Injection Of Oleic Acid Research Articles

Inflammatory responses to neutral fat and fatty acids in multiple organs in a rat model of fat embolism syndrome

Fat embolism syndrome (FES) is a common complication of long bone fractures. FES is rare but with significant morbidity and occasional fatalities. Studies of animal models of FES are numerous; however, few studies compare inflammatory reactions in multiple organs. The present study investigated the effect of neutral fat and fatty acids, which cause changes in multiple organs and induce FES. Using rats we evaluated the ratio of lung-to-body weight and conducted histological analyses and quantitative analysis of inflammatory cytokine mRNAs in the lungs following intravenous administration of neutral fat or fatty acids. Neutral fat increased the ratio of lung-to-body weight, and neutral fat formed emboli in lung capillaries. The levels of interleukin-1 beta (IL-1β), IL-6 and tumor necrosis factor-alpha (TNF-α) in the lungs increased after injection of neutral fat and oleic acid. Analysis of the histologic changes revealed that the highest numbers of fat droplets, occluding the capillaries of the lungs, kidney, heart, and brain formed 12h after the injection of neutral fat and fat droplets gradually diminished 48h later. Fat droplets were not detected in any organs after the injection of oleic acid. IL-1β and TNF-α levels in the lungs were elevated 9–24h after the injection of neutral fat, although IL-6 levels peaked at 6h. After injection of oleic acid, peak levels of IL-1β, IL-6, and TNF-α were detected at 6h, and IL-6 again increased in all organs and plasma at 15h. Neutral fat, but not fatty acids, formed emboli in the capillaries of multiple organs. These findings suggest that neutral fat increased inflammatory cytokine levels by forming emboli in organ capillaries, particularly in the lungs, while oleic acid augmented inflammatory cytokine levels by stimulating endothelial cells of multiple organs.

Effect of high frequency oscillatory ventilation on EVLW and lung capillary permeability of piglets with acute respiratory distress syndrome caused by pulmonary and extrapulmonary insults.

The effect of high frequency oscillatory ventilation (HFOV) at early stage on hemodynamic parameters, extravascular lung water (EVLW), lung capillary permeability, CC16 and sICAM-1 in piglets with pulmonary or extrapulmonary acute respiratory distress syndrome (ARDS) was explored. Central vein pressure (CVP) and pulse indicator continuous cardiac output (PiCCO) were monitored in 12 anesthetized and intubated healthy piglets. Pulmonary ARDS (ARDSp) and extrapulmonary ARDS (ARDSexp) models were respectively established by lung lavage of saline solution and intravenous injection of oleic acid. Then the piglets received HFOV for 4 h. EVLW index (EVLWI), EVLW/intratroracic blood volume (ITBV) and pulmonary vascular permeability index (PVPI) were measured before and after modeling (T0 and T1), and T2 (1 h), T3 (2 h), T4 (3 h) and T5 (4 h) after HFOV. CC16 and sICAM-1 were also detected at T1 and T5. Results showed at T1, T3, T4 and T5, EVLWI was increased more significantly in ARDSp group than in ARDSexp group (P<0.05). The EVLWI in ARDSp group was increased at T1 (P=0.008), and sustained continuously within 2 h (P=0.679, P=0.216), but decreased at T4 (P=0.007) and T5 (P=0.037). The EVLWI in ARDSexp group was also increased at T1 (P=0.003), but significantly decreased at T3 (P=0.002) and T4 (P=0.019). PVPI was increased after modeling in both two groups (P=0.004, P=0.012), but there was no significant change within 4 h (T5) under HFOV in ARDSp group, while PVPI showed the increasing trends at first, then decreased in ARDSexp group after HFOV. The changes of EVLW/ITBV were similar to those of PVPI. No significant differences were found in ΔEVLWI (P=0.13), ΔPVPI (P=0.28) and ΔEVLW/ITBV between the two groups (P=0.63). The significant decreases in both CC16 and sICAM-1 were found in both two groups 4 h after HFOV, but there was no significant difference between the two groups. It was concluded that EVLWI and lung capillary permeability were markedly increased in ARDSp and ARDSexp groups. EVLW could be decreased 4 h after the HFOV treatment. HFOV, EVLW/ITBV and PVPI were increased slightly at first, and then decreased in ARDSexp group, while in ARDSp group no significant difference was found after modeling. No significant differences were found in the decreases in EVLW and lung capillary permeability 4 h after HFOV.

Pharmacological characterization of [trans-5'-(4-amino-7,7-dimethyl-2-trifluoromethyl-7H-pyrimido[4,5-b][1,4]oxazin-6-yl)-2',3'-dihydrospiro(cyclohexane-1,1'-inden)-4-yl]acetic acid monobenzenesulfonate (JTT-553), a novel acyl CoA:diacylglycerol transferase (DGAT) 1 inhibitor.

Acyl CoA:diacylglycerol acyltransferase (DGAT) 1 is an enzyme that catalyzes the final step in triglyceride (TG) synthesis. This enzyme is considered to be a potential therapeutic target for obesity and diabetes. Here, results of an investigation of the pharmacological effects of JTT-553 [trans-5'-(4-amino-7,7-dimethyl-2-trifluoromethyl-7H-pyrimido[4,5-b][1,4]oxazin-6-yl)-2',3'-dihydrospiro(cyclohexane-1,1'-inden)-4-yl]acetic acid monobenzenesulfonate, a novel DGAT1 inhibitor, are reported. To measure the inhibitory activity of JTT-553 against DGAT1, TG synthesis using [(14)C]-labeled oleoyl-CoA was evaluated. Similarly, the inhibitory activity of JTT-553 against DGAT2, an isozyme of DGAT1, and acyl-CoA cholesterol acyltransferase (ACAT) 1, which is highly homologous to DGAT1, were evaluated. JTT-553 selectively inhibited human DGAT1 and showed comparable inhibitory effects on the activity of human, rat, and mouse DGAT. In vivo, JTT-553 suppressed plasma TG and chylomicron TG levels after olive oil loading in Sprague-Dawley (SD) rats. JTT-553 also inhibited TG synthesis in epididymal fat after [(14)C] oleic acid injection in C57BL/6J mice. Food intake was evaluated in SD rats fed 3.1%, 13%, or 35% (w/w) fat diets. In rats fed the 35% fat diet, JTT-553 reduced food intake. This reduction of food intake was observed 2 h after feeding, lasted for 24 h, and correlated with dietary fat content. Furthermore, JTT-553 reduced daily food intake and body weight gain in diet-induced obese rats after 4-week repeated administration. JTT-553 exerted multiple effects on intestinal fat absorption, adipose fat synthesis, and food intake, and consequently induced body weight reduction. Therefore, JTT-553 is expected to be an effective novel therapeutic agent for the treatment of obesity.

Human peripheral blood CD34+ cells attenuate oleic acid–induced acute lung injury in rats

Background aimsAdult stem cell–based therapy is a promising novel approach for treatment of acute lung injury (ALI). In this study, we evaluated the therapeutic effect of isolated human peripheral blood CD34+ progenitor cells in an ALI rat model, induced by oleic acid (OA) injection. MethodsSeventy-five adult female rats were used in this study. Group A, control without treatment, and group B, control injected with phosphate-buffered saline, comprised 15 rats each; the remaining 45 rats were injected with OA to induce ALI and were further subdivided into 3 groups: group C (ALI group, 15 rats), group D (ALI and fibroblast group, 15 rats) and group E (ALI and CD34+ cell group, 15 rats). ResultsCD34+ cells transplantation in rats with OA-induced lung injury improves the arterial PaO2 and wet/dry ratio, reduces infiltration of inflammatory cells and decreases lung vascular permeability as determined by reduced intra-alveolar and interstitial patchy congestion and hemorrhage as well as decreased interstitial edema. Additionally, lung inflammation determined by expression of the pro-inflammatory mediators intercellular adhesion molecule 1 and tumor necrosis factor-α was attenuated in CD34+ cell–treated rats at 6, 24 and 48 h post-OA challenge compared with non-treated rats. Moreover, the expression of anti-inflammatory molecule interleukin-10 was up-regulated in the lung of OA-induced ALI rats after administration of CD34+ cells. The important finding was that human TNF-α-induced protein 6 (TSG-6) gene expression was significantly up-regulated in rats treated with CD34+ cells. ConclusionsThe freshly isolated human peripheral blood–derived CD34+ cells may be used as an important source of stem cells that improve ALI. The anti-inflammatory properties of CD34+ cells in the lung are explained, at least in part, by activation of CD34+ cells to express TSG-6.

Identification and examination of a novel 9-bp insert/deletion polymorphism on porcine SFTPA1 exon 2 associated with acute lung injury using an oleic acid-acute lung injury model.

The pulmonary surfactant-associated protein (SFTPA1, SP-A) gene has been studied as a candidate gene for lung disease resistance in humans and livestock. The objective of the present study was to identify polymorphisms of the porcine SFTPA1 gene coding region and its association with acute lung injury (ALI). Through DNA sequencing and the PCR-single-strand conformation polymorphism method, a novel 9-bp nucleotide insertion (+) or deletion (-) was detected on exon 2 of SFTPA1, which causes a change in three amino acids, namely, alanine (Ala), glycine (Gly) and proline (Pro). Individuals of three genotypes (-/-, +/- and +/+) were divided into equal groups from 60 Rongchang pigs that were genotyped. These pigs were selected for participation in the oleic acid (OA)-ALI model by 1-h and 3-h injections of OA, and there were equal numbers of pigs in the control and injection groups. The lung water content, a marker for acute lung injury, was measured in this study; there is a significant correlation between high lung water content and the presence of the 9-bp indel polymorphism (P < 0.01). The lung water content of the OA injection group was markedly higher than that of the control group and lung water content for the +/+ genotype was significantly higher than that of the others in the 1-h group (P < 0.01). No differences in the expression of the SFTPA1 gene were found among individuals with different SFTPA1 genotypes, indicating that the trait is not caused by a linked polymorphism causing altered expression of the gene. The individuals with the -/- genotype showed lower lung water content than the +/+ genotype pigs, which suggests that polymorphism could be a potential marker for lung disease-resistant pig breeding and that pig can be a potential animal model for human lung disease resistance in future studies.

Characterization of a double-hit murine model of acute respiratory distress syndrome.

The aim of the present study was to characterize a murine model of acute respiratory distress syndrome (ARDS) abiding by the Berlin definition of human ARDS and guidelines for animal models of ARDS. To this end, C57BL/6NCrl mice were challenged with lipopolysaccharide (LPS; 15 mg/kg, i.p.) followed 18 h later by injection of oleic acid (OA; 0.12 mL/kg, i.v.). Controls received saline injection at both time points. Haemodynamics were monitored continuously. Arterial blood gas analyses were performed just before and every 30 min after OA challenge. Ninety minutes after OA challenge, the chest of mice was scanned using micro-computed tomography (CT). Cytokine concentrations were measured in plasma samples. Lungs were harvested 90 min after OA challenge for histology, immunohistochemistry, lung weight measurements and tissue cytokine detection. A histological lung injury score was determined. Eighteen hours after LPS challenge, mice exhibited a severe systemic inflammatory response syndrome. Oxygenation declined significantly after OA injections (Pa o2 /Fi o2 283 ± 73 and 256 ± 71 mmHg at 60 and 90 min, respectively; P < 0.001). Bilateral patchy infiltrates were present on the micro-CT scans. Histology revealed parenchymal damage with accumulation of polymorphonuclear neutrophils, intra-alveolar proteinacous debris and few hyaline membranes. The lung wet : dry ratio indicated damage to the alveolar capillary membrane. Cytokine patterns evidenced a severe local and systemic inflammatory state in plasma and lung tissue. In conclusion, the described two-hit model of ARDS shows a pathological picture of ARDS closely mimicking human ARDS according to the Berlin definition and may facilitate interpretation of prospective experimental results.

Flow-controlled expiration: a novel ventilation mode to attenuate experimental porcine lung injury

Whereas the effects of various inspiratory ventilatory modifications in lung injury have extensively been studied, those of expiratory ventilatory modifications are less well known. We hypothesized that the newly developed flow-controlled expiration (FLEX) mode provides a means of attenuating experimental lung injury. Experimental acute respiratory distress syndrome was induced by i.v. injection of oleic acid in 15 anaesthetized and mechanically ventilated pigs. After established lung injury ([Formula: see text]ratio <27 kPa), animals were randomized to either a control group receiving volume-controlled ventilation (VCV) or a treatment group receiving VCV with additional FLEX (VCV+FLEX). At predefined times, lung mechanics and oxygenation were assessed. At the end of the experiment, the pigs were killed, and bronchoalveolar fluid and lung biopsies were taken. Expression of inflammatory cytokines was analysed in lung tissue and bronchoalveolar fluid. Lung injury score was determined on the basis of stained tissue samples. Compared with the control group (VCV; n=8), the VCV+FLEX group (n=7) demonstrated greater dynamic lung compliance and required less PEEP at comparable [Formula: see text] (both P<0.05), had lower regional lung wet-to-dry ratios and lung injury scores (both P<0.001), and showed less thickening of alveolar walls (an indicator of interstitial oedema) and de novo migration of macrophages into lung tissue (both P<0.001). The newly developed FLEX mode is able to attenuate experimental lung injury. FLEX could provide a novel means of lung-protective ventilation.

Effect of transplantation of endothelial progenitor cells on inflammatory responses during oleic acid-induced acute lung injury in rabbits

Objective To evaluate the effects of transplantation of endothelial progenitor cells (EPCs) on inflanmatory responses during acute lung injury (ALI) induced by oleic acid in rabbits.Methods Ninety-six New Zealand male rabbits,aged 7-10 months,weighing 2.5-3.0 kg,were randomly divided into 4 groups using a random number table:control group (group C,n =16),transplantation of EPC group (group EPC,n =32),ALI group and ALI + transplantation of EPC group (group ALI + EPC,n =32).ALI was induced by iv 20％ emulsified oleic acid 75 mg/kg.EPCs (106 cells,in 1 ml of PBS) or the equal volume of PBS was administered intravenously at 0.5 h after iv oleic acid injection.Eight animals were randomly chosen at 6,12,24 and 48 h after oleic acid injection (T1-4) in LI and ALI+ EPC groups,or at T3,4 in C and EPC groups,and then sacrificed.The lungs were removed for determination of the expression of NF-κB mRNA (by RT-PCR),TNF-α,IL-1β and activity of NF-κB (by Western blot),and for microscopic examination of pathological changes of lung tissues (using HE staining).Diffuse alveolar damage (DAD) score was carried out.Results Compared with group C,the expression of NF-κB mRNA,IL-1β and TNF-α was significantly up-regulated,and NF-κB activity and DAD score were increased at T3,4 in ALI and ALI + EPC groups,and no significant change was found in the parameters mentioned above in EPC group.Compared with ALI group,the expression of NF-κB mRNA,TNF-α and IL-1β was significantly down-regulated,and NF-κB activity and DAD score were decreased at T1-4 in ALI + EPC group.Conclusion The mechanism by which EPCs mitigate ALI induced by oleic acid is related to inhibition of inflammatory responses in rabbits. Key words: Endothelial cells; Stem cell transplantation ; Respiratory distress syndrome, adult; Oleic acid; Inflammation

Extracorporeal Gas Exchange and Spontaneous Breathing for the Treatment of Acute Respiratory Distress Syndrome

Venovenous extracorporeal gas exchange is increasingly used in awake, spontaneously breathing patients as a bridge to lung transplantation. Limited data are available on a similar use of extracorporeal gas exchange in patients with acute respiratory distress syndrome. The aim of this study was to investigate the use of extracorporeal gas exchange in awake, spontaneously breathing sheep with healthy lungs and with acute respiratory distress syndrome and describe the interactions between the native lung (healthy and diseased) and the artificial lung (extracorporeal gas exchange) in this setting. Laboratory investigation. Animal ICU of a governmental laboratory. Eleven awake, spontaneously breathing sheep on extracorporeal gas exchange. Sheep were studied before (healthy lungs) and after the induction of acute respiratory distress syndrome via IV injection of oleic acid. Six gas flow settings (1-10 L/min), resulting in different amounts of extracorporeal CO2 removal (20-100% of total CO2 production), were tested in each animal before and after the injury. Respiratory variables and gas exchange were measured for every gas flow setting. Both healthy and injured sheep reduced minute ventilation according to the amount of extracorporeal CO2 removal, up to complete apnea. However, compared with healthy sheep, sheep with acute respiratory distress syndrome presented significantly increased esophageal pressure variations (25 ± 9 vs 6 ± 3 cm H2O; p < 0.001), which could be reduced only with very high amounts of CO2 removal (> 80% of total CO2 production). Spontaneous ventilation of both healthy sheep and sheep with acute respiratory distress syndrome can be controlled via extracorporeal gas exchange. If this holds true in humans, extracorporeal gas exchange could be used in awake, spontaneously breathing patients with acute respiratory distress syndrome to support gas exchange. A deeper understanding of the pathophysiology of spontaneous breathing during acute respiratory distress syndrome is however warranted in order to be able to propose extracorporeal gas exchange as a safe and valuable alternative to mechanical ventilation for the treatment of patients with acute respiratory distress syndrome.

Effect of positive end‐expiratory pressure on acoustic wave propagation in experimental porcine lung injury

To evaluate the effect of positive end-expiratory pressure (PEEP) on sound propagation through injured lungs, we injected a multifrequency broad-band sound signal into the airway of eight anesthetized, intubated and mechanically ventilated pigs, while recording transmitted sound at three locations bilaterally on the chest wall. Oleic acid injections effected a severe pulmonary oedema predominately in the dependent lung regions, with an average increase in venous admixture from 19 ± 15 to 59 ± 14% (P < 0.001), and a reduction in dynamic respiratory system compliance from 34 ± 7 to 14 ± 4 ml cmH2 O(-1) (P < 0.001). A concomitant decrease in sound transit time was seen in the dependent lung regions (P < 0.05); no statistically significant change occurred in the lateral or non-dependent areas. The application of PEEP resulted in a decrease in venous admixture, increase in respiratory system compliance and return of the sound transit time to pre-injury levels in the dependent lung regions. Our results indicate that sound transmission velocity increases in lung tissue affected by permeability-type pulmonary oedema in a manner reversible during alveolar recruitment with PEEP.

Effects of recruitment maneuvers with PEEP on lung volume distribution in canine models of direct and indirect lung injury

Lung recruitment maneuvers can help open collapsed lung units for sufficient oxygenation, and positive end expiratory pressure (PEEP) is used to keep the lung open after recruitment. However, the application of high PEEP levels may play a significant role in causing regional lung hyperinflation during mechanical ventilation. The authors sought to study the effects of PEEP targeting optimal oxygenation on regional lung volume distribution in a direct and an indirect acute respiratory distress syndrome (ARDS) model. ARDS was induced by either surfactant depletion or oleic acid injection in dogs. After lung recruitment, PEEP was decreased from 20 to 10cmH2O in 2cmH2O steps every 10min to examine regional lung aeration by using computed tomography. Lung injury appeared to be localized in the model of surfactant depletion while it widely diffused after oleic acid infusion. At PEEP levels that achieved optimal oxygenation, nonaerated lung units decreased and normally aerated lung units enhanced, but hyperinflated areas increased significantly in both models (P<0.05). Hyperinflated areas were greater in the surfactant depletion model than in the oleic acid model at PEEP levels applied (P<0.05). Optimal oxygenation guided PEEP may cause hyperinflated in both focal lung injury and diffused lung injury post lung recruitment. Hyperinflation was more susceptible in focal lung injury than in diffused lung injury post lung recruitment.

Changes in breath sound power spectra during experimental oleic acid-induced lung injury in pigs

To evaluate the effect of acute lung injury on the frequency spectra of breath sounds, we made serial acoustic recordings from nondependent, midlung and dependent regions of both lungs in ten 35- to 45-kg anesthetized, intubated, and mechanically ventilated pigs during development of acute lung injury induced with intravenous oleic acid in prone or supine position. Oleic acid injections rapidly produced severe derangements in the gas exchange and mechanical properties of the lung, with an average increase in venous admixture from 16 ± 12 to 62 ± 16% (P < 0.01), and a reduction in dynamic respiratory system compliance from 25 ± 4 to 14 ± 4 ml/cmH2O (P < 0.01). A concomitant increase in sound power was seen in all lung regions (P < 0.05), predominantly in frequencies 150-800 Hz. The deterioration in gas exchange and lung mechanics correlated best with concurrent spectral changes in the nondependent lung regions. Acute lung injury increases the power of breath sounds likely secondary to redistribution of ventilation from collapsed to aerated parts of the lung and improved sound transmission in dependent, consolidated areas.

TIP peptide inhalation in oleic acid-induced experimental lung injury: a post-hoc comparison

BackgroundThe lectin-like domain of TNF-α mimicked by an inhaled TIP peptide represents a novel approach to attenuate a pulmonary edema in respiratory failure, which is on the threshold to clinical application. In extension to a previously published study, which reported an improved pulmonary function following TIP peptide inhalation in a porcine model of lavage-induced lung injury, a post-hoc comparison to additional experiments was conducted. This analysis addresses the hypothesis that oleic acid injection-induced capillary leakage and alveolar necrosis blunts the previously reported beneficial effects of TIP peptide inhalation in a porcine model.FindingsFollowing animal care committee approval lung injury was induced by oleic acid injection in six pigs with a setting strictly according to a previously published protocol that was used for lung-lavaged pigs. Ventilation/perfusion-distribution by multiple inert gas elimination, parameters of gas exchange and pulmonary edema were assessed as surrogates of the pulmonary function. A significantly improved ventilation/perfusion-distribution following TIP inhalation was recognized only in the bronchoalveolar lavage model but not following oleic acid injection. The time course after oleic acid injection yielded no comparable impact of the TIP peptide on gas exchange and edema formation.ConclusionsReported beneficial effects of the TIP peptide on gas exchange and pulmonary edema were not reproducible in the oleic acid injection model. This analysis assumes that sustained alveolar epithelial necrosis as induced by oleic acid injection may inhibit the TIP-induced edema resolution. Regarding the on-going clinical development of the TIP peptide this approach should hardly be effective in states of severe alveolar epithelial damage.

Effect of oleic acid-induced acute lung injury and conventional mechanical ventilation on renal function in piglets.

Animal models that demonstrate changes of renal function in response to acute lung injury (ALI) and mechanical ventilation (MV) are few. The present study was performed to examine the effect of ALI induced by oleic acid (OA) in combination with conventional MV strategy on renal function in piglets. Twelve Chinese mini-piglets were randomly divided into two groups: the OA group (n = 6), animals were ventilated with a conventional MV strategy of 12 ml/kg and suffered an ALI induced by administration of OA, and the control group (n = 6), animals were ventilated with a protective MV strategy of 6 ml/kg and received the same amount of sterile saline. Six hours after OA injection a severe lung injury and a mild-moderate degree of renal histopathological injury were seen, while no apparent histological abnormalities were observed in the control group. Although we observed an increase in the plasma concentrations of creatinine and urea after ALI, there was no significant difference compared with the control group. Plasma concentrations of neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C increased (5.6 ± 1.3) and (7.4 ± 1.5) times in the OA group compared to baseline values, and were significantly higher than the values in the control group. OA injection in combination with conventional MV strategy resulted in a dramatic aggravation of hemodynamic and blood gas exchange parameters, while these parameters remained stable during the experiment in the control group. The plasma expression of TNF-α and IL-6 in the OA group were significantly higher than that in the control group. Compared with high expression in the lung and renal tissue in the OA group, TNF-α and IL-6 were too low to be detected in the lung and renal tissue in the control group. OA injection in combination with conventional MV strategy not only resulted in a severe lung injury but also an apparent renal injury. The potential mechanisms involved a cytokine response of TNF-α and IL-6 in plasma, lung and renal tissues.

The influence of pre-B-cell colony enhancing factor on adhesive molecule in pulmonary cells in rats with acute lung injury/acute respiratory distress syndrome

To observe the influence of pre-B-cell colony enhancing factor (PBEF) on intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in lung tissue of rats with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) induced by oleic acid. A total of 40 male adult Sprague-Dawley (SD) rats were divided into control, model, drug intervention and vehicle control groups according to the random digits table with 10 rats in each group. ALI/ARDS was reproduced in the rats of model, drug intervention and vehicle control groups by injection of oleic acid (0.15 ml/kg) through the tail vein. The rats in drug intervention and vehicle control groups received the specific PBEF inhibitor FK866 (10 mg/kg), while vehicle control group received the same volume of the vehicle only. Six hours after ALI/ARDS was successfully reproduced, bronchoalveolar alveolar lavage fluid (BALF) was obtained for the measurement of the contents of tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) by enzyme linked immunosorbent assay (ELISA). Lung tissue was obtained for pathological examination, and also for the measurement of the expression of PBEF, ICAM-1 and VCAM-1 mRNA by reverse transcription-polymerase chain reaction (RT-PCR), and also the protein levels of PBEF, ICAM-1 and VCAM-1 by immunohistochemistry. Compared with rats in control group, the lung tissue of rats in model group showed distinctive pathological changes, the contents of TNF-α and IL-1β in BALF were increased (TNF-α: 656.51±47.13 ng/L vs. 84.82±7.84 ng/L, IL-1β: 379.60±31.55 ng/L vs. 74.56±8.51 ng/L, both P<0.01), the mRNA and protein expression of PBEF, ICAM-1 and VCAM-1 were significantly increased (PBEF mRNA: 0.581±0.079 vs. 0.186±0.051, ICAM-1 mRNA: 0.558±0.060 vs. 0.176±0.070, VCAM-1 mRNA: 0.646±0.059 vs. 0.226±0.047; PBEF protein: 0.089±0.024 vs. 0.037±0.011, ICAM-1 protein: 0.061±0.012 vs. 0.025±0.008, VCAM-1 protein: 0.072±0.013 vs. 0.033±0.010, all P<0.01). Compared with model group, amelioration of pathological change was found in lung tissue of rats in drug intervention group, the contents of TNF-α and IL-1β in BALF were reduced (TNF-α: 478.80±72.93 ng/L vs. 656.51±47.13 ng/L, IL-1β: 244.62±52.17 ng/L vs. 379.60±31.55 ng/L, both P<0.05), and the mRNA and protein expression of PBEF, ICAM-1 and VCAM-1 were lowered (PBEF mRNA: 0.456±0.110 vs. 0.581±0.079, ICAM-1 mRNA: 0.413±0.073 vs. 0.558±0.060, VCAM-1 mRNA: 0.483±0.062 vs. 0.646±0.059; PBEF protein: 0.059±0.010 vs. 0.089±0.024, ICAM-1 protein: 0.043±0.007 vs. 0.061±0.012, VCAM-1 protein: 0.050±0.009 vs. 0.072±0.013, all P<0.05). PBEF could aggravate migration of pro-inflammatory cells to infiltrate the lung tissue by increasing the expression of ICAM-1 and VCAM-1, thus it plays an important role in the development of ALI/ARDS.

Hydrogen sulfide donor regulates alveolar epithelial cell apoptosis in rats with acute lung injury

Background Acute lung injury (ALI) is a common syndrome associated with high morbidity and mortality in emergency medicine. Cell apoptosis plays a key role in the pathogenesis of ALI. Hydrogen sulfide (H2S) plays a protective role during acute lung injury. We designed this study to examine the role of H2S in the lung alveolar epithelial cell apoptosis in rats with ALI. Methods Sixty-nine male Sprague Dawley rats were used. ALI was induced by intra-tail vein injection of oleic acid (OA). NaHS solution was injected intraperitonally 30 minutes before OA injection as the NaHS pretreatment group. Single sodium hydrosulfide pretreatment group and control group were designed. Index of quantitative assessment (IQA), wet/dry weight (W/D) ratio and the percentage of polymorphonuclear leukocyte (PMN) cells in the bronchoalveolar lavage fluid (BALF) were determined. H2S level in lung tissue was measured by a sensitive sulphur electrode. Apoptosis was evaluated by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining and Fas protein was measured by immunohistochemical staining. Results The level of endogenous H2S in lung tissue decreased with the development of ALI induced by OA injection. Apoptosis and Fas protein in alveolar epithelial cells increased in the ALI of rats but NaHS lessened apoptosis and Fas protein expression in alveolar epithelial cells of rats with ALI. Conclusion Endogenous H2S protects rats from oleic acid-induced ALI, probably by inhibiting cell apoptosis.

Low-dose CT for quantitative analysis in acute respiratory distress syndrome

IntroductionThe clinical use of serial quantitative computed tomography (CT) to characterize lung disease and guide the optimization of mechanical ventilation in patients with acute respiratory distress syndrome (ARDS) is limited by the risk of cumulative radiation exposure and by the difficulties and risks related to transferring patients to the CT room. We evaluated the effects of tube current-time product (mAs) variations on quantitative results in healthy lungs and in experimental ARDS in order to support the use of low-dose CT for quantitative analysis.MethodsIn 14 sheep chest CT was performed at baseline and after the induction of ARDS via intravenous oleic acid injection. For each CT session, two consecutive scans were obtained applying two different mAs: 60 mAs was paired with 140, 15 or 7.5 mAs. All other CT parameters were kept unaltered (tube voltage 120 kVp, collimation 32 × 0.5 mm, pitch 0.85, matrix 512 × 512, pixel size 0.625 × 0.625 mm). Quantitative results obtained at different mAs were compared via Bland-Altman analysis.ResultsGood agreement was observed between 60 mAs and 140 mAs and between 60 mAs and 15 mAs (all biases less than 1%). A further reduction of mAs to 7.5 mAs caused an increase in the bias of poorly aerated and nonaerated tissue (-2.9% and 2.4%, respectively) and determined a significant widening of the limits of agreement for the same compartments (-10.5% to 4.8% for poorly aerated tissue and -5.9% to 10.8% for nonaerated tissue). Estimated mean effective dose at 140, 60, 15 and 7.5 mAs corresponded to 17.8, 7.4, 2.0 and 0.9 mSv, respectively. Image noise of scans performed at 140, 60, 15 and 7.5 mAs corresponded to 10, 16, 38 and 74 Hounsfield units, respectively.ConclusionsA reduction of effective dose up to 70% has been achieved with minimal effects on lung quantitative results. Low-dose computed tomography provides accurate quantitative results and could be used to characterize lung compartment distribution and possibly monitor time-course of ARDS with a lower risk of exposure to ionizing radiation. A further radiation dose reduction is associated with lower accuracy in quantitative results.

Molecular-biological analysis of acute lung injury (ALI) induced by heat exposure and/or intravenous administration of oleic acid

The aim of this study was to molecular-biologically investigate the interaction between heat exposure and pulmonary fat embolization in regards to the development of acute lung injury (ALI). Ten-week-old Wistar male rats were divided into four groups: (1) oleic acid injected into caudal vein after heat exposure, (2) oleic acid injected without heat exposure, (3) soybean oil injected after heat exposure, and (4) soybean oil injected without heat exposure, and then mRNA expression of eight inflammatory mediators related to ALI/acute respiratory distress syndrome (ARDS) and heat shock protein 70 (Hsp70) in lung was determined 1h after the injection. mRNA expression of interleukin 1 beta (Il1b), tumor necrosis factor alpha (Tnfa), vascular endothelial growth factor A (Vegfa), transforming growth factor beta 1 (Tgfb1) and Hsp70 was significantly increased by heat exposure, while that of Il1b, interleukin 6 (Il6), Tnfa, macrophage inflammatory protein 2 (Mip2) and granulocyte macrophage-colony stimulating factor (Gm-csf) was significantly elevated by the injection of oleic acid. Moreover, the expressions of inflammatory cytokines and chemokines in lung almost paralleled their mRNA expressions. In particular, IL-1β expression was synergistically elevated by heat exposure followed by injection of oleic acid. Additionally, IL-6 expression tended to increase under the same conditions as well. It is likely that heat exposure itself injures lung tissue within a short time, and that more than two conditions which induce ALI/ARDS interact with each other synergistically, exacerbating the development of ALI/ARDS.

Effect of different fluid therapy on oxgen metabolism and gastric mucosal pH of acute respiratory distress syndrome piglets caused by pulmonary and extrapulmonary insults

Objective To observe the heterogeneous response of oxgen metabolism and gastric mucosal pH of acute respiratory distress syndrome (ARDS) piglets caused by pulmonary and extrapulmonary insults to restrictive or non-restrictive fluid therapy.Methods 24 piglets were randomly divided into ARDSp (caused by hydrochloric acid lung lavage) group (group A) and ARDSexp (caused by oleic acid injection) group (group B).In group A or B,piglets were randomly treated by restrictive ( group A1,B1 ) or non-restrictive (group B1,B2) fluid therapy for 6h guided by EGDT.The results of oxygenation index and pH1 were measured on different time points.Results After ARDSp/ARDSexp models were established,arterial oxygenation index reduced to below 200,and pH1 got worsen obviously ( ＜ 7.32 ).Afer the 6h fluid therapy,arterial oxygenation index exhibited improvement in Group B1,All piglets exhibited improvement of pH1 but the effects were less significant in Group B1.Conclusion Restrictive fluid therapy can help to improve oxygenation and reduce pulmonary edema in ARDSexp,but may result in organ hypoperfusion. Key words: Restrictive fluid therapy; ARDSp/ARDSexp; Oxgen metabolism; Gastric mucosal pH

Tidal recruitment assessed by electrical impedance tomography and computed tomography in a porcine model of lung injury*

To determine the validity of electrical impedance tomography to detect and quantify the amount of tidal recruitment caused by different positive end-expiratory pressure levels in a porcine acute lung injury model. Randomized, controlled, prospective experimental study. Academic research laboratory. Twelve anesthetized and mechanically ventilated pigs. Acute lung injury was induced by central venous oleic acid injection and abdominal hypertension in seven animals. Five healthy pigs served as control group. Animals were ventilated with positive end-expiratory pressure of 0, 5, 10, 15, 20, and 25 cm H2O, respectively, in a randomized order. At any positive end-expiratory pressure level, electrical impedance tomography was obtained during a slow inflation of 12 mL/kg of body weight. Regional-ventilation-delay indices quantifying the time until a lung region reaches a certain amount of impedance change were calculated for lung quadrants and for every single electrical impedance tomography pixel, respectively. Pixel-wise calculated regional-ventilation-delay indices were plotted in a color-coded regional-ventilation-delay map. Regional-ventilation-delay inhomogeneity that quantifies heterogeneity of ventilation time courses was evaluated by calculating the scatter of all pixel-wise calculated regional-ventilation-delay indices. End-expiratory and end-inspiratory computed tomography scans were performed at each positive end-expiratory pressure level to quantify tidal recruitment of the lung. Tidal recruitment showed a moderate inter-individual (r = .54; p < .05) and intra-individual linear correlation (r = .46 up to r = .73 and p < .05, respectively) with regional-ventilation-delay obtained from lung quadrants. Regional-ventilation-delay inhomogeneity was excellently correlated with tidal recruitment intra- (r = .90 up to r = .99 and p < .05, respectively) and inter-individually (r = .90; p < .001). Regional-ventilation-delay can be noninvasively measured by electrical impedance tomography during a slow inflation of 12 mL/kg of body weight and visualized using ventilation delay maps. Our experimental data suggest that the impedance tomography-based analysis of regional-ventilation-delay inhomogeneity provides a good estimate of the amount of tidal recruitment and may be useful to individualize ventilatory settings.