished using male Wistar rats.Donor livers were pre-served in University of Wisconsin solution at 4 ℃ for different lengths of time.The effect of ammonium pyr-rolidinedithiocarbamate (PDTC) on ALI was also detect-ed.All samples were harvested after 3 h reperfusion.The severity of ALI was evaluated by lung weight/body weight ratio,lung histopathological score,serum nitric oxide (NO) and endothelin (ET)-1 levels,lung tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels.Lung surfactants (LSs) were determined by micellar electrokinetic capillary chromatography.RESULTS:With extended donor liver cold preservation time (CPT),lung histopathological scores,serum ET-1 levels,lung weight/body weight ratio and the level of TNF-α and IL-1β in lung were increased significantly in the 180-min group compared with the sham group (3.16 ± 0.28 vs 1.12 ± 0.21,P < 0.001;343.59 ± 53.97 vs 141.53 ± 48.48,P < 0.001;0.00687 ± 0.00037 vs 0.00557 ± 0.00056,P < 0.001;17.5 ± 3.0 vs 1.3 ± 0.3,P < 0.001;10.8 ± 2.3 vs 1.8 ± 0.4,P < 0.001),but se-rum NO levels decreased remarkably (74.67 ± 10.01 vs 24.97 ± 3.18,P < 0.001).The expression of lung phos-phatidylcholine (PC),phosphatidylethanolamine (PE),phosphatidylinositol (PI) and phosphatidylserine (PS) increased when CPT was < 120 min,and decreased when CPT was > 180 min (PC:1318.89 ± 54.79 vs 1011.18 ± 59.99,P < 0.001;PE:1504.45 ± 119.96 vs 1340.80 ± 76.39,P=0.0019;PI:201.23 ± 34.82 vs 185.88 ± 17.04,P=0.2265;PS:300.43 ± 32.95 vs 286.55 ± 55.55,P=0.5054).All these ALI-associated indexes could be partially reversed by PDTC treatment.CONCLUSION:Prolonged CPT could induce or inhibit the expression of LSs at the compensation or decom-pensation stage,and some antioxidants (e.g.,PDTC) may reverse the pathological process partially.

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.

Effects of pulmonary stretch reflex on lung injury in rabbits with acute respiratory distress syndrome

BACKGROUND： Pulmonary stretch reflex plays an important role in regulation of respiratorymovement. This study aimed to evaluate the effect of pulmonary stretch reflex on lung injury inrabbits with acute respiratory distress syndrome （ARDS）.METHODS： ARDS rabbits were given intratracheal infusion of hydrochloric acid and ventilatedwith neurally adjusted ventilatory assistance （NAVA） with a tidal volume （VT） of 6 mL/kg and theelectrical activity of diaphragm （EAdi）-determined positive end expiratory pressure. After isolation ofthe bilateral vagus nerve trunk, the rabbits were randomized into two groups： sham operation （SHAM）group （n=5） and bilateral vagotomy （VAG） group （n=5）. Gas exchange and respiratory mechanicswere detected at baseline, after lung injury and 1, 2, and 3 hours after ventilation respectively.Pulmonary permeability index, pathological changes and infl ammatory response were also measured.RESULTS： Compared with the SHAM group, PaO2/FiO2 in the VAG group decreased signifi cantly2 and 3 hours after ventilation （P〈0.05）. There was no significant difference in PaCO2 betweenthe SHAM and VAG groups （P〉0.05）, and the VAG group had a high VT, peak pressure （Ppeak）,and mean pressure （Pm） compared with the SHAM group 1, 2, 3 hours after ventilation （P〈0.05）.Compared to the SHAM group, dead space fraction （VD/VT） and respiratory system elastance （Ers）in the VAG group increased （P〈0.05） and static pulmonary compliance （Cst） decreased markedly（P〈0.05） after ventilation for 3 hours. Lung wet/dry weight ratio （W/D） （8.4±1.2 vs. 6.6±1.0）, lung injuryscore （6.3±1.8 vs. 3.8±1.3）, tumor necrosis factor-# （TNF-#） （779±372 pg/mL vs. 355±130 pg/mL）and interleukin-8 （IL-8） （169±21 pg/mL vs. 118±17 pg/mL） increased significantly in the VAG groupcompared with the SHAM group （P〈0.05）.CONCLUSION： Lung injury is aggravated after bilateral vagotomy, demonstrating thatpulmonary stretch refl ex may have protective effect on the lung.

Successful Extracorporeal Membranous Oxygenation with Possible Transfusion-Related Acute Lung Injury after Pulmonary Endarterectomy

Transfusion-related acute lung injury (TRALI) is characterized by acute severe hypoxemia with bilateral noncardiogenic pulmonary edema after transfusion of a plasma-containing blood component. In patients undergoing cardiac surgery, the incidence of TRALI is high;however, the detailed clinical course is unknown. Here, we report a case of life-threatening TRALI following pulmonary thrombectomy, which was successfully treated with extracorporeal membranous oxygenation (ECMO).

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.

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.

Acute lung injury and acute respiratory distress syndrome： experimental and clinical investigations

尖锐的肺损害(所有) 或尖锐呼吸悲痛症候群(ARDS ) 能与各种各样的混乱被联系。最近的调查在各种各样的混乱引起的 ALI 或 ARDS 的病原的机制上与临床的调查者和病理学家合作包含了临床的研究。这文学评论包括一篇摘要历史 ALI/ARDS 回顾，神经原的肺的浮肿由于从我们的实验室的头损害，长期的试验性的研究和临床的调查，有害角色没有，风险因素，和象为 ALI/ARDS 的治疗学的政体一样的可能的病原的机制。

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.

Acute lung injury mechanism and therapy induced by paraquat poisoning

Paraquat (PQ, methyl viologen) was widely used in agricultural production throughout the world in 1962 for its efficient herbicidal activity. PQ was also highly toxic drug. About 5 mL medicine including 20% paraquat was life-threatening that can cause poisoning. In 1966, some people died because of PQ poisoning. Most patients had acute respiratory distress syndrome after 2 wk, and 70% of them died due to the lack of effective detoxification drugs. Thus, it was particularly important to understand the pathogenesis of PQ poisoning and give some effective treatments. This article will review the toxicological mechanism and treatment on PQ poisoning of acute lung injury.

Basic and clinical research progress in acute lung injury/acute respiratory distress syndrome

Acute lung injury(ALI)/acute respiratory distress syndrome(ARDS) is an acute progressive respiratory failure caused by severe infection, trauma, shock, poisoning, inhaled harmful gas, acute pancreatitis, and pathological obstetrics. ALI and ARDS demonstrate similar pathophysiological changes. The severe stage of ALI is defined as ARDS. At present, a significant progress has been achieved in the study of the pathogenesis and pathophysiology of ALI/ARDS. Whether or not ALI/ARDS patients can recover depends on the degree of lung injury, extra-pulmonary organ damage, original primary disease of a patient, and adequacy in supportive care. Conservative infusion strategies and protective lung ventilation reduce ARDS disability and mortality. In this study, the pathogenesis of ALI/ARDS, lung injury, molecular mechanisms of lung repair, and conservative infusion strategies and pulmonary protective ventilation are reviewed comprehensively.

GSN antibody pretreatment aggravates radiation-induced lung injury in mice

Radiation-induced lung injury is one of the main dose limiting factors for thoracic radiation therapy.Gelsolin(GSN) is a widespread,multifunctional regulator of cellular structure and metabolism.In this work,the roles of GSN in radiation-induced lung injury in Balb/c mice were studied.The GSN levels in plasma reduced progressively in 72 hours after irradiation,and then increased gradually.GSN contents in the bronchoalveolar lavage(BAL) fluid increased after thoracic irradiation,whereas mRNA levels of GSN in the lung tissue decreased significantly within 24 hours after irradiation and then increased again.Mice were intravenously injected with 50 ug GSN antibody 0.5 hour before 20 Gy of thoracic irradiation.GSN antibody pretreatment increased lung inflammation,protein concentration in the BAL fluid and leukocytes infiltration in the irradiated mice.The activities of superoxidase dismutase(SOD) in the plasma and the BAL fluid in irradiated mice injected with GSN antibody were less than that of control groups,whereas the levels of malondialdehyde(MDA)increased.These results suggest that pretreatment of GSN antibody may aggravate radiation-induced pneumonitis.

Effects of continuous tracheal gas insufflation during pressure limited ventilation on pulmonary surfactant in rabbits with acute lung injury

Background Pulmonary surfactant dysfunction may contribute to the development of ventilator induced lung injury （VILI）. Tracheal gas insuffiation （TGI） is a technique in which fresh gas is introduced into the trachea and augment ventilation by reducing the dead space of ventilatory system, reducing ventilatory pressures and tidal volume （VT） while maintaining constant partial arterial CO2 pressure （PaCO2）. We hypothesised that TGI limited peak inspiratory pressure （PIP） and VT and would minimize conventional mechanical ventilation （CMV） induced pulmonary surfactant dysfunction and thereby attenuate VILI in rabbits with acute lung injury （ALI）. Methods ALI was induced by intratracheal administration of lipopolysaccharide in anaesthetized, ventilated healthy adult rabbits randomly assigned to continuous TGI at 0.5 L/min （TGI group） or CMV group （n=8 for each group）, and subsequently ventilated with limited PIP and VT to maintain PaCO2 within 35 to 45 mmHg for 4 hours. Physiological dead space to VT ratio （VD/VT）, dynamic respiratory compliance （Cdyn） and partial arterial O2 pressure （PaO2） were monitored. After ventilation, lungs were analysed for total phospholipids （TPL）, total proteins （TP）, pulmonary surfactant small to large aggregates ratio （SA/LA） in bronchoalveolar lavage fluid （BALF） and for determination of alveolar volume density （Vv）, myeloperoxidase and interleukin （IL）-8. Results TGI resulted in significant （P〈0.05 or P〈0.01） decrease in PIP [（22.4±1.8） cmH20 vs （29.5±1.1） cmH2O], VT [（6.9±1.3） ml/kg vs （9.8±1.11） ml/kg], VD/VT [（32±5）% vs （46±2）%], TP [（109±22） mg/kg vs （187±25） mg/kg], SA/LA （2.5±0.4 vs 5.4±0.7）, myeloperoxidase [（6.2±0.5） U/g tissue vs （12.3±0.8） U/g tissue] and IL-8 [（987±106） ng/g tissue vs （24±3） mN/m] of BALF, and significant （P〈0.05） increase in Cdyn [（0.47±0.02） ml·cmH2O^-1·kg^-1 vs （0.31±0.02） ml·cmH2O^-1·kg^-1], PaO2 [（175±24） mmHg vs （135±26） mmHg], TPL/TP （52±8 vs 33±11） and Vv （0.65±0.05 vs 0.44±0.07） as compared with CMV. Conclusions In this animal model of ALI, TGI decreased ventilatory requirements （PIP, VT and VD/VT）, resulted in more favourable alveolar pulmonary surfactant composition and function and less severity of lung injury than CMV. TGI in combination with pressure limited ventilation may be a lung protective strategy for ALI.

氢气在呼吸系统疾病中的作用及研究进展

氢气是一种无色无味、具有生物活性的还原性小分子气体,具有抗炎、抗氧化、抗凋亡等生物学功能,可用于多种疾病的辅助治疗。人们使用氢的方式已不局限于氢气吸入,还出现了氢水饮用、含氢溶液注射、含氢透析液透析等新方法,氢的生物学作用得到广泛关注。本文围绕氢气在慢性阻塞性肺疾病、哮喘、肺癌、新型冠状病毒感染、急性肺损伤、肺纤维化等呼吸系统疾病中的作用及研究进展进行讨论。

基于共聚焦激光显微内镜的海水淹溺肺损伤大鼠肺通透性的实时活体评价

背景急性肺损伤是临床常见急危重症,其核心病理特征是气血屏障的破坏,目前对肺损伤中气血屏障结构及功能改变进行活体评估的研究甚少。目的使用共聚焦激光显微内镜实现大鼠肺的在体可视化成像和海水淹溺肺损伤大鼠肺通透性的实时动态活体评估。方法10只SD大鼠随机分为对照组和海水淹溺(seawater drowning,SW)组,每组5只;SW组通过气管滴注人工海水建立海水淹溺肺损伤模型,造模后3 h进行肺活体观察窗开窗手术,4 h时经股静脉推注0.2 mL异硫氰酸荧光素-葡聚糖(10 mg/mL);对照组不进行海水滴注,其余操作同SW组。使用共聚焦激光显微内镜对右肺下叶进行30 min活体观察,对成像0 min、10 min、20 min、30 min时的共聚焦图像进行染料渗漏指数及荧光分布均匀程度的分析;成像结束后处死大鼠,取肺组织、外周血及肺泡灌洗液,进行组织病理学检查、FITC-Dextran渗漏量检测、肺泡灌洗液蛋白含量检测及肺组织湿/干比测定。结果经静脉给予FITC-Dextran后,共聚焦激光显微内镜下可观察到肺微循环和肺泡结构的实时图像;对照组血管及肺泡结构较清晰,未出现血管外空间荧光强度的明显增加,而SW组血管结构随时间推移逐渐模糊,各时间点SW组的渗漏指数均高于对照组(P<0.05),10 min、20 min、30 min时荧光分布的变异系数均低于对照组(P<0.05);SW组的染料渗漏量、肺泡灌洗液蛋白含量及肺组织湿/干比均高于对照组(P<0.05)。结论海水淹溺造成大鼠肺组织结构破坏,肺通透性增加;利用共聚焦激光显微内镜可实现大鼠肺组织结构的在体可视化成像,通过对共聚焦图像的定量分析,还可实现大鼠气血屏障通透性的实时活体评估。

MIRO1修饰的人脐带间充质干细胞通过线粒体自噬修复肺上皮细胞损伤的实验研究

背景间充质干细胞(mesenchymal stem cells,MSCs)为急性肺损伤(acute lung injury,ALI)的治疗修复提供了新的策略,目前单独的MSCs治疗效果欠佳,需要探索增强MSCs疗效的方法。目的探讨过表达MIRO1(mitochondrial Rho GTPase 1,Rhot1)的人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,hUCMSCs)对脂多糖诱导的人肺支气管上皮细胞(bronchial epithelium transformed with Ad12-SV402B,BEAS-2B)损伤的治疗作用。方法包装过表达MIRO1的慢病毒,通过慢病毒感染构建过表达MIRO1的hUCMSCs稳转细胞株;实验细胞随机分为4组:对照组(Control)、脂多糖组(LPS)、脂多糖+人脐带间充质干细胞组(Con-hUCMSCs)、脂多糖+过表达MRIO1的人脐带间充质干细胞组(MIRO1-hUCMSCs)。脂多糖刺激BEAS-2B细胞24 h,通过Transwell小室分别与Con-hUCMSCs和MIRO1-hUCMSCs细胞共培养24 h,收集BEAS-2B细胞并使用Western blot和RT-qPCR实验方法检测肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)、白细胞介素1β(interleukin,IL-1β)、IL-6和线粒体自噬相关蛋白(PINK1、PARKIN、MIRO1、SQSTM1)表达水平。结果成功筛选获得过表达MIRO1的hUCMSCs稳转细胞株。通过Transwell小室共培养,MIRO1-hUCMSCs组可抑制脂多糖组炎症因子TNF-α、IL-1β和IL-6的升高(P<0.05),恢复线粒体自噬蛋白PINK1、SQSTM1、MIRO1的低表达(P<0.05),降低PARKIN蛋白高表达(P<0.05)。MIRO1-hUCMSCs组相比LPS组、Con-hUCMSCs组治疗有统计学差异(P<0.05)。结论MIRO1修饰的hUCMSCs与单纯hUCMSCs相比,可通过调节线粒体自噬PINK1-Parkin通路中的PINK1、PARKIN、MIRO1和SQSTM1蛋白改善脂多糖引起的BEAS-2B细胞损伤。