Lung Tissue Water Content Research Articles

Preliminary screening of biomarkers in HAPE based on quasi-targeted metabolomics.

High altitude pulmonary edema (HAPE) is a serious threat to the physical and mental health of people who quickly enter high plateaus, deserves more attention and in-depth research. In our study, through the detection of various physiological indexes and other phenotypes in a HAPE rat model, the HAPE group showed a significant decrease in oxygen partial pressure and oxygen saturation, and a significant increase in pulmonary artery pressure and lung tissue water content. The lung histomorphology showed characteristics such as pulmonary interstitial thickening and inflammatory cell infiltration. We applied quasi-targeted metabolomics to compare and analyze the components of metabolites in arterial-veinous blood in control rats and HAPE rats. Using kyoto Encyclopedia of Genes Genomes (KEGG) enrichment analysis and two machine algorithms, we speculate that after hypoxic stress and comparing arterial blood and venous blood products in rats, the metabolites were richer, indicating that normal physiological activities, such as metabolism and pulmonary circulationhad a greater impact after hypoxic stress; D-mannoseDOWN, oxidized glutathioneDOWN, glutathione disulfideDOWN, and dehydrocholic acidDOWN in arterial blood play key roles in predicting the occurrence of HAPE; in venous blood, L-leucineDOWN, L-thyroxineDOWN, and cis-4-hydroxy- D-prolineDOWN may have key roles, which can be considered biomarkers of HAPE. This result provides a new perspective for the further diagnosis and treatment of plateau disease and lays a strong foundation for further research.

Activation of cannabinoid receptor 2 alleviates acute lung injury in rats with lipopolysaccharide-induced sepsis

To investigate the protective effect of cannabinoid receptor 2 (CB2) activation against acute lung injury in rats with lipopolysaccharide (LPS)-induced sepsis and explore the underlying mechanism. Forty-eight SD rats were randomly assigned into control group, model group, CB2 agonist group and P38 MAPK inhibitor group (n=12). In the latter 3 groups, the rats received intraperitoneal injection of LPS to induce sepsis, and the control rats were given saline injection. In CB2 agonist group, JWH133 (3 mg/kg) was injected intraperitoneally 30 min before LPS injection; in P38 MAPK inhibitor group, the rats received intraperitoneal injection of SB203580 (5 mg/kg) 30 min prior to JWH133 injection. The changes in lung histopathology, water content, fluid clearance rate, inflammatory factors, pulmonary expressions of CB2 and tight junctionrelated genes, and phosphorylation of P38 MAPK in the lung tissues were examined. The rat models of sepsis showed severe damage of alveolar structures with significantly decreased fluid clearance rate, lowered pulmonary expressions of CB2, occludin and ZO-1 mRNA and proteins, increased water content in the lung tissue, and increased phosphorylation level of P38 MAPK and TNF-α and IL-1β levels in lung lavage fluid (all P < 0.05). Treatment with JWH133 improved alveolar pathology in the septic rats, but there was still inflammatory infiltration; lung tissue water content, phosphorylation of P38 MAPK, and TNF-α and IL-1β levels in lung lavage fluid were all significantly decreased, and the fluid clearance rate, pulmonary expressions of CB2, occludin and ZO-1 were significantly increased (all P < 0.05). Additional treatment with SB203580 resulted in further improvements of alveolar pathologies, lowered phosphorylation levels of P38 MAPK in the lung tissue and TNF-α and IL-1β levels in lung lavage fluid, and increased the protein expressions of occludin and ZO-1 (P < 0.05) without causing significant changes in mRNA and protein expression of CB2 (P > 0.05). In rats with LPS-induced sepsis, activation of CB2 can inhibit the p38 MAPK signaling pathway, reduce the release of inflammatory factors in the lung tissues, promote tight junction protein expressions, and thus offer protection against acute lung injury.

Taraxasterol Inhibits Hyperactivation of Macrophages to Alleviate the Sepsis-induced Inflammatory Response of ARDS Rats.

To explore the effect and mechanism of taraxasterol on sepsis-induced acute respiratory distress syndrome (ARDS). Twenty-four male SD rats were randomly divided into four groups: the control group, model (lipopolysaccharide, LPS) group, lipopolysaccharide+taraxasterol (LPS + TXL) group, and lipopolysaccharide+ulinastatin (LPS + UTI) group. The model of sepsis-induced ARDS was established by intraperitoneal injection of LPS. The lung water content of the rats in each group was determined by the dry/wet ratio. Pathology of rat lung tissue was observed through H&E staining. Wright staining was applied to count the number of neutrophils, macrophages, and total cells. ELISA was utilized to measure the levels of the inflammatory factors TNF-α, IL-1β, and IL-6 in bronchoalveolar lavage fluid (BALF). Biochemical detection was adopted to check the levels of myeloperoxidase (MPO), superoxide dismutase (SOD) and catalase (CAT) in lung tissue. Western blotting was performed to check the protein expression of IL-12, iNOS, Arg-1, and Mrc1 in lung tissue. Compared with the LPS group, both taraxasterol and ulinastatin significantly decreased lung tissue water content, improved lung tissue injury, reduced the number of neutrophils, macrophages and total cells, and decreased the level of inflammatory factors. In addition, taraxasterol and ulinastatin also reduced the content of MPO and the expression of IL-12 and iNOS and increased the activity of SOD and CAT as well as the protein expression of Arg-1 and Mrc1. Taraxasterol can suppress macrophage M1 polarization to alleviate the inflammatory response and oxidative stress, thereby treating sepsis-induced ARDS.

Role and mechanism of signal transducer and activator of transcription protein STAT1/3/5 in hyperoxia-induced acute lung injury

To investigate whether signal transducer and activator of transcription (STAT1/3/5) have a protective effect on hyperoxia-induced acute lung injury (HALI) and its mechanism. Seventy C57BL/6J mice were randomly divided into five groups: normoxia control group, HALI group, and STAT1/3/5 inhibitor groups, with 14 mice in each group. The HALI model was established by exposure to more than 90% hyperoxia for 48 hours; three STAT inhibitor groups were pretreated by intraperitoneal injection of STAT1 inhibitor 40 mg/kg and STAT3 inhibitor 5 mg/kg, and STAT5 inhibitor 10 mg/kg for 1 week. Six blood samples were randomly collected from each group, and microRNA-21 (miR-21) expression was measured by quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR). Lung tissue of the sacrificed mice was obtained, and enzyme linked immunosorbent assay (ELISA) was used to detect the contents of tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-1β), superoxide dismutase (SOD), malonic dialdehyde (MDA), and matrix metalloproteinase 9 (MMP9). The water content of lung tissue was calculated. The pathological changes in lung tissue were observed under the light microscope, and the pathological score of lung injury was performed. Western blotting was used to detect the expression of phosphorylated STAT (p-STAT1, p-STAT3, p-STAT5) in lung tissue. The 7-day cumulative survival rates of the remaining 8 mice in each group were analyzed using Kaplan-Meier survival curves. Under the light microscope, the alveolar structures in the HALI group and the STAT1 inhibitor group were destroyed, a large number of neutrophils (NEU) infiltrated in the alveoli and lung interstitium, which were thickened. The pathological score of lung injury and the water content of the lung tissue was significantly increased. In STAT3 inhibitor and STAT5 inhibitor groups, the alveolar cavity was clear, the degree of NEU infiltration and the thickness of lung interstitium were lower than those in HALI group, the pathological score of lung injury and the water content of lung tissue were significantly decreased, especially in STAT3 inhibitor group. Compared with the normoxia control group, the contents of TNF-α, IL-6, IL-1β, MDA, and MMP9, and the expression levels of p-STAT3 and p-STAT5 in the HALI group were significantly increased. In contrast, the content of SOD and the expression of miR-21 were significantly decreased. Compared with the HALI group, the contents of TNF-α, IL-6, IL-1β, MDA, and MMP9 in the STAT3 inhibitor group and STAT5 inhibitor group were significantly decreased. At the same time, the content of SOD and the expression of miR-21 were significantly increased, especially in STAT3 inhibitor group [TNF-α (μg/L): 42.53±3.25 vs. 86.36±5.48, IL-6 (ng/L): 68.46±4.28 vs. 145.00±6.89, IL-1β (μg/L): 28.74±3.53 vs. 68.00±5.64, MDA (μmol/g): 20.33±2.74 vs. 42.58±3.45, and MMP9 (ng/L): 128.55±6.35 vs. 325.13±6.65, SOD (kU/g): 50.53±4.19 vs. 22.53±3.27, miR-21 (2-ΔΔCt): 0.550±0.018 vs. 0.316±0.037, all P < 0.05]. Kaplan-Meier survival curve analysis showed that the 7-day cumulative survival rates of the STAT3 inhibitor group and STAT5 inhibitor group were significantly higher than those of the HALI group [62.5% (5/8), 37.5% (3/8) vs. 12.5% (1/8), both P < 0.05]. Inhibition of STAT3 hyperactivation may suppress the inflammatory response, regulate oxidative stress, improve lung permeability through regulating the expression of miR-21, which exert lung protection in HALI.

Role and mechanisms of MLKL-NLRP3-mediated necroinflammation in mice with sepsis-induced acute lung injury

To investigate the roles and underlying mechanisms of mixed lineage kinase domain like (MLKL)-mediated inflammatory response induced by NOD-like receptor protein 3 (NLRP3) inflammatory corpuscles in the acute lung injury (ALI) after sepsis. Eighteen BALB/c mice were randomly divided into sham operation group (Sham group), cecal ligation and perforation (CLP)-induced sepsis model group (CLP group) and specific inhibitor Necrostatin-1 intervention group [CLP+Nec-1 group, Necrostatin-1 solution (20 mg/kg) was injected intravenously 10 minutes before modeling], with 6 mice in each group. The mice were sacrificed by neck amputation at the 2nd day after operation, and the serum and lung tissue samples were collected. The morphological changes of lung tissue were observed by hematoxylin-eosin (HE) staining. The water content of lung tissue was detected by dry-wet weight method. The pulmonary vascular permeability was measured by Evans blue (EB) staining. The protein expressions of MLKL and NLRP3 in the lung tissue were detected by Western blotting, and the level of serum interleukin-1β (IL-1β) was detected by enzyme linked immunosorbent assay (ELISA). HE staining showed that the lung morphological structure in Sham group was normal. In CLP group, congestion and edema in the alveolar cavity and interstitium, infiltration of neutrophils and thickening of alveolar wall were observed. The histopathological changes of lung tissue in CLP+Nec-1 group were better than those in CLP group. Compared with Sham group, the water content of lung tissue [(88.00±0.00)% vs. (78.00±0.01)%], pulmonary vascular permeability [EB content (mg/L): 11.82±1.15 vs. 4.00±0.71], the protein expressions of phosphorylated MLKL (p-MLKL) and NLRP3 in lung tissue (p-MLKL/GAPDH: 0.34±0.04 vs. 0.12±0.01,NLRP3/GAPDH: 0.47±0.07 vs. 0.16±0.04), and the level of serum IL-1β (ng/L: 183.56±9.61 vs. 44.14±6.95) in CLP group were all significantly increased (all P < 0.01). Compared with CLP group, the water content of lung tissue [(81.00±0.01)% vs. (88.00±0.00)%], pulmonary vascular permeability [EB content (mg/L): 7.90±0.00 vs. 11.82±1.15], protein expressions of p-MLKL and NLRP3 in lung tissue (p-MLKL/GAPDH: 0.13±0.03 vs. 0.34±0.04, NLRP3/GAPDH: 0.18±0.04 vs. 0.47±0.07), and the level of serum IL-1β (ng/L: 113.81±6.62 vs. 183.56±9.61) were all significantly decreased (all P < 0.01). MLKL-NLRP3-mediated necroinflammation was significantly up-regulatedin the lung tissue of septic mice, which could be attenuated by specific inhibitor Necrostatin-1.

Interleukin IL-5 alleviates sepsis-induced acute lung injury by regulating the immune response in rats

ABSTRACT To study the effect of IL-5 on the immune response and lung injury in rats with sepsis. We constructed a rat model of sepsis by cecal ligation and puncture (CLP). The rats were randomly divided into the control group, the sham group, the CLP group and the IL-5 group, with 6 rats in each group. With the induction of CLP, the lung tissue of rats was severely injured, and the water content of lung tissue was significantly increased. Moreover, the ratio of CD4+/CD8+ was significantly decreased and Th1/Th2 was significantly increased in the peripheral blood. The content of IL-6, TNF-α, and HMGB1 was found to be increased in the CLP group. However, with the injection of IL-5, the degree of lung tissue injury in CLP rats was alleviated and the water content of lung tissue was significantly reduced. The ratio of CD4+/CD8+ was increased and Th1/Th2 was significantly down-regulated in the peripheral blood and the levels of IL-6, TNF-α, and HMGB1 in serum were significantly decreased. In conclusion, IL-5 can alleviate lung injury by regulating the immune response and inhibiting the systemic inflammatory response induced by sepsis.

P6377Cardiopulmonary effects of nitric oxide supplementation in a model of chronic hypoxia pulmonary hypertension

Abstract Objective We previously demonstrated that the inhibition of phosphodiesterase type-5, an enzyme that degrades cGMP into inactive 5'-GMP, attenuates pulmonary remodeling and right ventricular (RV) hypertrophy (RVH) during exposure to chronic hypoxia (CH). The nitric oxide (NO) pathway is thought to play a major role in these changes. In this study, we investigate whether L-Arginine (L-ARG), a substrate of endothelial NO synthase (eNOS) and molsidomine (MOL), a NO donor, might alleviate the cardiovascular and pulmonary dysfunction led by CH. Methods Male rats (n=80; 10/group) were maintained in normoxic (21% O2) or hypoxic chambers (10% O2) for 14 days. Hypoxic rats were subdivided in four groups: untreated control, treated with L-ARG (45 mg/kg), eNOS inhibitor N-nitro-L-arginine methyl ester (L-NAME, 45 mg/kg) or MOL (15 mg/kg). Drugs were given daily in the drinking water. After sacrifice, we measured RV systolic pressure (RVSP), RV contractility (dP/dt), RVH, the lung/body weight ratio, the pulmonary vessels medial wall thickness, and the cardiac and pulmonary eNOS phosphorylation. Results Although CH increased RVSP, RV contractility and RVH, these increases were attenuated by L-ARG and MOL. Whereas L-ARG attenuated the RVH increase, MOL and L-NAME were ineffective. No treatment prevented the increase in lung/body weight ratio. Under all conditions, the lung tissue water content was unchanged, indicating no edema development. By contrast, CH rats developed a marked increase in medial wall thickness of small (0–100 mm) pulmonary arteries, while larger arteries were not affected. This increase was attenuated by L-ARG or MOL. Although CH decreased cardiac and pulmonary phosphorylated eNOS, L-ARG and MOL restored the normoxic level. Conclusions NO supplementation during CH attenuates RVSP, RVH and pulmonary remodeling, probably due to increased phosphorylation of eNOS. Despite normalizing RVSP, MOL does not influence RVH development.

Effect of anisodamine on lung edema after ischemia-reperfusion in rabbits

Objective To investigate the protective efficacy of anisodamine against lung edema after ischemia-reperfusion in rabbits,and to explore the possible mechanism.Methods In vivo lung ischemia-reperfusion model of rabbit was developed. Twenty-four Chinese rabbits of either gender,aged 10-12 weeks,weighing 2200-2600 g,were divided into 3 groups randomly:anisodamine group,control group and sham group,with 8 rabbits in each group.In anisodamine group,the left pulmonary hilum was occluded for 1 hour and then released for 3 hours,and anisodamine(3 mg/kg) was given by intravenously injection before occlusion. In control group,only ischemia-reperfusion was performed.In sham group,left lung received no ischemia-reperfusion.Left lung tissue in each group was harvested for histopathological analysis,lung water content determination and myeloperoxidase(MPO) level detection.Also,2%Evens blue(1.5 ml/kg) was injected into femoral venous to measure lung vascular permeability.Results After ischemia-reperfusion,the lung tissue water content,MPO level and Evens blue level in control group were(6.6±0.5) g/g dry tissue, (1.16±0.14) U/g protein and(173±16) ug/g wet tissue respectively,significantly higher than those in sham group[(4.3±0.4) g/g dry tissue,(0.53±0.09) U/g protein and(103±11)μg/g wet tissue,P0.05].These indices in anisodamine group were(5.6±0.4) g/g dry tissue,(0.82±0.11)U/g protein and(124±18)μg/g wet tissue,obviously lower than those in control group(P0.05).Left lung displayed prominent edema,septal swelling,hemorrhage and neutrophil infiltration in control group,while which was significantly improved in anisodamine group.Conclusion Anisodamine can significantly prevent lung edema after ischemia-reperfusion in rabbits. The mechanism may be ascribed to inhibition of neutrophil infiltration and decrease in vascular permeability.

Transitory Blocking of Pulmonary Artery and Veins as a Novel Strategy in Pulmonary Surgery: An Experimental Study in a Rabbit Model

Backgrounds: Transitory blocking of the pulmonary artery and veins is now being applied in the treatment of local advanced non-small cell lung cancer in our department. We performed this study to establish a pulmonary vessel blocking model in rabbits and investigate the features of lung ischemia-reperfusion injury. Methods: 126New Zealand rabbits were randomized into 3 groups: group I, sham group; group II, left pulmonary artery blocking, and group III, left pulmonary artery and veins blocking. The physiological data as well as the blood and tissue samples were harvested at the time of thoracotomy, at 1 h after ischemia and 1, 2, 4, 6 and 24 h after reperfusion, respectively. Lung injury was assessed histologically by determining the levels of malondialdehyde, superoxide dismutase, myeloperoxidase and water content. Results: The hemodynamics were stable in all three groups. The levels of malondialdehyde, myeloperoxidase, and water content of lung tissue were all significantly increased in groups II and III when compared with group I at 1, 2, 4 and 6 h after reperfusion. They almost all returned to baseline at 24 h after reperfusion. However, there was no significant difference observed between groups II and III at either time point. A similar change in the process of lung ischemia-reperfusion injury was observed under light and electron microscopes in group II and in group III. Conclusions: The features of lung ischemia-reperfusion injury were similar when blocking the pulmonary artery and veins compared with blocking the pulmonary artery alone. Moreover, it might be safe to block the pulmonary vessels within 1 h during pulmonary surgery.

NOVEL OVINE MODEL OF METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS-INDUCED PNEUMONIA AND SEPSIS

Methicillin-resistant Staphylococcus aureus (MRSA)-related pneumonia and/or sepsis are a frequent serious menace. The aim of the study was to establish a standardized and reproducible model of MRSA-induced septic pneumonia to evaluate new therapies. Sheep were operatively prepared for chronic study. After 5 days' recovery, tracheostomy was performed under anesthesia, and smoke injury was induced by inhalation of cotton smoke (48 breaths, <40 degrees C). Methicillin-resistant S. aureus (AW6) (approximately 2.5x10(11) colony-forming units) was instilled into the airway by a bronchoscope. After the injury, animals were awakened and maintained on mechanical ventilation by 100% oxygen for first 3 h, and thereafter, oxygen concentration was adjusted according to blood gases. The sheep were resuscitated by lactated Ringer solution with an initial rate of 2 mL kg(-1) h(-1) that was further adjusted according to hematocrit. Study groups include (1) sham (noninjured, nontreated; n=6), (2) S+MRSA (exposed to smoke inhalation and MRSA, nontreated; n=6), and (3) smoke (exposed to smoke inhalation alone; n=6). Injured (S+MRSA) animals showed the signs of severe sepsis-related multiple organ failure 3 h after insult. Cardiovascular morbidity was evidenced by severe hypotension, with increased heart rate, cardiac output, left atrial pressure and severely decreased systemic vascular resistance index, and left ventricle stroke work index. Pulmonary dysfunction was characterized by deteriorated gas exchange (PaO2/FIO2 and pulmonary shunt) and increased ventilatory pressures. The S+MRSA group showed significantly greater lung tissue water content, myeloperoxidase activity, and cytokine production compared with uninjured sham animals. Microvascular hyperpermeability was evidenced by marked fluid retention (fluid net balance), decreased plasma protein with decreased plasma oncotic pressure, and increased pulmonary microvascular pressure. All these changes were accompanied by 6- to 7-fold increase in plasma nitrite/nitrate and increased production of reactive nitrogen species in lung. The smoke inhalation alone had a little or no effect on these variables. This model closely mimics hyperdynamic human sepsis. The excessive production of NO may be extensively involved in the pathogenic process.

Glycine intravenous donor preconditioning is superior to glycine supplementation to low-potassium dextran flush preservation and improves graft function in a large animal lung transplantation model after 24 hours of cold ischemia

The potential role of glycine in combination with standard lung preservation with low-potassium dextran solution in lung ischemia-reperfusion injury has not been investigated in a preclinical porcine transplant model. In a control group (n = 6), donor lungs were flushed with 1 liter of low-potassium dextran solution. In a second group (LPD-glyc, n = 6), low-potassium dextran solution was supplemented with 3.75 g of glycine. In a third group (IV-glyc, n = 6), donor preconditioning was performed by intravenous administration of 3.75 g glycine 1 hour before low-potassium dextran preservation. Grafts were stored in low-potassium dextran at 4 degrees C for 24 hours. Posttransplant graft function was assessed throughout a 7-hour observation period. In the control group, 2 recipients died of right-sided heart failure caused by severe ischemia-reperfusion injury. All animals of the glycine groups survived the entire observation period. Pulmonary vascular resistance remained significantly (P < .01) lower in both glycine groups when compared with controls. At the end of the observation period pulmonary vascular resistance in the control group was higher (P < .01) compared with the glycine groups (1310 +/- 319 dyn x sec x cm(-5) vs 879 +/- 127 dyn x sec x cm(-5) [LPD-glyc] vs 663 +/- 191 dyn x sec x cm(-5) [IV-glyc]). Changes of lung tissue water content were lower in the IV-glyc group compared with the LPD-control (P < .01) and LPD-glyc lungs (P < .05). Oxygenation (PO2/FiO2) was higher in the IV-glyc group compared with the LPD-glyc and control lungs (445 +/- 110 mm Hg vs 388 +/- 124 mm Hg [P < .01] vs 341 +/- 224 mm Hg [P < .001], respectively). Modification of low-potassium dextran solution with glycine or donor preconditioning ameliorates ischemia-reperfusion injury in lung transplantation. This intriguing approach merits further evaluation with respect to the mechanisms involved and may improve results in clinical lung preservation.

Up-Regulation of Endothelial Nitric Oxide Synthase Inhibits Pulmonary Leukocyte Migration Following Lung Ischemia-Reperfusion in Mice

Endogenous nitric oxide (NO) is known to modulate post-ischemic inflammatory response in various organs. However, the role of nitric oxide synthase isoforms (NOS) in mediating pulmonary post-ischemic inflammatory response is poorly understood. We therefore studied post-ischemic endothelial adhesion molecule expression and leukocyte migration in endothelial NOS knockout (eNOS-KO) mice subjected to pulmonary ischemia and reperfusion in vivo. Under anesthesia and mechanical ventilation, the left pulmonary hilum in wild-type (WT) and eNOS-KO mice was clamped for 1 hour, followed by reperfusion for up to 24 hours. In WT mice, we observed a selective up-regulation of both eNOS mRNA and protein in lung tissue, while inducible NOS (iNOS) and neuronal NOS (nNOS) remained unchanged. Survival in eNOS-KO mice was reduced due to severe pulmonary edema, underlining an increased susceptibility to ischemia-reperfusion (I/R) injury. Interstitial tissue infiltration by CD18- and CD11a-positive white blood cells as well as lung tissue water content peaked at 5 hours of reperfusion and were found significantly higher than in WT mice. Enhanced leukocyte-endothelial interaction was associated with pronounced up-regulation of vascular cell adhesion molecule (VCAM) in eNOS-KO mice during post-ischemic reperfusion. We conclude that eNOS attenuates post-ischemic inflammatory injury to the lung most probably via inhibition of endothelial adhesion molecule expression.

In-situ topical cooling of lung grafts: early graft function and surfactant analysis in a porcine single lung transplant model.

Improvement of organ preservation is essential to facilitate acceptance of marginal donor lungs for transplantation. Thus, recruiting non-heart-beating donors (NHBD) may be one reasonable strategy to augment the organ-pool especially in the field of pulmonary transplantation. Topical cooling (TC) of donor lungs could provide fast organ-protection and is an available procedure even in smaller centers. In this study transplanted lung function and surfactant activity in same lungs, which were preserved by TC, were assessed following transplantation. Twelve porcine allogeneic single lung transplants were performed. Six lungs that were flush preserved through the antegrade route served as controls. The other six lungs were preserved by TC for 30 min after induction of cardiac arrest by repeated application of cold saline (8 degrees C) to both pleural cavities. Lungs of both groups were stored in LPD solution for 24 h at 8 degrees C. After transplantation, the recipient's right bronchus and right pulmonary artery were clamped. Major endpoints included early graft function over a period of 7 h. Hemodynamic measures and respiratory functions were recorded in 30-min intervals. Surfactant function was determined before transplantation and 2 h after reperfusion by broncho-alveolar lavage fluid analysis. Only four animals of the control-group survived the 7 h reperfusion period. Right heart failure occurred in two animals after 150 and 240 min of reperfusion. All six animals in the TC group survived the observation period. Pulmonary vascular resistance (p<0.01), pulmonary artery pressure (p=0.03), and lung tissue water content remained significantly lower in topically cooled allografts (p=0.01) vs. controls. Surfactant function after transplantation was comparable in both groups with a trend towards lower protein contents (p=0.07) in the broncho-alveolar fluid of grafts after TC. In-situ TC seems to be a reliable strategy to preserve lungs for up to 24 h. It even surpasses the results of LPD-perfused grafts in hemodynamic function and survival time.

Lung water and proton magnetic resonance relaxation in preterm and term rabbit pups: their relation to tissue hyaluronan.

The present study was performed to investigate simultaneously total lung water, T(1) and T(2) relaxation times, and hyaluronan (HA) in preterm and term rabbits. Attempts were also made to establish the relationship of HA to total lung water and to T(2)-derived motionally distinct water fractions. Experiments were performed in fetal Pannon white rabbit pups at gestational ages of 25, 27, 29, and 31 d and at a postnatal age of 4 d. Lung tissue water content (desiccation method), T(1) and T(2) relaxation times (H(1)-NMR method), and HA concentration (radioassay) were measured, and free and bound water fractions were calculated by using multicomponent fits of the T(2) relaxation curves. Lung water content and T(1) and T(2) relaxation times were highest at a gestational age of 27 d and then declined steadily during the whole study period. Similar trends and time courses were seen for the fast and slow components of the T(2) relaxation curve. The T(2)-derived free water fraction remained unchanged at a gestational age of 25-29 d ( approximately 67%), but increased progressively to a value of 78.5 +/- 7.9% at 31 d (p < 0. 001) and to 83.4 +/- 9.4% at the postnatal age of 4 d (p < 0.01). Opposite changes occurred in the bound water fraction. Lung HA concentration decreased with advancing gestation from 870.8 +/- 205.2 microg/g dry weight at 25 d to 162.6 +/- 32.4 microg/g dry weight at 31 d (p < 0.001), but it was increased 2-fold postnatally. HA correlated positively with total lung water (r = 0.39; p < 0.001) but not with the bound water fraction. It is suggested that the physiologic lung dehydration is associated with macromolecule-related reorganization of lung water and that the role of HA in this process needs to be further investigated.

Time domain reflectometry: measurement of free water in normal lung and pulmonary edema.

The free water content of lung tissue was investigated by dielectric spectroscopy in normal lungs and in pulmonary edema induced by oleic acid in rats. The dielectric relaxation in a frequency range of 10(7) to 10(10) Hz was measured with the time domain reflectometry method at 25 degreesC. Three dielectric relaxation processes were analyzed for the lung tissue. A high-frequency process around 10 GHz was attributed to the orientation of free water molecules based on the relaxation time [log tauh (in s) = -11.03]. The dielectric strength (Delta epsilon) of this high-frequency peak (Delta epsilonh) should reflect the amount of free water in the tissue. Because the measured Delta epsilonh depended on the air content of the lung samples, the value of Delta epsilonh was corrected for the air content of each sample as determined by the point-counting method in the area where the time domain reflectometry data were obtained. The lungs of rats that received an injection of oleic acid had a significantly increased free water content [(Delta epsilonh of lung/Delta epsilon of pure water) x density of pure water] compared with that in the normal lung (0.76 vs. 0.59 g/cm3). These results indicate that free water occupies approximately 60% of the total volume of normal lung tissue and that there is an increase in free water in pulmonary edema.

Effects of Differential Lung Ventilation with Positive End-Expiratory Pressure on Ischemia-Reperfusion Lung Injury in Dogs

Background : Ischemia-reperfusion injury and ventilation/perfusion mismatch are the major complication of lung transplantation. Application of positive end-expiratory pressure(PEEP) on reperfused lung can prevent hypoxemia, because it increases functional residual capacity and improves oxygenation without contralateral dynamic hyperexpansion. To identify which differential lung ventilation with PEEP reduces ischemia-reperfusion lung injury, PaO2, intrapulmonary shunt, pulmonary compliance and water content of lung tissue were measured and compared with those of conventional two lung ventilation. Methods : Nineteen Korean mongrel dogs were included for study. Double lumen endotracheal tube was inserted via tracheostomy site. Femoral arterial catheter and Swan-Ganz catheter were inserted for hemodynamic data and thoracotomy was done. The right pulmonary artery, vein, and main bronchus were clamped for 90 minutes and released to produce unilateral warm ischemia-reperfusion lung injury. In control group(C), conventional two lung ventilation was applied, and in experimental group(P), the right lung was ventilated with 10 cmH2O PEEP independent of the left lung. PaO2, intrapulmonary shunt, pulmonary compliance and water content of lung tissue were measured. Result : At 60 min after reperfusion, PaO2 in group P was higher than in group C(512.4±58.8 mmHg vs 263.6±165.8 mmHg), and intrapulmonary shunt was smaller(9.8±3.4 vs 25.9±11.3%). Dynamic and static pulmonary compliance in group P were higher than in group C(42.3±9.4, 95.2±14.7 vs 29.2±1.4, 60.2±17.1 dyne·sec/cm5). Water content of the right lung in group P was lower than in group C(81.1±1.6 vs 85.1±3.9%). Conclusion : In conclusion, these data suggest that application of positive end-expiratory pressure on reperfused lung is more effective to improve ventilation/perfusion mismatch and oxygenation, so it is thought to be a good treatment for ischemia-reperfusion lung injury. (Korean J Anesthesiol 1998; 35: 242∼251)

Measurement of total lung water from nuclear magnetic resonance images.

An accurate, non-invasive means of measuring pulmonary water is desirable, for both clinical and research use. Nuclear magnetic resonance imaging is theoretically very suitable for this purpose. Nuclear magnetic resonance (NMR) spectroscopy was used to show that the water content of lung tissue could be predicted accurately from the intensity of signal resulting from a 90 degree saturation recovery sequence. The water contained in an image section may, therefore, be calculated by reference to a 100% water standard. Lung water was obtained by imaging the lung in continuous sections and summing the water contents of the component sections. The method performed well when applied to a sponge phantom, but underestimated by up to 30% in excised sheep lung. The total (vascular and extravascular) pulmonary water measured by NMR in six healthy volunteers was 292 g (SD 58 g) or 4.6 g/kg body weight, less than predicted by some other indirect methods and post-mortem values. A briefer examination comprising two axial sections at standardised levels was also devised. In 15 healthy volunteers the mean water content of a 1.6 cm-thick axial section through the right lung was 17.8 g at the sternal angle, and 23.3 g 5 cm caudally. In the left lung, the values were 16.4 g and 16.3 g, respectively.