Relativity of beta adrenoceptor changes between polymorphonuclear leukocytes and lung tissue in acute lung injury rats

AIM：To observe changes of beta-adrenoceptor (β-AR) and its relativity to polymorphonulear leukocytes (PMN) and acute lung injury (ALI) in rats. METHODS:ALI modle in rat was established by intravonous injection of E. Coli endotoxin (ET). β-AR was measured by radioligand binding assay with -dihydroalprenlol.RESULTS:(1)Maxmal capacity of β-AR (Bmax) in both lung tissue and PMN decreased significantly at the lst, 4th and 6th hours after injection of ET. (2)No relativity was found between β-AR Bmax changes of lung tissue and β-AR Bmax changes of PMN. CONCLUSIONS:(1) Decrease of density of β-AR in lung tissue and PMN may played a role in the development of ALI. (2) The β-AR of PMN in circular blood can not be used as a relative index of β-AR changes of lung tissue in rats with ALI.     

会讯

AIM:To investigate the pulmonary expresson of macrophage migration inhibitory factor(MIF) in acute lung injury (ALI) rats induced by intravenous injection of oleic acid and its correlation with blood gas change, pulmonary weight index (PWI) and pulmonary pathological injuries.METHODS: ALI rats model were made by injecting oleic acid as the oleic acid group while rats injection with saline solution as control. After injecting oleic acid or saline for six hours, the PaO₂ and PaCO₂ of the left heart and pulmonary weight index were measured. At the same time, by using a microwave-base double immunohistochemistry labeling, the number of MIF^＋, ED₁⁺ (anti-CD68 antibody), ED₁⁺/MIF^＋cell in pulmonary tissue of different groups and their correlation with blood gas and pulmonary weight index were examined. RESULTS: The blood gas parameters of the oleic acid group were far worse than that of the control group (P＜0.01). The PWI of the oleic acid group was significantly higher than that of the control group (P＜0.01). There was marked upregulation of MIF expression on injured lung tissue. The number of cell expressed MIF^＋ , ED₁⁺ and MIF with ED₁ showed a strong positive correlation with PaO₂, PWI and histological changes. CONCLUSION: MIF may play a pivotal role in mediation of progressive lung injuries induced by intravenous oleic acid injection. In addition, the number of cells expressed MIF, especially macrophage, may reflect the severity of lung injury.     

Effect of interleukin-10 on attenuating endotoxin-induced acute lung injury

AIM: To study the role of polymorphonuclear neutrophile(PMN) in lipopolysaccharide (LPS)- induced acute lung injury (ALI) and the protective effect of interleukin -10(IL-10) on ALI. METHODS: LPS alone (100μg) or LPS+ IL-10 (l ug) was instilled intratracheally into rats. PMN numbers, protein content and malondialdehyde (MDA) content in bronchoalveolar lavage fluid (BALF) were measured. Histological change of lung was also observed. RESULTS: LPS increased significantly PMN numbers, protein content and MDA content in BALF. Histological finding shows PMN accumulation in lung. IL - 10+LPS reduced remarkably PMN numbers ,pro- tein content and MDA content in BALF than those caused by LPS. PMN decreasing was also identified by light microscopy. CONCLUSION: LPS instilled intratracheally causes PMN accumulation in lung and ALI, while IL - 10 could alleviate ALI through reducing PMN accumulation.     

Effect of pulmonary vascular endothelial cells on the development of acute lung injury in rats

AIM: Effect of endothelial cell on the development of acute lung injury and the prevention of dexamethasone in acute lung injury were observed.METHODS:Rats were divided into three groups:1.Control group.2.LPS group:Venous injection with LPS(5mg/kg body weight),execute respectively at 1 h,2 h,6 h and 24 h after LPS injection. 3.dexamethasone group:intraperitoneal injection with dexamethasone ,1 h before LPS injection,execute after 2 hours after LPS injection.RESULTS: Serum NO,TNF-α levels,lung iNOS activity and lung ICAM-1mRNA expression were increased( P <0.05, P <0.01, vs control group),but serum ACE was decreased( P <0.01).Dexamethasone could improve all the changes above mentioned.CONCLUSION:Endothelial cell played a vital role in the development of acute lung injury and dexamethasone could prevent acute lung injury.     

Role of macrophage and intercellular adhesion molecule-1 in the pathogenesis of oleic-acid-induced rat acute lung injury

AIM: To investigate the role of infiltration of macrophages and expression of intracellular adhesion molecule-1 in the pathogenesis of oleic-acid-induced acute lung injury rats. METHODS:The rats were subjected to injection of oleic acid (oleic acid group) or saline solution (control). After injecting oleic acid or saline for 4 hours, the PaO₂ of the left heart, lung permeability index(LPI), the number of macrophage and the levels of soluble intercellular molecule-1 (sICAM-1) in the bronchial alveolar lavage fluid (BALF) were measured. The levels of expression of ICAM-1 mRNA were evaluated by in situ hybridization and the degree of macrophage infiltration and the expression of ICAM-1 were evaluated by double staining immunocytochemistry. RESULTS:The PaO₂ of the oleic acid group was significantly lower than that of the control group (P＜0.01) and the LPI of the oleic acid group was significantly higher than that of the control group (P＜0.01). The cell number of macrophage and sICAM-1 level were significantly higher in the oleic acid group than those of the control group (P＜0.01). There were marked upregulation of ICAM-1 mRNA expression in injuried lung tissue compared with the normal lung tissue. Furthermore, the infiltrated number of macrophage and the level of ICAM-1 expression showed strong positive correlation with the lung injury parameters, PaO₂ and LPI.CONCLUSION:The infiltration of macrophage may play a pivotal role in the pathogenesis of progressive lung injuries induced by intravenous oleic acid injection,ICAM-1 may mediate the infiltrat ion and adhesion of macrophage in the injuried lung t issue and contribute to the development of acute lung injury.     

Effects of aminoguanidine on endotoxin-induced acute lung injury in rabbits

AIM: To observe the effect of aminoguanidine (AG) on hemodynamics and lung capillary permeability in acute lung injury (ALI) in rabbits. METHODS:24 rabbits were equally divided into four groups: saline group, endotoxin group, AG group and AG plus endotoxin group. In AG plus endotoxin group, endotoxin was injected to animals to make an ALI model, 25mg/kg AG was injected following that and let this sustain 3 hours. Meanwhile, mean arterial pressure (MAP), mean pulmonary arterial pressures (MPAP) and blood gas analyses were observed during this period. At the end of the experiment, broncho-alveolus lavage was performed, pathologic samples were treated routinely and lung wet weight/dry weight ratio was calculated. RESULTS:After endotoxin injection, MAP and arterial oxygen pressure (PaO₂) decreased, and MPAP increased significantly. The injection of AG had little effect on MAP, but AG could markedly decrease MPAP and increase PaO₂. Cell count in broncho-alveolus lavage fluid (BALF) was less in AG plus endotoxin group than in endotoxin group. Although AG did not affect total protein in BALF, low molecular weight proteins decreased in AG plus endotoxin group by the assay of electrophoresis. Tissue wet weight/dry weight ratio also decreased in this group. Pathologic study showed that there were fewer inflammatory cells and less lung edema in AG plus endotoxin group. CONCLUSION:AG could improve hemodynamics status and attenuate acute lung injury induced by endotoxin in rabbits.     

Role of stress in the lung injury caused by acute hemorrhagic necrotizing pancreatitis in rats

AIM:To study the relation ship between stress and lung injury caused by acute hemorrhagic necrotizing pancreatitis(AHNP) through AHNP model.METHODS:The AHNP model was made by using 5% sodium taurocholate retrograded injection into biliopancreatic duct in SD rats. Those rats were divided into three groups randomly, from A to C, the A group undertook sham operations, the B group was made into AHNP model, and the C group was given Metyrapone. The level of corticosteroid, CRP and amylase in serum had been observed. The lung and pancreas histological examinations were also performed.RESULTS: In C group, the level of corticosteroid, CRP and amylase were much lower than those in B group. The grade of lung and pancreas injury were also lower than those in B group(P＜0.05).CONCLUSION:Stress lays an important role in the lung injury caused by AHNP. Using anti-stress drugs can inhibit this course and meliorate the lung injury.     

Effects of quercetin on apoptosis of alveolar polymorphonuclear neutrophils in severe acute pancreatitis rats with lung injury

AIM：To explore the effects of quercetin (Que) on the apoptosis of alveolar polymorphonuclear neutrophils (PMN) isolated from severe acute pancreatitis (SAP) rats with lung injury. METHODS：Forty-eight SD rats were randomly divided into 4 groups：sham group, SAP group, low-dose (50 mg/kg) Que group and high-dose (100 mg/kg) Que group. SAP was induced by retrograde administration of 5% sodium taurocholate into the biliary pancreatic duct. The SAP rats in Que groups were given quercetin, while the rats in sham group and SAP group received an infusion of physiological saline. Alveolar PMN were harvested by the collection of bronchoalveolar lavage fluid. The cell morphological changes were observed under fluorescent microscope. The cell apoptotic index was analyzed by flow cytometry. The protein levels of Bax and Bcl-2 were examined by Western blotting. Caspase-3 activity was measured by fluorescence spectrophotometry. RESULTS：Cell shrinkage and condensation of chromosomes were observed in alveolar PMN from SAP rats. Compared with sham group, the apoptotic index of alveolar PMN reduced in SAP group. The protein expression of Bax was significantly reduced, that of Bcl-2 was significantly enhanced, and caspase-3 activity was attenuated. After Que pretreatment, the apoptotic index of alveolar PMN increased, the protein expression of Bax was significantly enhanced, that of Bcl-2 was significantly reduced, and caspase-3 activity increased. The effects of Que presented a concentration-dependent manner, indicating that Que alleviated SAP-induced lung injury. CONCLUSION：The apoptosis of alveoar PMN is delayed in SAP rats. Quercetin induces apoptosis of alveolar PMN by up-regulating the expression of Bax and down-regulating the expression of Bcl-2.     

The protective effect of anti-macrophage migration inhibitory factor monoclonal antibody on oleic-acid-induced acute lung injury

AIM: To investigate the protective effect of anti-macrophage migration factor monoclonal antibody (anti-MIF MAb) on oleic-acid-induced acute lung injury (ALI) rats and its influence on the expression level of MIF and intercellular adhesion molecule-1(ICAM-1). METHODS: The rats were subjected to injection of oleic acid (oleic acid group) or saline solution (control group). One hours before administration of oleic acid, the rats were intraperitoneally injected with anti-MIF antibody (5 mg/kg) as the treatment group. After injecting oleic acid or saline for 4 hours, the PaO₂, lung permeability index (LPI), the number of macrophage and the level of soluble ICAM-1 (sICAM-1) in the bronchial alveolar lavage fluid (BALF) were measured. The expression level of MIF mRNA and ICAM-1 mRNA in the lung were detected by in situ hybridization, and the degree of macrophage infiltration and the expression of MIF were evaluated by double staining immunocytochemistry. RESULTS: The PaO₂ of the oleic acid group was far lower than those of the control and treatment group (P<0.01). The LPI of the oleic acid group was significantly higher than those of the control and treatment group (P<0.01). The sICAM-1 level in BALF were significantly higher than those of the control and treatment groups (P<0.01). There were marked up-regulation of MIF mRNA and ICAM-1 mRNA expression in ALI lung compared with the normal lung tissue. After pretreatment with anti-MIF antibody, the MIF expression was down-regulation in association with a marked reduction of macrophage infiltration. However, pretreatment with anti-MIF antibody did not interfere the expression level of ICAM-1. CONCLUSION: MIF and ICAM-1 may mediate the infiltration and adhesion of macrophage in injuried lung tissue, which play a pivotal role in the pathogenesis of progressive lung injuries induced by intravenous oleic acid. Pretreatment with anti-MIF antibody showed lung protective effect by blockage of MIF expression in association with reduction of macrophage infiltration and improvement in histological damage.     

Effect of intestinal endotoxemia on hepatic energy metabolism in acute liver failure

AIM:To study the effect of intestinal endotoxemia(IETM) on hepatic energy metabolism in acute liver failure. METHODS:Intoxication by thioacetamide (TAA) was used to establish rat model of acute liver injury.Ketone body(acetoacetate and β-hydroxybutyrate) in arterial blood and ATP content of hepatocellular mitochondria were determined by using enzymatic fluorimetric micromethod.Colectomy was adopted in observing the changes in plasma endotoxin content and serum alanine aminotransferase (ALT) activity. RESULTS:In the TAA group,plasma endotoxin content and serum ALT activity were all significantly higher than those in the control group(P＜0.01),arterial ketone body ratio of acetoacetate to β-hydroxybutyrate (AKBR) decreased below 0.4,total ketone body in arterial blood was significantly lower than that in the control group(P＜0.01).In the TAA+colectomy group,there was no endotoxemia to be found,ATP content of hepatocellular mitochondria was significantly higher than that in the TAA group(P＜0.01), though serum ALT activity was higher than that in the control group(P＜0.05),but significantly lower than that in the TAA group(P＜0.01). CONCLUSION:IETM played a key role in the occurrence of acute liver failure,hepatic dysfunction might be caused by IETM through damaging hepatic energy metabolism.     

The effect of partial liquid ventilation on the ultrastructure of pulmonary surfactant system in endotoxin-induced acute lung injury in rats

AIM: To study the effect of partial liquid ventilation on the ultrastructure of pulmonary surfactant(PS) system in endotoxin-induced acute lung injury. METHODS: The effect of partial liquid ventilation on the ultrastructure of PS system in endotoxin-induced acute lung injury was observed with electronmicroscope histochemistry. RESULTS: There was ultrastructure impairment of PS system in endotoxin-induced acute lung injury, the pulmonary surfactant layer was discontinuous, lamellar bodies and plasmosomes in type Ⅱ pneumonocytes vacuolated, and a few of them were even necrotized and disrupted into the alveolar space. The pulmonary surfactant layer was still continuous, the vacuolation of lamellar bodies and plasmosomes in type Ⅱ pneumonocytes was little with partial liquid ventilation. CONCLUSION: Partial liquid ventilation can lessen the impairment of PS system in endotoxin-induced acute lung injury in rats.     

Effects of IL-6 and IL-1α on the peripheral blood polymorphonuclear neutrophil apoptosis postburn in rats

AIM:To study the effects of IL-6 and IL-1α on the blood polymorphonuclear-neutrophils(PMN) apoptosis postburn.METHODS:Wistar rats inflicted by 30% total body surface area (TBSA) Ⅲ degree scalding were employed as the model. PMN were isolated by density gradient centrifugation using Percoll-hypaque and labeled with TdT-mediated and dUTP nick end labeling (TUNEL) and analyzed by flow cytometric analysis. The intracellular caspase-3 activation and the serum levels of IL-6 and IL-1α were analyzed by fluorometric immunosorbent enzyme assay and enzyme-linked immunosorbent assay, respectively.RESULTS:The serum IL-6 levels (μg/L) in groups of 3, 6, 12, 24 and 48 h postburn (9.14±1.16, 12.49±1.14, 3.01±0.75, 1.41±0.28 and 1.56±0.43 in turn) and IL-1α (ng/L) in groups of 3, 6, 12 h postburn (90.08±8.39, 320.93±14.48 and 47.84±5.19) were much higher than IL-6 (0.24±0.07) and IL-1α (27.65±4.86) in control group (P＜0.05), respectively. The relative proportions of apoptotic PMN(%) in groups postburn were 9.89±2.00, 4.98±1.35, 1.31±0.72, 2.49±1.87 and 6.88±1.13 in turn, which were obviously less than 13.66 ± 3.88 in the control group. The results of intracellular caspase-3 activation in PMN were observed to be consistent with the results of apoptotic PMN analysis in experimental groups.CONCLUSION:IL-6 and IL-1α are the important factors to induce PMN apoptosis delay that occurred obviously postburn. And decrease in the activity of intracellular caspase-3 of PMN may be involved in their mechanisms.     

Expression of intercellular adhesion molecule in lung tissues of experimental acute lung injury and the effect of rhubarb

AIM:To approach the relationship between the expression of intercellular adhesion (ICAM-1 mRNA) and acute lung injury (ALI) as well as the mechanisms of rhubarb in the prevention and treatment of the lung injury. METHODS:ALI animal model was performed by Lipopolysaccharide (LPS). The rats were divided into 4 groups: LPS group, control group, rhubarb+LPS group and dexamethasone+LPS group. Histopathological examination and biological markers were measured for the lung specimens. Molecular hybridization method was used to determine the expression of ICAM-1 mRNA. RESULTS:The ICAM-1 mRNA expression in the lung tissues of LPS group significantly increased compared with control group (P＜0.01), rhubarb and dexamethasone had the action of decreasing the ICAM-1 mRNA expression (P＜0.05, P＜0.01); pathologic changes and the biological markers of ALI significantly decreased or ameliorated. CONCLUSION:The increase in the expression of ICAM-1 mRNA in the lung tissues of ALI is involved in the formation of ALI. Rhubarb and dexamethasone can ameliorate the lung damage, mechanism of which may be related to the inhibition of ICAM-1 mRNA expression.     

Effects of silymarin on LPS-induced acute lung injury in rats

AIM:To investigate the effects of silymarin on lipopolysaccharide (LPS)-induced acute lung injury in rats and its possible molecular mechanisms. METHODS:Fifty-eight male SD rats, weighting 230-250 g, were divided into four groups randomly: normal control (n=12); acute lung injury group (n=15), receiving intravenous LPS (O55∶〖KG-*2〗B5, 5 mg/kg); silymarin alone group (50 mg/kg, n=15); intervention group (n=16, receiving silymarin 50 mg/kg and LPS 5 mg/kg). The specimens were collected 6 hours later. The following changes, including blood gas analysis, the lung wet/dry weight ratio, the pulmonary vascular permeability, histological manifestations, lung tissue myeloperoxidase activity, the levels of TNF-α, IL-1β, MCP-1 and SOD, GSH-Px as well as malonaldehyde and conjugated diene in plasma and lung tissue, were observed. RESULTS:Compared with control group, the lungs of the rats in LPS treatment group showed significant hyperemia and spotted hemorrhage. The inflammatory granulocyte infiltrating, diffused alveolar septum thickening and spotted hemorrhage were observed in pathological examinations. The lung wet/dry weight ratio and Evans blue content (per gram) increased significantly after LPS treatment. The myeloperoxidase activity in plasma and lung tissue, the levels of TNF-α, IL-1β, MCP-1 and SOD, GSH-Px as well as malonaldehyde and conjugated diene were increased significantly in LPS treatment group. However, in intervention groups, all the above-mentioned measurements were reversed significantly by silymarin treatment compared with LPS treatment group. CONCLUSION:Silymarin may decrease inflammatory reaction and oxidative stress, and further decrease lung damage induced by LPS in rats, all indicating protection of silymarin against acute lung injury.     

Pre-treatment with melatonin inhibits oleic acid-induced acute lung injury in rats

AIM: To assess the protective role of melatonin (MEL) in a rat model of oleic-induced acute lung injury.METHODS: Twenty-four rats were randomly allocated to three groups as follows: saline(NS) injection group, oleic acid(OA) injection group and MEL plus OA injection group, the lavage protein, lung wet-to-dry weight ratio, malondialdehyde(MDA) content, superoxide dismutase(SOD) activity and lung histopathology were examined. RESULTS: (1) Injection 0.15 mL/kg of OA led to a severe acute lung injury(ALI), characterized by significantly increasing in lavage protein, lung coefficient (P<0.01), and by histopathological alterations which presented hemorrhage, edema, thickened alveolar septum and the existence of inflammatory cells in alveolar spaces; (2) Infusion of MEL (20 mg/kg, intraperitoneally for 60 min before the oleic acid) markedly alleviated above-mentioned symptom induced by OA, consistent with decrease of MDA level (P<0.01) and the increase of SOD activty (P<0.01). CONCLUSION: Pre-treatment with MEL can attenuate the OA-induced ALI in rats via cleaning and preventing the formation of free radicals and further lessening the increase of alveolocapillary membrane permeability, these data suggest that MEL may be effective in the prevention of ALI.     

Effect of nitric oxide and peroxynitrite on lung injury induced by ischemia-reperfusion of hind limbs in rats

AIM:To observe the changes in nitric oxide(NO) and peroxynitrite anion (ONOO^- ) in the injuried lung following the ischemia-reperfusion of hind limbs and evaluate the contribution of NO and ONOO^- to tissue injury.METHODS:A model of hind limbs ischemia was made by clamping infrarenal aorta with a microvascular clip and lung injury occurring after reperfusion.Lung t issue was obtained from the animals received sham operation(group 1),4 hours ischemia without reperfusion(group2),1 hour reperfusion following 4 hours ischemia(group3)and 4 hours reperfusion fol owing 4 hours ischemia(group4).The contents of MDA,NO₂^-/NO₃^- and the activities of SOD in the lung were examined.Immunohistochemical echnique was used to determine the immunoreactivity to iNOS and nitrotyrosine(NT)-a specific "footprint" of peroxynitrite.RESULTS:Compared with group1 and group2,the contents of MDA and NO₂^-/NO₃^- increased significantly (P<0.05) and the activities of SOD decreased markedly(P＜0.05) in group3 and group4.Immunohistochemical examination demonstrated intense staining for iNOS and NT throughout the lung in group3 and group4.CONCLUSION:NO and ONOO^- are involved in oxidant-mediated lung injury following reperfusion of ischemic hind limbs.     

Effects of NG-nitro-L-arginine on LPS-induced lung injury in rats

AIM: To investigate the effects of nitric oxide (NO) and NO synthase (NOS) inhibitor N^G-nitro-L arginine (L-NA) on LPS induced-lung injury in rats. METHODS: Forty healthy male SD rats, weighing 300±20 g, were used. The animals were anesthetized with 20% urethane 1 g·kg^-1. Common carotid artery (CAA) and jugular vein were exposed through a median incision in the neck. Mean arterial pressure (MAP) was measured through a pressure transducer connected with intubation of CAA. The animals were randomly divided into five groups: group 1: control; group 2: LPS (5 mg·kg^-1, iv); group 3: high dose L-NA (20 mg·kg^-1 intraperitoneal injection, ip); gropu 4: middle dose L-NA (10 mg·kg^-1, ip); group 5: low dose L-NA (5 mg·kg^-1, ip). Group1 : 0.9% saline solution was given and the animals were killed 6 h after the saline solution. Gruop 2: saline solution was given 3 h after LPS and the animals were killed 3 h after administration. Group 3, 4 and 5: L-NA was given 3 h after LPS iv and the animals were killed 3 h after administration, respectively. The pulmonary was removed immediately. The pulmonary coefficient and water content in pulmonary tissue were calculated (%). The NO₂^-/NO₃^- content in plasma, MDA content and NOS, SOD activity in the pulmonary tissue were measured. RESULTS: L-NA significantly decreased pulmonary coefficient and water content in pulmonary tissue and ameliorated LPS induced lung injury. The effect in high dose group was better than that in low dose group. L-NA significantly decreased NO₂^-/NO₃^- content in plasm, decreased MDA content and inhibited NOS activity and enhanced SOD activity in the pulmonary tissue. CONCLUSION: It may be concluded that L-NA has a beneficial effect on lung injury induced by LPS.     

Effect of DADLE on lung injury in rats with acute global cerebral ischemia-reperfusion

AIM：To observe the effects of δ opioid receptor agonist DADLE on acute lung injury (ALI) induced by acute global cerebral ischemia-reperfusion in rats. METHODS：SD rats (n=30) were randomly divided into sham group, model (I/R) group and DADLE treatment group. Global cerebral ischemia-reperfusion model was established by a modified 2-vessel occlusion plus hypotension. DADLE (5 mg/kg) treatment was performed via the left jugular injection before reperfusion. After 120-min reperfusion, the pathological changes of the lung tissues were observed under light microscope and electronic microscope. The activity of superoxide dismutase (SOD) and malondialdehyde (MDA) level were detected. The partial pressure of arterial oxygen (PaO2) was also measured. RESULTS：In I/R group, widened alveolar septum, capillary dilatation and congestion, endovascular and perivascular cells in the lung with neutrophil infiltration, and significantly reduced type II epithelial cell surface microvilli, alveolar lumen cavity and trachea with serous exudate were observed. SOD activity decreased, but the MDA level increased. Compared with I/R group, the SOD activity increased and MDA level decreased in DADLE treatment group, with significantly reduced lung congestion, the degree of lung injury, and the infiltration of neutrophils. Compared with I/R group, the PaO2 and oxygenation index in DADLE treatment group were increased. CONCLUSION：Various degrees of pulmonary injury were observed in acute global cerebral ischemia reperfusion model. DADLE might have a protective effect on lung tissues of ALI in rats.