Injection Of Oleic Acid Research Articles

Gossypin mitigates oxidative damage by downregulating the molecular signaling pathway in oleic acid-induced acute lung injury.

One of the leading causes of acute lung injury, which is linked to a high death rate, is pulmonary fat embolism. Increases in proinflammatory cytokines and the production of free radicals are related to the pathophysiology of acute lung injury. Antioxidants that scavenge free radicals play a protective role against acute lung injury. Gossypin has been proven to have antioxidant, antimicrobial, and anti-inflammatory properties. In this study, we compared the role of Gossypin with the therapeutically used drug Dexamethasone in the acute lung injury model caused by oleic acid in rats. Thirty rats were divided into five groups; Sham, Oleic acid model, Oleic acid+Dexamethasone (0.1 mg/kg), Oleic acid+Gossypin (10 and 20 mg/kg). Two hours after pretreatment with Dexamethasone or Gossypin, the acute lung injury model was created by injecting 1 g/kg oleic acid into the femoral vein. Three hours following the oleic acid injection, rats were decapitated. Lung tissues were extracted for histological, immunohistochemical, biochemical, PCR, and SEM imaging assessment. The oleic acid injection caused an increase in lipid peroxidation and catalase activity, pathological changes in lung tissue, decreased superoxide dismutase activity, and glutathione level, and increased TNF-α, IL-1β, IL-6, and IL-8 expression. However, these changes were attenuated after treatment with Gossypin and Dexamethasone. By reducing the expression of proinflammatory cytokines and attenuating oxidative stress, Gossypin pretreatment provides a new target that is equally effective as dexamethasone in the treatment of oleic acid-induced acute lung injury.

Therapeutic effects of minocycline on oleic acid-induced acute respiratory distress syndrome (ARDS) in rats.

Acute respiratory distress syndrome (ARDS) is a serious intensive care condition. Despite advances in treatment over the previous few decades, ARDS patients still have high fatality rates. Thus, more research is needed to improve the outcomes for people with ARDS. Minocycline is an antibiotic with antioxidant, anti-inflammatory, and anti-apoptotic effects. In the current investigation, the therapeutic effects of minocycline on oleic acid-induced ARDS were evaluated. Male rats were classified into 6 groups, 1. control (normal saline), 2. oleic acid (100 µL, i.v.), 3-5. oleic acid + minocycline (50, 100, 200mg/kg, i.p.), and 6. minocycline (200mg/kg, i.p.) alone. Twenty-four hours after the oleic acid injection, the lung tissue is isolated, weighed, and the middle part of the right lung is immediately placed in the freezer, while the middle part of the left lung is placed in formalin and sent to the laboratory for pathology testing. Then, the amounts of malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), cytokines (interleukin-1 beta (IL-1β), tumor necrosis factor-α (TNF-α)), B-cell lymphoma 2 (Bcl-2), Bcl-2 associated X (Bax), and cleaved caspase-3 were determined in lung tissue. Administration of oleic acid increased emphysema, inflammation, vascular congestion, hemorrhage, MDA amount, Bax/Bcl-2 ratio, cleaved caspase-3, IL-1β, TNF-α levels, and decreased GSH, SOD, and CAT levels in comparison with the control group. The administration of minocycline could significantly reduce pathological and biochemical alterations induced by oleic acid. Minocycline has a therapeutic effect on oleic acid-induced ARDS through antioxidant, anti-inflammatory, and anti-apoptotic properties.

Angiopoietin-Like Protein 2 Is Increased in Obese Mouse Models of Lung Injury.

Objective To investigate the regulatory role of angiopoietin-1ike protein 2 (Angptl 2) in the pathogenesis of acute respiratory distress syndrome (ARDS). Methods A high-fat diet (HFD) and tail vein injection of 0.1 ml/kg oleic acid were used to induce acute lung injury (ALI) and ARDS models, and male Kunming mice were randomly divided into four groups: control group (injected with normal saline), ALI group (injected with oleic acid), HFD group (injection of normal saline), and ARDS group (HFD+injection of oleic acid). The degree of lung injury was assessed by lung histopathology score and lung injury index. At the same time, the mRNA and protein expression levels of Angptl 2 in lung tissue were also detected to determine the relationship between Angptl 2 and ARDS. Results Lee's index of the HFD group and ARDS group was significantly higher than that of the control group and ALI group (P < 0.05), and the lung injury index of the ARDS group was significantly higher than that of the ALI group. The expression of Angptl 2 in the lung tissue of the ALI group and ARDS group was significantly different, and the Angptl 2 mRNA level was the highest in the ARDS group. Immunohistochemistry showed that the alveolar walls of the ALI group and ARDS group were severely collapsed, and the ARDS group had the greatest Angptl 2 aggregation at the site of edema exudation. Conclusion Collectively, obesity might be mediated by Angptl 2 and promotes lung injury. Immunohistochemistry analysis showed that the expression of the receptor on alveolar walls was correlated with Angptl 2, which increased alveolar wall permeability, edema fluid exudation, and alveolar wall collapse. Thus, Angptl 2 might be a target for improving the treatment of ARDS.

Biphasic positive airway pressure spontaneous breathing attenuates lung injury in an animal model of severe acute respiratory distress syndrome

ObjectiveTo compare the effects of unassisted spontaneous breathing (SB) and complete muscle paralysis (PC) on early severe acute respiratory distress syndrome (ARDS) in an animal model, and to explore the possibility of biphasic positive airway pressure (BIPAP) as lung protective ventilation support for patients in the early stage of severe ARDS.MethodsTwelve healthy beagle dogs between the ages of 10 and 15 months were randomly divided into two groups: the SB group (BIPAPSB) and the PC group (BIPAPPC). Arterial blood samples were drawn before modelling. Arterial blood gas analysis and mechanical tests were conducted. The animal model of severe ARDS was established using a deep intravenous injection of oleic acid, and BIPAP ventilation was performed for 8 hours. Lung tissue and blood were taken to detect lung function, inflammatory reactions and degree of pathological damage.ResultsAt the beginning of the experiment, there was no significant difference in the arterial blood gas analysis between the two groups (p > 0.05). After successful modelling, the oxygenation index and the end-expiratory lung volume in the SB group were significantly higher than those in the PC group 8 hours after MV. Pathologically, the wet-dry ratio and pathological score of the PC group were higher than those of the SB group; the lung injury in the gravity-dependent area in the SB group was less than that in the PC group (p< 0.05).ConclusionsIn the early stage of severe ARDS induced by oleic acid, compared with PC, retention of the BIPAP mode of SB can reduce the risk of lung injury and improve respiratory function.

Mouse Model of Oleic Acid-Induced Acute Respiratory Distress Syndrome.

Acute respiratory distress syndrome (ARDS) is a significant threat to critically ill patients with a high fatality rate. Pollutant exposure, cigarette smoke, infectious agents, and fatty acids can induce ARDS. Animal models can mimic the complex pathomechanism of the ARDS. However, each of them has limitations. Notably, oleic acid (OA) is increased in critically ill patients with harmful effects on the lung. OA can induce lung injury by emboli, disrupting tissue, altering pH, and impairing edema clearance. OA-induced lung injury model resembles various features of ARDS with endothelial injury, increased alveolar permeability, inflammation, membrane hyaline formation, and cell death. Herein, induction of lung injury is described by injecting OA (in salt form) directly into the lung and intravenously in a mouse since it is the physiological form of OA at pH 7. Thus, the injection of OA in the salt form is a helpful animal model to study lung injury/ARDS without causing emboli or altering the pH, thereby getting close to what is happening in critically ill patients.

Therapeutic hypothermia attenuates physiologic, histologic, and metabolomic markers of injury in a porcine model of acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a lung injury characterized by noncardiogenic pulmonary edema and hypoxic respiratory failure. The purpose of this study was to investigate the effects of therapeutic hypothermia on short‐term experimental ARDS. Twenty adult female Yorkshire pigs were divided into four groups (n = 5 each): normothermic control (C), normothermic injured (I), hypothermic control (HC), and hypothermic injured (HI). Acute respiratory distress syndrome was induced experimentally via intrapulmonary injection of oleic acid. Target core temperature was achieved in the HI group within 1 h of injury induction. Cardiorespiratory, histologic, cytokine, and metabolomic data were collected on all animals prior to and following injury/sham. All data were collected for approximately 12 h from the beginning of the study until euthanasia. Therapeutic hypothermia reduced injury in the HI compared to the I group (histological injury score = 0.51 ± 0.18 vs. 0.76 ± 0.06; p = 0.02) with no change in gas exchange. All groups expressed distinct phenotypes, with a reduction in pro‐inflammatory metabolites, an increase in anti‐inflammatory metabolites, and a reduction in inflammatory cytokines observed in the HI group compared to the I group. Changes to respiratory system mechanics in the injured groups were due to increases in lung elastance (E) and resistance (R) (ΔE from pre‐injury = 46 ± 14 cmH2O L−1, p < 0.0001; ΔR from pre‐injury: 3 ± 2 cmH2O L−1 s−, p = 0.30) rather than changes to the chest wall (ΔE from pre‐injury: 0.7 ± 1.6 cmH2O L−1, p = 0.99; ΔR from pre‐injury: 0.6 ± 0.1 cmH2O L−1 s−, p = 0.01). Both control groups had no change in respiratory mechanics. In conclusion, therapeutic hypothermia can reduce markers of injury and inflammation associated with experimentally induced short‐term ARDS.

Lung-brain 'cross-talk': systemic propagation of cytokines in the ARDS via the bloodstream using a blood transfusion model does not influence cerebral inflammatory response in pigs.

BackgroundInterorgan cross-talk describes the phenomenon in which a primarily injured organ causes secondary damage to a distant organ. This cross-talk is well known between the lung and brain. One theory suggests that the release and systemic distribution of cytokines via the bloodstream from the primarily affected organ sets in motion proinflammatory cascades in distant organs. In this study, we analysed the role of the systemic distribution of cytokines via the bloodstream in a porcine ARDS model for organ cross-talk and possible inflammatory changes in the brain.MethodsAfter approval of the State and Institutional Animal Care Committee, acute respiratory distress syndrome (ARDS) induction with oleic acid injection was performed in seven animals. Eight hours after ARDS induction, blood (35–40 ml kg–1) was taken from these seven ‘ARDS donor’ pigs. The collected ‘ARDS donor’ blood was transfused into seven healthy ‘ARDS-recipient’ pigs. Three animals served as a control group, and blood from these animals was transfused into three healthy pigs after an appropriate ventilation period. All animals were monitored for 8 h using advanced cardiorespiratory monitoring. Postmortem assessment included cerebral (hippocampal and cortex) mediators of early inflammatory response (IL-6, TNF-alpha, iNOS, sLCN-2), wet-to-dry ratio and lung histology. TNF-alpha serum concentration was measured in all groups.ResultsARDS was successfully induced in the ‘ARDS donor’ group, and serum TNF-alpha levels were elevated compared with the ‘ARDS-recipient’ group. In the ‘ARDS-recipient’ group, neither significant ARDS alterations nor upregulation of inflammatory mediators in the brain tissue were detected after high-volume random allogenic ‘ARDS-blood’ transfusion. The role of the systemic distribution of inflammatory cytokines from one affected organ to another could not be confirmed in this study.

Influence of rosuvastatin treatment on cerebral inflammation and nitro-oxidative stress in experimental lung injury in pigs

BackgroundMany patients with acute respiratory distress syndrome (ARDS) suffer from cognitive impairment after hospital discharge. Different mechanisms have been implicated as potential causes for this impairment, inter alia cerebral inflammation. A class of drugs with antioxidant and anti-inflammatory properties are β-HMG-CoA-reductase inhibitors (“statins”). We hypothesized that treatment with rosuvastatin attenuates cerebral cytokine mRNA expression and nitro-oxidative stress in an animal model of acute lung injury.MethodsAfter approval of the institutional and state animal care committee, we performed this prospective randomized controlled animal study in accordance with the international guidelines for the care and use of laboratory animals. Thirty-two healthy male pigs were randomized to one of four groups: lung injury by central venous injection of oleic acid (n = 8), statin treatment before and directly after lung injury (n = 8), statin treatment after lung injury (n = 8), or ventilation-only controls (n = 8). About 18 h after lung injury and standardized treatment, the animals were euthanised, and the brains and lungs were collected for further examinations. We determined histologic lung injury and cerebral and pulmonal cytokine and 3-nitrotyrosine production.ResultsWe found a significant increase in hippocampal IL-6 mRNA after lung injury (p < 0.05). Treatment with rosuvastatin before and after induction of lung injury led to a significant reduction of hippocampal IL-6 mRNA (p < 0.05). Cerebral 3-nitrotyrosine was significantly higher in lung-injured animals compared with all other groups (p < 0.05 vs. animals treated with rosuvastatin after lung injury induction; p < 0.001 vs. all other groups). 3-Nitrotyrosine was also increased in the lungs of the lung-injured pigs compared to all other groups (p < 0.05 each).ConclusionsOur findings highlight cerebral cytokine production and nitro-oxidative stress within the first day after induction of lung injury. The treatment with rosuvastatin reduced IL-6 mRNA and 3-nitrotyrosine concentration in the brains of the animals. In earlier trials, statin treatment did not reduce mortality in ARDS patients but seemed to improve quality of life in ARDS survivors. Whether this is attributable to better cognitive function because of reduced nitro-oxidative stress and inflammation remains to be elucidated.

Role of insulin in oleic acid-induced acute lung injury in rat model

Objectives: Acute lung injury (ALI) is an inflammatory condition, therefore, this study was undertaken to determine the effect of insulin (an immunomodulatory agent) in oleic acid (OA)-induced ALI in rat model. Materials and Methods: The experiments were performed on adult male albino rats (total n = 18). The trachea, jugular vein and carotid artery of anaesthetised adult rats were cannulated to keep the respiratory tract patent, deliver saline/drugs and recording of blood pressure, respectively. Animals were divided into three groups. In Group I (control group), normal saline (75 μL) was injected and this group served as control group. In Group II (OA group), OA (75 μL) was administered to induce ALI in rats. In Group III (insulin + OA), OA (75 μL) was injected in insulin pre-treated rats. Respiratory frequency (RF), heart rate (HR) and mean arterial pressure (MAP) were recorded on computerised chart recorder; arterial blood sample was collected to determine PaO2/FiO2. Further, pulmonary water content was determined, and histological examination of the lung was done in all animals. Results: Injection of OA produced ALI indicated by significant increase in RF by 30 min followed by progressive decrease and ultimately death of animal. Significant increase in the pulmonary water content and decrease in PaO2/FiO2 were observed in these animals. Histological examination of lungs showed damage to the lung parenchyma. An immediate decrease in HR and MAP followed by some improvement and then progressive decrease was also observed. Conclusions: Insulin (an immunomodulatory agent) pre-treatment delayed initiation of OA-induced ALI as indicated by protection against OA-induced severe alteration in the RF in the initial stage and less lung injury in histological examination, although; it could not alter the overall course of the disease.

Renal Function and Pulmonary Fluid Balance in Porcine Models of Acute Lung Injury

Managing pulmonary edema is critical to maintaining blood oxygenation and perfusion for adequate tissue oxygen delivery after acute lung injury. While it is well recognized that renal failure often leads to complications of nephrogenic pulmonary edema, how the regulation of lung fluid is changed during altered renal function in conditions of traumatic injury is poorly understood. We hypothesized that control of lung water balance after a traumatic blunt force lung injury accompanied by a renal response to hemorrhage and hypotension would be different than after simple disruption of the alveolar-capillary liquid barrier interface. Hence, we compared the changes in effective lung water index (ELWI, measured by the Pulse Ion Contour Cardiac Output (PICCO), Getinge) method in a pig model of Traumatic Acute Lung Injury (TALI, n=9), and a model of diffuse alveolar-capillary barrier disruption with oleic acid (OA, n=5), versus a control group (n=10). Anesthetized, mechanically ventilated, Yorkshire cross male and female pigs (body weight 27.0 +/- 0.6 kg) were catheterized with a Swan Ganz catheter for measurement of pulmonary artery pressure and cardiac output determination by thermodilution. Pulmonary function, hemodynamics, and urinary output were examined before and after localized blunt right chest trauma (TALI), or oleic acid injection into the main pulmonary artery (OA 0.3 ml in 50% w/v ethanol). Pulmonary vasoconstriction was induced in the acute lung injury groups as indicated by an increase in pulmonary to systemic vascular resistance ratios in TALI (0.37 +/- 0.03) and OA (0.34 +/-0.08) compared to controls (0.21+/-0.02). TALI resulted in a decrease in mean arterial pressure (MAP, 46+/-4 mmHg) compared to controls (60 +/-2 mmHg) or OA (62+/-3 mm Hg). In all groups ELWI remained steady compared to pre-injury baseline. In the OA and control groups, circulating vasopressin decreased over the time course of the experiment (p<0.01) but did not decrease in the TALI group in accordance with the injury-induced hemorrhage and decreased MAP. Accordingly, urine flow decreased in the TALI group compared to OA and controls. Fractional excretion of water decreased in the OA and control groups, (p<0.01) but remained unchanged in TALI, indicating retention of water in OA and controls compared to TALI. The overall maintenance of ELWI despite differences in renal water handling in TALI compared to controls suggest that protection against pulmonary edema needs to be considered in treatment of hypotension with fluid resuscitation in traumatic lung injury.

Effect of Therapeutic Hypothermia on Physiologic, Histologic and Metabolomic Markers of Lung Injury in Experimental Acute Respiratory Distress Syndrome

Background Acute respiratory distress syndrome (ARDS) is a severe lung injury characterized by noncardiogenic pulmonary edema and rapid hypoxic respiratory failure. Therapeutic hypothermia improves outcomes of traumatic brain injury and cardiac injuries; however, it has not been widely used or studied in ARDS. Hypothermia may be helpful in reducing injury and inflammation associated with ARDS by reducing pro-inflammatory molecule production. Objective To evaluate the effect of therapeutic hypothermia on the development of injury and inflammation in experimental, short-term ARDS. Hypothesis Hypothermia induced at the onset of lung injury would mitigate histological and serum metabolic changes, as well as changes in respiratory elastance (E) and resistance (R). Methods The Animal Research Committee of the University of British Columbia approved all experimental procedures. Twenty female Yorkshire pigs were divided into 4 groups (n= 5 per group): normothermic control (C), normothermic injured (I), hypothermic control (HC), and hypothermic injured (HI). ARDS was induced via intrapulmonary injection of oleic acid. Hypothermia was induced with a cooling catheter placed into the left jugular vein. The normothermic groups had core temperatures maintained at 36.5-38°C and the hypothermic groups were cooled to 32°C. Animals were euthanized after a 12-hour follow-up period. Respiratory mechanical variables were quantified based the measurements of flow, airway pressure, and esophageal pressure. Tissue samples from the right diaphragmatic lobe were collected after euthanasia and examined for injury score. Plasma samples were collected and 1H-NMR spectroscopy analysis was performed to determine metabolite concentration. Results Therapeutic hypothermia reduced injury in the HI vs. I group (injury score= 0.51±0.18 vs. 0.76±0.06; p<0.05). All cohorts expressed distinct phenotypes with the HI cohort having a reduction in inflammatory metabolites (i.e., succinate) compared to the I cohort. Changes to respiratory mechanics were due to changes in lung E and R (ΔE from pre-injury= 45.55±14.17 cmH2O·l-1; ΔR from pre-injury= 3.07±1.99 cmH2O·l-1·s-1, p<0.05) and not chest-wall E and R (ΔE from pre-injury= 0.73±1.59 cmH2·l-1; ΔR from pre-injury= 0.59±0.14 cmH2O·l-1s-1, p>0.05), with trends for the HI group to have a lower lung R (p=0.99) and E (p=0.93) compared to the I group. Control groups showed no significant change in respiratory mechanics. Conclusion Therapeutic hypothermia canreduce some markers of injury and inflammation associated with ARDS. Further studies are required to determine the effect on longer term outcomes and mortality.

Experimental lung injury induces cerebral cytokine mRNA production in pigs.

BackgroundAcute respiratory distress syndrome (ARDS) is an important disease with a high incidence among patients admitted to intensive care units. Over the last decades, the survival of critically ill patients has improved; however, cognitive deficits are among the long-term sequelae. We hypothesize that acute lung injury leads to upregulation of cerebral cytokine synthesis.MethodsAfter approval of the institutional and animal care committee, 20 male pigs were randomized to one of three groups: (1) Lung injury by oleic acid injection (OAI), (2) ventilation only (CTR) or (3) untreated. We compared neuronal numbers, proportion of neurons with markers for apoptosis, activation state of Iba-1 stained microglia cells and cerebral mRNA levels of different cytokines between the groups 18 hours after onset of lung injury.ResultsWe found an increase in hippocampal TNFalpha (p < 0.05) and IL-6 (p < 0.05) messenger RNA (mRNA) in the OAI compared to untreated group as well as higher hippocampal IL-6 mRNA compared to control (p < 0.05). IL-8 and IL-1beta mRNA showed no differences between the groups. We found histologic markers for beginning apoptosis in OAI compared to untreated (p < 0.05) and more active microglia cells in OAI and CTR compared to untreated (p < 0.001 each).ConclusionHippocampal cytokine transcription increases within 18 hours after the induction of acute lung injury with histological evidence of neuronal damage. It remains to be elucidated if increased cytokine mRNA synthesis plays a role in the cognitive decline observed in survivors of ARDS.

Oleic Acid, Cholesterol, and Linoleic Acid as Angiogenesis Initiators.

The current study determined the natural angiogenic molecules using an unbiased metabolomics approach. A chick chorioallantoic membrane (CAM) model was used to examine pro- and antiangiogenic molecules, followed by gas chromatography–mass spectrometry (GCMS) analysis. Vessel formation was analyzed quantitatively using the angiogenic index (p < 0.05). At embryonic day one, a white streak or circle area was observed when vessel formation begins. GCMS analysis and database search demonstrated that angiogenesis may initiate when oleic, cholesterol, and linoleic acids increased in the area of angiogenic reactions. The gain of function study was conducted by the injection of cholesterol and oleic acid into a chick embryo to determine the role of each lipid in angiogenesis. We propose that oleic acid, cholesterol, and linoleic acid are natural molecules that set the platform for the initiation stage of angiogenesis before other proteins including the vascular endothelial growth factor, angiopoietin, angiotensin, and erythropoietin join as the angiome in sprout extension and vessel maturation.

Effect of positive end-expiratory pressure on functional residual capacity in two experimental models of acute respiratory distress syndrome.

ObjectiveMeasurement of positive end-expiratory pressure (PEEP)-induced recruitment lung volume using passive spirometry is based on the assumption that the functional residual capacity (FRC) is not modified by the PEEP changes. We aimed to investigate the influence of PEEP on FRC in different models of acute respiratory distress syndrome (ARDS).MethodsA randomized crossover study was performed in 12 pigs. Pulmonary (n = 6) and extra-pulmonary (n = 6) ARDS models were established using an alveolar instillation of hydrochloric acid and a right atrium injection of oleic acid, respectively. Low (5 cmH2O) and high (15 cmH2O) PEEP were randomly applied in each animal. FRC and recruitment volume were determined using the nitrogen wash-in/wash-out technique and release maneuver.ResultsFRC was not significantly different between the two PEEP levels in either pulmonary ARDS (299 ± 92 mL and 309 ± 130 mL at 5 and 15 cmH2O, respectively) or extra-pulmonary ARDS (305 ± 143 mL and 328 ± 197 mL at 5 and 15 cmH2O, respectively). The recruitment volume was not significantly different between the two models (pulmonary, 341 ± 100 mL; extra-pulmonary, 351 ± 170 mL).ConclusionsPEEP did not influence FRC in either the pulmonary or extra-pulmonary ARDS pig model.

Bronchoalveolar Lavage and Oleic Acid-Injection in Pigs as a Double-Hit Model for Acute Respiratory Distress Syndrome (ARDS).

The treatment of ARDS continues to pose major challenges for intensive care physicians in the 21st century with mortality rates still reaching up to 50% in severe cases. Further research efforts are needed to better understand the complex pathophysiology of this disease. There are different well-established animal models to induce acute lung injury but none has been able to adequately mimic the complex pathomechanisms of ARDS. The most crucial factor for the development of this condition is the damage to the alveolar capillary unit. The combination of two well-established lung injury models allow us to mimic in more detail the underlying pathomechanism. Bronchoalveolar lavage (BAL) leads to surfactant depletion as well as alveolar collapse. The repeated instillation of fluid volumes causes subsequent hypoxemia. Surfactant depletion is a key factor of ARDS in humans. BAL is often combined with other lung injury approaches, but not with a second hit followed by oleic acid injection (OAI) yet. Oleic acid injection leads to severely impaired gas exchange, a deterioration of lung mechanics and disruption of the alveolo-capillary barrier. The OAI mimics most of the expected effects of ARDS consisting of extended inflammation of lung tissue with an increase of alveolar leakage and gas exchange impairment. A disadvantage of the combination of different models is the difficulty to determine the influence to the lung injury caused by BAL alone, OAI alone or both together. The model presented in this report represents the combination of BAL and OAI as a new double-hit lung injury model. This new model is easy to implement and an alternative to study different therapeutic approaches in ARDS in the future.

Glibenclamide alleviates inflammation in oleic acid model of acute lung injury through NLRP3 inflammasome signaling pathway.

Background: Pulmonary fat embolism (PFE) is one of the important causes of acute lung injury (ALI), but its pathogenesis is unclear. In recent years, it has been found that the NLRP3 inflammasome is closely related to inflammatory response. However, there are no reports about the involvement of NLRP3 in PFE- associated ALI. Glibenclamide is a kind of hypoglycaemic drug with anti-inflammatory effect. It has been reported to have the anti-inflammatory effect related to inhibiting NLRP3.Objective: To determine whether NLRP3 inflammasome was involved in ALI induced by PFE or whether glibenclamide had therapeutic effects on such lung injury, we designed this experiment.Materials and methods: The rat model of intravenous injection of oleic acid (OA) was used to simulate PFE. Rats were divided into three groups: control, OA and glibenclamide treatment group. Blood free fatty acid (FFA) concentration was determined by ACS-ACOD. Histopathological examinations were taken to assess the severity of lung injury. The expression of NLRP3 pathway and its downstream products were analyzed by IHC, WB, qPCR and ELISA.Results: Four hours after intravenous OA injection, the typical pathological manifestations of ALI accompanied by elevated levels of plasma FFAs were found. The activity of NLRP3 inflammasomes increased in OA group, too. Pretreatment with glibenclamide partly inhibited the increase in NLRP3, caspase-1 and IL-1β expression induced by OA, simultaneously attenuated the lung injury. But it has little effect on the expression of Toll-like receptor 4 (TLR4) expression in this experiment.Conclusion: NLRP3 inflammasome, one of the main components of innate immune response, involved in ALI induced by OA. Glibenclamide can alleviate this kind of ALI by inhibiting rather the NLRP3/caspase-1/IL-1β signaling pathway than the levels of FFAs or TLR4 pathway.

Dietary Omega-3 Polyunsaturated Fatty Acid Deprivation Does Not Alter Seizure Thresholds but May Prevent the Anti-seizure Effects of Injected Docosahexaenoic Acid in Rats.

Background: Brain concentrations of omega-3 docosahexaenoic acid (DHA, 22:6n-3) have been reported to positively correlate with seizure thresholds in rodent seizure models. It is not known whether brain DHA depletion, achieved by chronic dietary omega-3 polyunsaturated fatty acid (PUFA) deficiency, lowers seizure thresholds in rats.Objective: The present study tested the hypothesis that lowering brain DHA concentration with chronic dietary n-3 PUFA deprivation in rats will reduce seizure thresholds, and that compared to injected oleic acid (OA), injected DHA will raise seizure thresholds in rats maintained on n-3 PUFA adequate and deficient diets.Methods: Rats (60 days old) were surgically implanted with electrodes in the amygdala, and subsequently randomized to the AIN-93G diet containing adequate levels of n-3 PUFA derived from soybean oil or an n-3 PUFA-deficient diet derived from coconut and safflower oil. The rats were maintained on the diets for 37 weeks. Afterdischarge seizure thresholds (ADTs) were measured every 4–6 weeks by electrically stimulating the amygdala. Between weeks 35 and 37, ADTs were assessed within 1 h of subcutaneous OA or DHA injection (600 mg/kg). Seizure thresholds were also measured in a parallel group of non-implanted rats subjected to the maximal pentylenetetrazol (PTZ, 110 mg/kg) seizure test. PUFA composition was measured in the pyriform-amygdala complex of another group of non-implanted rats sacrificed at 16 and 32 weeks.Results: Dietary n-3 PUFA deprivation did not significantly alter amygdaloid seizure thresholds or latency to PTZ-induced seizures. Acute injection of OA did not alter amygdaloid ADTs of rats on the n-3 PUFA adequate or deficient diets, whereas acute injection of DHA significantly increased amygdaloid ADTs in rats on the n-3 PUFA adequate control diet as compared to rats on the n-3 PUFA deficient diet (P < 0.05). Pyriform-amygdala DHA percent composition did not significantly differ between the groups, while n-6 docosapentaenoic acid, a marker of n-3 PUFA deficiency, was significantly increased by 2.9-fold at 32 weeks.Conclusion: Chronic dietary n-3 PUFA deficiency does not alter seizure thresholds in rats, but may prevent the anti-seizure effects of DHA.

Tanshinone IIA ameliorates acute lung injury by inhibition of the NLRP3 inflammasome

Tanshinone IIA is the phenanthrenequinone derivative extracted from the perennial plant Salvia miltiorrhiza Bunge (red sage). We investigated whether inhibition of the nucleotide-binding oligomerization domain (NOD)-like receptor family protein 3 (NLRP3) inflammasome mediates the protective effect of tanshinone IIA in acute lung injury (ALI) induced in rats by oleic acid (OA) injection. Compared with the control treatment, OA injection induced pulmonary histological impairment, increased the lung wet/dry weight ratio (7.0?1.1 vs 4.?0.6 ) and CO2 partial pressure (PaCO2) (52?6.4 vs 40?3.6 mmHg), decreased arterial O2 partial pressure (PaO2) (63?8.4 vs 100?3.0 mmHg), and increased tumor necrosis factor ? (TNF?) (8.8?2.3 vs 5.2 ?1.5 pg/mL), monocyte chemoattractant protein-1 (MCP-1) (36.1?4.9 vs 25.2?6.6 pg/mL) and interleukin-1? (IL-1?) (15.9?3.2 vs 4.6?1.3 pg/mL) in the bronchoalveolar lavage (BAL) fluid. Tanshinone IIA provided protection against ALI, observed as a reduction in the lung wet/dry weight ratio and CO2 partial pressure, and increased O2 partial pressure. The cytokine increase was also prevented. Tanshinone IIA attenuated increased protein levels of NLRP3, caspase-1 and IL-1? in pulmonary tissues, suggesting that it ameliorates ALI by preventing NLRP3 inflammasome activation.

Oleic Acid-Injection in Pigs As a Model for Acute Respiratory Distress Syndrome.

The acute respiratory distress syndrome is a relevant intensive care disease with an incidence ranging between 2.2% and 19% of intensive care unit patients. Despite treatment advances over the last decades, ARDS patients still suffer mortality rates between 35 and 40%. There is still a need for further research to improve the outcome of patients suffering from ARDS. One problem is that no single animal model can mimic the complex pathomechanism of the acute respiratory distress syndrome, but several models exist to study different parts of it. Oleic acid injection (OAI)-induced lung injury is a well-established model for studying ventilation strategies, lung mechanics and ventilation/perfusion distribution in animals. OAI leads to severely impaired gas exchange, deterioration of lung mechanics and disruption of the alveolo-capillary barrier. The disadvantage of this model is the controversial mechanistic relevance of this model and the necessity for central venous access, which is challenging especially in smaller animal models. In summary, OAI-induced lung injury leads to reproducible results in small and large animals and hence represents a well-suited model for studying ARDS. Nevertheless, further research is necessary to find a model that mimics all parts of ARDS and lacks the problems associated with the different models existing today.

Oleic Acid-Injection in Pigs As a Model for Acute Respiratory Distress Syndrome

Oleic Acid-Injection in Pigs As a Model for Acute Respiratory Distress Syndrome