Oleic Acid-induced Acute Lung Injury Research Articles

Differential changes in expression of inflammatory mRNA and protein after oleic acid-induced acute lung injury

Background: Acute Respiratory Distress syndrome (ARDS) is a clinical syndrome of noncardiac pulmonary edema and inflammation leading to acute respiratory failure. We used the oleic acid infusion pig model of ARDS resembling human disease to explore cytokine changes in white blood cells (WBC) and plasma proteins, comparing baseline to ARDS values. Methods: Nineteen juvenile female swine were included in the study. ARDS defined by a PaO2/FiO2 ratio < 300 was induced by continuous oleic acid infusion. Arterial blood was drawn before and during oleic acid infusion, and when ARDS was established. Cytokine expression in WBC was analyzed by RT-qPCR and plasma protein expression by ELISA. Results: The median concentration of IFN-γ mRNA was estimated to be 59% (p = 0.006) and of IL-6 to be 44.4% (p = 0.003) of the baseline amount. No significant changes were detected for TNF-α, IL-17, and IL-10 mRNA expression. In contrast, the concentrations of plasma IFN-γ and IL-6 were significantly higher (p = 0.004 and p = 0.048 resp.), and TNF-α was significantly lower (p = 0.006) at ARDS compared to baseline. Conclusions: The change of proinflammatory cytokines IFN-γ and IL-6 expression is different comparing mRNA and plasma proteins at oleic acid-induced ARDS compared to baseline. The migration of cells to the lung may be the cause for this discrepancy.

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.

Irbesartan eases lipopolysaccharide-induced lung injury In Vitro and In Vivo.

Acute lung injury (ALI) is classified as a devastating pulmonary disorder contributing to significant incidence and fatality rate. Irbesartan (IRB) is an angiotensin II receptor blocker that has been proposed to protect against oleic acid-induced ALI. To this end, the current study is concentrated on ascertaining the role of IRB in ALI and figuring out the probable action mechanism. First, cell counting kit-8 (CCK-8) appraised the viability of human pulmonary microvascular endothelial cells (HPMVECs) exposed to ascending concentrations of IRB. HPMVEC injury model and a mouse model of ALI induced by lipopolysaccharide (LPS) were pretreated by IRB. In vitro, cell viability was estimated by CCK-8 assay, and lactate dehydrogenase (LDH) release was tested by LDH assay kit. Enzyme-linked immunosorbent assay (ELISA) and Western blotting estimated the expression levels of inflammatory factors. Fluorescein isothiocyanate-dextran was used to assess HPMVEC permeability. Western blotting examined the expression of adherent and tight junction proteins. In vivo, hematoxylin and eosin staining evaluated lung tissue damage and lung wet/dry (W/D) weight was measured. ELISA analyzed the levels of inflammatory factors in the serum and bronchoalveolar lavage fluid (BALF), and Western blotting examined the expression of inflammatory factors. The total cell, neutrophil, and macrophage numbers in BALF were determined using a cell counter. Lung capillary permeability was assayed by Evans blue albumin and total protein concentration in BALF was measured using bicinchoninic acid method. Immunofluorescence assay and Western blotting examined the expression of adherent and tight junction proteins in lung tissues. It was observed that IRB dose-dependently enhanced the viability while reduced LDH release, inflammatory response as well as permeability in LPS-challenged HPMVECs in vitro. In addition, LPS-stimulated lung tissue damage, pulmonary edema, inflammatory response as well as lung capillary permeability in vivo were all reversed following IRB treatment. Collectively, IRB treatment might elicit protective behaviors against LPS-triggered ALI.

Prevention of mortality in acute lung injury induced by oleic acid: Application of polyherbal decoction (bronco T).

Acute lung injury (ALI) is a lethal respiratory disorder; directed uncontrolled inflammation, sloughing of the alveolar cells and their diffusion, and altered cardiorespiratory parameters with a global mortality rate of 40%. This study was designed to assess the preventive effect of a polyherbal decoction (Bronco T, 1.5 g/kg b. w.) on cardiorespiratory variables in oleic acid-induced ALI in rats. Oleic acid increases the level of neutrophil infiltration leading to pulmonary edema and alters the cardiorespiratory dynamics. The adult male rats were surgically cannulated and treated with intravenous oleic acid (0.38 ml/kg b. w.) to establish the ALI model. Bronco T was pre-administered orally 3 hours before oleic acid. The biophysical, histological, biochemical, and molecular effects were compared with dexamethasone (5 mg/kg b. w. i. p.). The animals were randomly divided into control, lethal, standard, and treatment groups. Respiratory frequency (RF), heart rate (HR), and mean arterial pressure (MAP) were recorded on a computerized chart recorder; arterial blood sample was collected to determine PaO2/FiO2, TNF-α, and MPO. Lipid peroxidation, superoxide dismutase, and catalase activity were evaluated to measure oxidative stress in bronchoalveolar lavage. Additionally, the pulmonary water content, COX-2 expression and histological examination were determined in the lung. A molecular docking study of the active phytoconstituent of BT obtained from HR-LCMS analysis against reported targets (IL-6, COX-2, TNFα, MPO and ENaC) of ALI was carried out. The B.T. pretreatment prevents mortality in comparison to the oleic acid group. It protects the lungs and heart from the detrimental effect of oleic acid, on par with dexamethasone. COX-2 mRNA expression was significantly down-regulated in the treatment group. The reduced level of TNF-α, MPO, SOD and catalase supported the protective effect of B.T. The in silico study revealed strong binding interaction between the phytoconstituent (Galangin 3- [galactosyl-(1–4)-rhamnoside and Beta solamarine] of BT and the reported target. The B.T. pre-administration attenuates the oleic acid-induced mortality and cardiorespiratory toxicity.

The Role of Antioxidant Agent (N-Acetylcysteine) in Oleic Acid-Induced Acute Lung Injury in a Rat Model.

ContextReactive oxygen species (ROS) produced by inflammatory cells play a major role in mediating lung injury in sepsis or hyperoxic lung injury.AimsN-Acetylcysteine (NAC), an antioxidant, was examined in this research to see whether it helps prevent acute lung injury (ALI).Materials and methodsExperiments were performed on Charles-Foster strain healthy male adult albino rats. All the animals were randomly divided into one control and two experimental groups. In control/group I, saline was administered, and cardiorespiratory parameters were recorded. Oleic acid (OA) was administered in group II to produce ALI. In group III, OA was administered to NAC-pretreated rats, and cardiorespiratory parameters were recorded to observe the effect of NAC on ALI. This study used analysis of variance (ANOVA) with two factors and a post hoc test (multiple comparisons - least significant difference (LSD) test) for statical analysis. For determining survival time, the Mantel-Cox test and Kaplan-Meier survival curves were used. A P value < 0.05 was considered significant.ResultsRespiratory arrest, pulmonary edema, and reduced partial pressure of oxygen (PaO2)/fraction of inspired oxygen (FiO2) ratio were all indications of OA-induced ALI in rats. The animals in the NAC + OA group had better respiratory and cardiac statistics than those in the OA alone group, and their survival duration was extended. However, NAC pretreatment could not protect the animals against the development of pulmonary edema.ConclusionsThese observations indicate that NAC (an antioxidant agent) protected rats against ALI in the initial phase and prolonged the survival time but failed to prevent the development of pulmonary edema.

SAT054 - Oleic acid-induced acute lung injury in Ob/Ob mice fed with high-fat-diet exacerbate bile acid uptake and liver injury that was reversed by antagonizing their entry

SAT054 - Oleic acid-induced acute lung injury in Ob/Ob mice fed with high-fat-diet exacerbate bile acid uptake and liver injury that was reversed by antagonizing their entry

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.

Knockout of PKC θ gene attenuates oleic acid-induced acute lung injury via reduction of inflammation and oxidative stress.

Objective(s):Acute respiratory distress syndrome resulting from acute lung injury has become a momentous clinical concern because of high morbidity and mortality in discharged patients with pulmonary and nonpulmonary diseases. This study aimed to explore the effect of protein kinase C (PKC) θ gene knockout on acute lung injury.Materials and Methods:Wt and PKC θ gene knockout mice were intravenously injected with oleic acid to induce acute lung injury. Pulmonary capillary permeability was assessed via measuring lung wet/dry weight ratio and level of protein in bronchoalveolar lavage fluid (BALF). Histological changes were used to examine acute lung injury. Malondialdehyde (MDA) level, superoxide dismutase (SOD) activity in serum, together with inflammatory cytokines including interleukin (IL)-6 and tumor necrosis factor-alpha (TNF-α), were determined. Furthermore, the expressions of heme oxygenase (HO)-1, nuclear factor kappa B (NF κB), and inhibitor of NF-κB alpha (IκB α) were detected in the lungs.Results:PKC θ gene knockout decreased lung wet/dry weight ratio, reduced levels of MDA, IL-6, and TNF-α in serum together with level of protein in BALF. Furthermore, PKC θ gene knockout increased the activities of SOD. Knockout of PKC θ was also observed to increase expression of HO-1 and reduce levels of p-NF κB and p-IKB α in the lungs.Conclusion:These results suggest that PKC θ gene knockout attenuates oleic acid-induced acute lung injury via improving oxidative stress and inflammation.

Colchicine reduces lung injury in experimental acute respiratory distress syndrome.

The acute respiratory distress syndrome (ARDS) is characterized by intense dysregulated inflammation leading to acute lung injury (ALI) and respiratory failure. There are no effective pharmacologic therapies for ARDS. Colchicine is a low-cost, widely available drug, effective in the treatment of inflammatory conditions. We studied the effects of colchicine pre-treatment on oleic acid-induced ARDS in rats. Rats were treated with colchicine (1 mg/kg) or placebo for three days prior to intravenous oleic acid-induced ALI (150 mg/kg). Four hours later they were studied and compared to a sham group. Colchicine reduced the area of histological lung injury by 61%, reduced lung edema, and markedly improved oxygenation by increasing PaO2/FiO2 from 66 ± 13 mmHg (mean ± SEM) to 246 ± 45 mmHg compared to 380 ± 18 mmHg in sham animals. Colchicine also reduced PaCO2 and respiratory acidosis. Lung neutrophil recruitment, assessed by myeloperoxidase immunostaining, was greatly increased after injury from 1.16 ± 0.19% to 8.86 ± 0.66% and significantly reduced by colchicine to 5.95 ± 1.13%. Increased lung NETosis was also reduced by therapy. Circulating leukocytosis after ALI was not reduced by colchicine therapy, but neutrophils reactivity and CD4 and CD8 cell surface expression on lymphocyte populations were restored. Colchicine reduces ALI and respiratory failure in experimental ARDS in relation with reduced lung neutrophil recruitment and reduced circulating leukocyte activation. This study supports the clinical development of colchicine for the prevention of ARDS in conditions causing ALI.

Keratinocyte Growth Factor-2 Is Protective in Oleic Acid-Induced Acute Lung Injury in Rats.

Objective The aim of this study was to examine the role of keratinocyte growth factor-2 (KGF-2) in oleic acid-induced acute lung injury (ALI) in rats. Methods Forty-five healthy adult male Sprague Dawley rats were divided into 3 groups. Rat ALI model was established by injection of 0.01 mL/kg oleic acid into the tail vein. Rats in the control group were injected with the same amount of normal saline (NS). In the ALI + KGF-2 group, 5 mg/kg of KGF-2 was instilled into the airway of rats 72 hours before the model preparation, and the control group and the ALI model group were instilled with the same amount of NS. The lung permeability index (LPI) and lung wet/dry weight (W / D) ratios were measured 8 hours after the model preparation. The permeability of pulmonary microvascular endothelium was evaluated by Evans blue leakage test. Histopathological changes were observed under light microscope and the ALI pathology score (LIS) was calculated. Ultrastructural changes of lung tissue were observed under electron microscope. The apoptosis was detected by TUNEL assay. The expression of Claudin-5, ZO-1, and VE Cadherin in lung tissue was qualitatively and quantitatively analyzed by immunohistochemistry, Western Blot, and qRT-PCR, respectively. Results The ALI model group had severe lung injury and obvious pathological changes, including alveolar septal thickening and inflammatory cell infiltration. TUNEL assay showed that the apoptosis of ALI group was significantly increased. The LIS score, lung W/D ratio, LPI, and Evans blue leakage were significantly higher than those in the control group; electron microscopy showed that the alveolar-capillary barrier was severely damaged in the ALI group. Compared with the control group, the expression of Claudin-5, ZO-1, and VE cadherin in the lung tissue of the ALI model group was significantly attenuated. After pretreatment with KGF-2, the degree of lung tissue damage was significantly reduced and the pathological changes were significantly improved. TUNEL assay showed that the apoptosis of ALI group was decreased. Lung W/D ratio, LPI, and Evans blue leakage decreased; electron microscopy showed that the alveolar-capillary barrier of ALI group recovered significantly. Compared with the ALI model group, the expression of Claudin-5, ZO-1, and VE cadherin in the lung tissue of the KGF-2 pretreatment group increased. Conclusion The results indicate that KGF-2 may attenuate oleic acid-induced ALI in rats by maintaining the pulmonary microvascular endothelial barrier, which is an effective ALI preventive measure.

Effects of propofol pretreatment on lung morphology and heme oxygenase-1 expression in oleic acid-induced acute lung injury in rats.

To investigate the effects of propofol pretreatment on lung morphology and heme oxygenase-1 expression in oleic acid -induced acute lung injury in rats. A total of 32 male Sprague-Dawley rats (250-300g) were randomly divided into the following four groups (n=8/group): group C, group OA, group OA+PR, and group OA+IX to compare related parameter changes. PaO2, PCO2, and PaO2/FiO2 were significantly different among the four treatment groups (P<0.05 or P<0.01). Lung wet/dry weight ratio and HO-1 protein expression also significantly differed among the groups (P<0.01). Immunohistochemistry showed that the expression of HO-1 in group OA+PR was stronger than those in groups OA, OA+IX, and C. Light microscopy revealed that pathological changes in lung tissues in group OA+PR were milder than those in group OA and group OA+IX. Electron microscopy showed that alveolar type II epithelial cell ultrastructure in group OA was relatively irregular with cell degeneration and disintegration and cytoplasmic lamellar bodies were vacuolized. Changes in group OA+PR were milder than those in group OA; however, they were more severe in group OA+IX than in group OA. Propofol significantly increases the expression of HO-1 in the lung tissueand prevents changes in lung morphology due to ALI in rats.

Colquhounia Root Tablet Protects Rat Pulmonary Microvascular Endothelial Cells against TNF-α-Induced Injury by Upregulating the Expression of Tight Junction Proteins Claudin-5 and ZO-1.

Background There are currently limited effective pharmacotherapy agents for acute lung injury (ALI). Inflammatory response in the lungs is the main pathophysiological process of ALI. Our preliminary data have shown that colquhounia root tablet (CRT), a natural herbal medicine, alleviates the pulmonary inflammatory responses and edema in a rat model with oleic acid-induced ALI. However, the potential molecular action mechanisms underlining its protective effects against ALI are poorly understood. This study aimed to investigate the effects and mechanism of CRT in rat pulmonary microvascular endothelial cells (PMEC) with TNF-α-induced injury. Methods PMECs were divided into 6 groups: normal control, TNF-α (10 ng/mL TNF-α), Dex (1×10−6 M Dex + 10 ng/mL TNF-α), CRT high (1000 ng/mL CRT + 10 ng/mL TNF-α), CRT medium (500 ng/mL CRT + 10 ng/mL TNF-α), and CRT low group (250 ng/mL CRT + 10 ng/mL TNF-α). Cell proliferation and apoptosis were detected by MTT assay and flow cytometry. Cell micromorphology was observed under transmission electron microscope. The localization and expression of tight junction proteins Claudin-5 and ZO-1 were analyzed by immunofluorescence staining and Western blot, respectively. Results TNF-a had successfully induced an acute endothelial cell injury model. Dex and CRT treatments had significantly stimulated the growth and reduced the apoptosis of PMECs (all p < 0.05 or 0.01) and alleviated the TNF-α-induced cell injury. The expression of Claudin-5 and ZO-1 in Dex and all 3 CRT groups was markedly increased compared with TNF-a group (all p < 0.05 or 0.01). Conclusion CRT effectively protects PMECs from TNF-α-induced injury, which might be mediated via stabilizing the structure of tight junction. CRT might be a promising, effective, and safe therapeutic agent for the treatment of ALI.

Effects of p38 mitogen-activated protein kinase in rats with oleic acid-induced acute lung injury

To study the effects of p38 mitogen-activated protein kinase (p38MAPK) signal transduction pathway inhibitor SB203580 on the inflammatory reaction and lung water clearance, and to explore the role of p38MAPK in acute lung injury, to provide new way for p38MAPK inhibitor -SB203580 intervene fat embolism syndrome induced lung injury. Twenty-four adult male SD rats were randomly assigned to normal control group (OA group) (n=8), oleic acid-induced lung injury group (OA group, n=8)and SB203580 pretreatment group (n=8). OA-group was administered oleic acid (0.20 ml/kg) via right jugular vein; In SB203580-group, SB203580(5 mg/kg) was injected via jugular vein, followed 30 min before by OA infusion; At the 4 hours animals were sacrificed. Arterial blood gas, the wet/dry weight(W/D)of the right lower lung were examined, lung index(LI), pulmonary permeability index(PPI) and levels of tumor necrosis factor α(TNF-α) in bronchoalveolar lavage fluid(BALF) were examined. The expressions of p38MAPK and phospho-p38MAPK (p-p38MAPK) were determined by Western blot and immunohistochemical method. Pathological changes of the lung tissue were examined with light microscrope. Compared to control group, arterial oxygen partial pressure (PaO2) and PaO2/FiO2 were decreased in the animals of OA-group, while right lower lung wet/dry ratio, lung index, PPI, levels of TNF-α in BALF and the protein expression of p-p38MAPK were increased significantly (P<0.01). The pathological changes were observed significantly in injured lung tissue. Compared to OA-group, those indexes were improved in SB203580 pretreated group. p38MAPK signal transaction path mediated inflammatory response process and played an important role in acute lung injury. SB203580 could inhibit the expression of inflammatory cytokines, reduce lung edema, protect lung tissue of rats from OA-induced lung injury obviously. Therefore, inhibition of p38MAPK activity provides a new way for the clinical treatment of fat embolism syndrome induced lung injury.

Regulation of epithelial sodium channel expression by oestradiol and progestogen in alveolar epithelial cells

Oestrogen (E) and progestogen (P) exert regulatory effects on the epithelial Na+ channel (ENaC) in the kidneys and the colon. However, the effects of E and P on the ENaC and on alveolar fluid clearance (AFC) remain unclear, and the mechanisms of action of these hormones are unknown. In this study, we showed that E and/or P administration increased AFC by more than 25% and increased the expression of the α and γ subunits of ENaC by approximately 35% in rats subjected to oleic acid-induced acute lung injury (ALI). A similar effect was observed in the dexamethasone-treated group. Furthermore, E and/or P treatment inhibited 11β-hydroxysteroid dehydrogenase (HSD) type 2 (11β-HSD2) activity, increased corticosterone expression and decreased the serum adrenocorticotrophic hormone (ACTH) levels. These effects were similar to those observed following treatment with carbenoxolone (CBX), a nonspecific HSD inhibitor. Further investigation showed that CBX further significantly increased AFC and α-ENaC expression after treatment with a low dose of E and/or P. In vitro, E or P alone inhibited 11β-HSD2 activity in a dose-dependent manner and increased α-ENaC expression by at least 50%, and E combined with P increased α-ENaC expression by more than 80%. Thus, E and P may augment the expression of α-ENaC, enhance AFC, attenuate pulmonary oedema by inhibiting 11β-HSD2 activity, and increase the active glucocorticoid levels in vivo and in vitro.

Endogeous sulfur dioxide protects against oleic acid-induced acute lung injury in association with inhibition of oxidative stress in rats

The role of endogenous sulfur dioxide (SO2), an efficient gasotransmitter maintaining homeostasis, in the development of acute lung injury (ALI) remains unidentified. We aimed to investigate the role of endogenous SO2 in the pathogenesis of ALI. An oleic acid (OA)-induced ALI rat model was established. Endogenous SO2 levels, lung injury, oxidative stress markers and apoptosis were examined. OA-induced ALI rats showed a markedly downregulated endogenous SO2/aspartate aminotransferase 1 (AAT1)/AAT2 pathway and severe lung injury. Chemical colorimetry assays demonstrated upregulated reactive oxygen species generation and downregulated antioxidant capacity in OA-induced ALI rats. However, SO2 increased endogenous SO2 levels, protected against oxidative stress and alleviated ALI. Moreover, compared with OA-treated cells, in human alveolar epithelial cells SO2 downregulated O2− and OH− generation. In contrast, L-aspartic acid-β-hydroxamate (HDX, Sigma-Aldrich Corporation), an inhibitor of endogenous SO2 generating enzyme, promoted free radical generation, upregulated poly (ADP-ribose) polymerase expression, activated caspase-3, as well as promoted cell apoptosis. Importantly, apoptosis could be inhibited by the free radical scavengers glutathione (GSH) and N-acetyl-L-cysteine (NAC). The results suggest that SO2/AAT1/AAT2 pathway might protect against the development of OA-induced ALI by inhibiting oxidative stress.

Regulatory effects of hydrogen sulfide on alveolar epithelial cell endoplasmic reticulum stress in rats with acute lung injury

The present study was undertaken to examine the regulatory effect of hydrogen sulfide (H2S) on endoplasmic reticulum stress in alveolar epithelial cells of rats with acute lung injury (ALI) induced by oleic acid (OA). Seventy-two male Sprague Dawley (SD) rats were divided into control group, oleic acid-induced ALI group (OA group), oleic acid-induced ALI with sodium hydrosulfide (NaHS) pretreatment group (OA+NaHS group), and sodium hydrosulfide treatment group (NaHS group). Rats of each group were further subdivided into 3 subgroups. Index of quantitative assessment of histological lung injury (IQA), wet/dry weight ratio (W/D) and H2S level of lung tissues were measured. The expressions of endoplasmic reticulum stress markers including glucose-regulated protein 78 (GRP78) and α-subunit of eukaryotic translation initiation factor-2 (elF2α) in lung tissues were measured by immunohistochemical staining and Western blotting. The IQA score and W/D ratio of lung tissues at the three time points significantly increased in rats injected with OA, but significantly decreased in other rats injected with OA and NaHS. The level of H2S in lung tissue at the three time points significantly decreased in rats injected with OA, but significantly increased in other rats injected with both OA and NaHS. GRP78 and elF2α decreased in rats injected with OA, but increased in other rats injected with both OA and NaHS, especially at 4-hour and 6-hour time points. The results suggested that H2S could promote alveolar epithelial cell endoplasmic reticulum stress in rats with ALI.

Xuebijing injection improves the respiratory function in rabbits with oleic acid-induced acute lung injury by inhibiting IL-6 expression and promoting IL-10 expression at the protein and mRNA levels.

Xuebijing injection is a complex herbal medicine, and clinical and experimental studies have shown that it has a significant effect on acute respiratory distress syndrome and multiple organ dysfunction syndrome. However, the majority of studies regarding Xuebijing injection have focused on serum inflammatory factors, and few studies have been carried out from the perspective of the protein and mRNA expression of inflammatory cytokines. In this study, 60 healthy rabbits of mixed gender were randomly assigned to a normal control group (CG), oleic acid group (model group; MG) and oleic acid + Xuebijing injection group (treatment group; TG). Rabbits of the CG were treated with normal saline through the ear vein, rabbits of the MG were injected with oleic acid (0.4 ml/kg) and rabbits of the TG received 0.4 ml/kg oleic acid + 10 ml/kg Xuebijing injection. Blood samples were collected from the common carotid artery of all rabbits of all groups 1 h after the ear vein was injected with the corresponding reagent, and was used to measure the arterial partial pressure of oxygen (PaO2) and of carbon dioxide (PaCO2). The activity of myeloperoxidase (MPO) was tested, and the protein and mRNA expression levels of interleukin (IL)-6 and IL-10 were determined. Rabbits of the MG exhibited evident respiratory dysfunction (PaO2 and PaCO2 were low), histopathological lung damage and overactive inflammatory responses (the expression of the proinflammatory cytokine IL-6 and the anti-inflammatory cytokine IL-10 was increased at the protein and mRNA levels). Following the administration of the Xuebijing injection, the inflammatory response of the rabbits was significantly reduced. Xuebijing injection raised PaO2 and PaCO2, weakened the activity of MPO in the lung tissue, downregulated the expression of the proinflammatory cytokine IL-6 and further increased the expression of the anti-inflammatory cytokine IL-10. These results demonstrated that Xuebijing injection improved the respiratory function of rabbits with acute oleic acid-induced lung injury by inhibiting IL-6 expression and promoting IL-10 expression.

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

MicroRNAs mediate oleic acid-induced acute lung injury in rats using an alternative injury mechanism.

Intravenous (IV) infusion of oleic acid (OA) distributes OA microemboli in the pulmonary capillaries, which results in severe vascular congestion, hemorrhage vascular congestion, interstitial edema, intravascular coagulation and bleeding. The immune response to acute lung injury (ALI) is known to be associated with rapid and widespread changes in microRNA (miRNA) expression in the lung. The present study of a model of rat lung injury aimed to investigate how the lung miRNA profile changes to mediate ALI. For the induction of ALI, OA (200µl/kg) suspended in 20% ethyl alcohol was injected through the tail vein for 20min. Lung tissue samples were acquired at 3, 6 and 24h, and miRNA microarray and quantitative polymerase chain reaction were performed using these samples. The activation of phosphatase and tensin homolog (PTEN), protein kinase B (Akt), extracellular signal-regulated kinases (ERK) and c-Jun N-terminal kinases (JNK) were analyzed by western blot analysis. There were 75 miRNAs that demonstrated >1.5‑fold changes in expression levels. miR-101a was highly upregulated at 3h. miR-21 was upregulated in the OA group throughout the 24h following OA challenge. miR-1 was the most downregulated miRNA at 24h. In order to examine the expression levels of PTEN and Akt as targets of miR-21, western blot analysis was performed. At 3h, the levels of PTEN were attenuated in the OA group as compared with those in the control group; however, p-Akt/Akt levels were increased at 3h for the OA group. PTEN and p-Akt/Akt were significantly higher in the OA group at 3h and were rapidly decreased at 6h. The immunohistochemical stain of α-smooth muscle actin in the bronchial and alveolar wall increased 24h after OA‑induced ALI. These results indicated that the profile of miRNAs dynamically changed throughout the OA-induced ALI process, and mitogen-activated protein kinase activation, PTEN/Akt pathway alteration and smooth muscle actin activation were observed in this ALI model.

Leptin Attenuates Lipopolysaccharide or Oleic Acid-Induced Acute Lung Injury in Mice

Leptin is reported to be involved in acute lung injury (ALI). However, the role and underlying mechanisms of leptin in ALI remain unclear. The aim of this study was to determine whether leptin deficiency promoted the development of ALI. LPS or oleic acid (OA) were administered to wild-type and leptin deficient (ob/ob) mice to induce ALI. Leptin level, survival rate, and lung injury were examined. Results showed that leptin levels were predominantly increased in the lung, but also in the heart, liver, kidney, and adipose tissue after LPS adminiatration. Compared with wild-type mice, LPS- or OA-induced lung injury was worse and the survival rate was lower in ob/ob mice. Moreover, leptin deficiency promoted the release of proinflammatory cytokines. Exogenous administration of leptin reduced lethality in ob/ob mice and ameliorated lung injury partly through inhibiting the activation of NF-κB, p38, and ERK pathways. These results indicated that leptin deficiency contributed to the development of lung injury by enhancing inflammatory response, and a high level of leptin improved survival and protected against ALI.