Objective To investigate the pathogenesis of acute lung injury in rats induced by intra-peritoneally injection of perforative peritonitis ascitic fluids（PPAF） and the role of L-arginine （L-Arg） in acute lung injury in this model. Methods Perforative peritonitis （PP） models were established in 60 rats and PPAF were collected. Forty-eight rats were randomly divided equally into NS group，PPAF group, and L-Arg group. Rats were randomly subjected to death at 7 h and 12 h. Peripheral blood WBC were counted，levels of NO and malondialdehyde （MDA） in serum were examined. Lung injury score and wet/dry ratio were evaluated， and level of myeloperoxidase （MPO） in lung tissues and lung cell apoptosis were tested. Results WBC count of peripheral blood, levels of NO and MDA in serum， level of MPO in lung tissue, lung injury score， wet/dry ratio， and lung cell apoptosis rate in PPAF group were significantly higher than that in NS group at each time point（P＜0.01）. Level of NO in serum in L-Arg group was higher than that in PPAF group （P＜0.01）， but lower level of MDA in serum， lower level of MPO in lung tissue and lung injury score，lower wet/dry ratio， and lung cell apoptosis rate were observed in L-Arg group（P＜0.05）. In PPAF group and L-Arg group， level of NO in serum， wet/dry ratio, and lung cell apoptosis rate were higher at 12 h than that at 7 h（P=0.000）. Serum NO level was in negative correlation with serum MDA level （r=-0.257，P=0.021）， MPO level in lung tissue（r=-0.444， P=0.011），and lung cell apoptosis（r=-0.351， P =0.010） in PPAF group and L-Arg group， but serum MDA level was in positive correlation with cell apoptosis（r=0.969， P＜0.001） in each group. Conclusions Acute lung injury rats model can be established by intra-peritoneally injection of PPAF. Enhanced oxidizing reaction and cell apoptosis take part in the occurrence of acute lung injury. L-Arg plays a protective role in acute lung injury.
With the growth of offshore activities, the incidence rates of seawater drowning (SWD) induced acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) increase significantly higher than before. Pulmonary interstitial edema, alveolar septum fracture, red blood cells, and inflammatory cells infiltration can be seen under light microscope in the pathologic changes of lungs. The major clinical manifestations are continual hyoxemia and acidosis, which lead to a severe condition, a high death rate, and a poor treatment effect. Bone marrow mesenchymal stem cells are capable of self-renewal, multilineage differentiation and injured lung-homing, which are induced to differentiate into alveolar epithelial cells and pulmonary vascular endothelial cells for tissues repairing. This may be a new way to treat SWD-ALI and SW-ARDS.
Objective To construct the mouse NF-κB P65 subunit expression plasmid, and identify its biological activity. Methods NF-κB P65 siRNA retrovirus expression vectors were reconstructed by molecular clone technology. Recombinant vectors were transfected into 293E package cells and virus suspension was collected. RT-PCR was used to detect the expression level of NF-κB P65 mRNA and TNF-α mRNA at different time-point of LPS stimulation. Western blot was performed to analyze the protein level of NF-κB P65. ELISA was applied to detect the expression level of TNF-α released by LPS-stimulated J774A.1. Results NF-κB P65 siRNA retrovirus expression vectors of mouse were successfully constructed. From2 hours after the stimulation of LPS, the expression level of NF-κB P65 mRNA of the siRNA group was obviously lower than the scramble control group ( 0.91 ±0.03 vs. 1.02 ±0.02, Plt;0.01) . At24,36, 48 and 72 hours after the LPS stimulation, the expression level of NF-κB P65 protein of the siRNA group was significantly decreased compared with the scramble control group ( 0.97 ±0.02 vs. 1.01 ±0.01, 0.94 ± 0.01 vs. 1.02 ±0. 01,0.94 ±0.02 vs. 1.02 ±0.01, 0.93 ±0.01 vs. 1.00 ±0.02, Plt;0. 05) . At 2, 6, 12, 24 hours after the LPS stimulation, both the expression level of TNF-α mRNA and the content of TNF-α in the culture medium supernatant of the siRNA group were lower than the scramble control group ( Plt;0. 01) . Conclusions The construction of NF-κB P65 siRNA retrovirus expression vectors is feasible. Inflammation factors in mouse monocyte-macrophages are significantly inhibited after NF-κB expression is depressed by RNA interference technology, which may be applied to prevent and treat excessive inflammatory reaction in acute lung injury.
ObjectiveTo investigate the role and mechanism of P-selectin glycoprotein ligand-1 (PSGL-1) in hydrochloric acid-induced acute lung injury (ALI) in mice.MethodsWild-type mice (WT) and PSGL-1 knockout mice (PSGL-1 -/-) were randomly subjected to normal saline (NS) or hydrochloric acid (HCl) challenged group. The mice were intratracheally instilled with NS or HCl (1 μl/g weight) into the left lung with a catheter. After 2 hours, respiratory function index enhanced pause (Penh), PaO2 and PaO2 were analyzed. The wet to dry weight ratio (W/D) of the left lung and total protein concentration in bronchoalveolar lavage fluid (BALF) were measured. The number of leukocytes in BALF was counted too. Targeted lung tissue was processed for further HE or immunohistochemistry staining. Meanwhile, the expressions of interleukin-6 (IL-6), IL-1β, nuclear factor-κB (NF-κB), IκBa and p-IκBa in lung tissue were measured.ResultsThe Penh (4.77±1.22 vs. 5.80±0.84) and PaCO2 [(63.7±3.9) mm Hg vs. (74.4±7.4) mm Hg] in the PSGL-1 knockout mice were significantly lower than those in the WT mice after HCl stimulation (P<0.05), while the PaO2 was higher than that in the WT mice [(81.0±7.1) mm Hg vs. (62.0±8.9) mm Hg, P<0.05)]. The lung W/D ratio (4.86±0.15 vs. 5.22±0.20), protein concentration [(3.71±0.64) μg/μl vs. (4.74±0.98) μg/μl] and total leukocyte count [(13.00±2.18) ×107/L vs. (49.42±3.35) ×107/L] in BALF were significantly lower in the PSGL-1 knockout mice challenged with HCl than those in the WT mice (P<0.05). Besides, the protein expressions of IL-6, IL-1β, p65 and p-IκBa in the PSGL-1 knockout mice were lower than those in the WT mice after HCl instillation, while the IκBa expression was higher than that in the WT mice (P<0.05). More numbers of neutrophils and macrophages were found in the lung of the WT mice than the PSGL-1 knockout mice challenged with HCl. However, the differences of above values between the WT mice and the PSGL-1 knockout mice instilled with NS were not found, all of which were significantly lower than the correspongding HCl group except for IκBa (P<0.05).ConclusionPSGL-1 may play important roles in the development of HCl-induced ALI via the NF-κB signaling pathway and inflammation.
Objective To evaluate the efficiency and associated factors of noninvasive positive pressure ventilation( NPPV) in the treatment of acute lung injury( ALI) and acute respiratory distress syndrome( ARDS) .Methods Twenty-eight patients who fulfilled the criteria for ALI/ARDS were enrolled in the study. The patients were randomized to receive either noninvasive positive pressure ventilation( NPPV group) or oxygen therapy through a Venturi mask( control group) . All patients were closely observed and evaluated during observation period in order to determine if the patients meet the preset intubation criteria and the associated risk factors. Results The success rate in avoiding intubation in the NPPV group was 66. 7%( 10/15) , which was significantly lower than that in the control group ( 33. 3% vs. 86. 4% , P = 0. 009) . However, there was no significant difference in the mortality between two groups( 7. 7% vs.27. 3% , P =0. 300) . The incidence rates of pulmonary bacteria infection and multiple organ damage were significantly lower in the NPPV success subgroup as compared with the NPPV failure group( 2 /10 vs. 4/5, P =0. 01;1 /10 vs. 3/5, P = 0. 03) . Correlation analysis showed that failure of NPPV was significantly associated with pulmonary bacterial infection and multiple organ damage( r=0. 58, P lt;0. 05; r =0. 53, P lt;0. 05) . Logistic stepwise regression analysis showed that pulmonary bacterial infection was an independent risk factor associated with failure of NPPV( r2 =0. 33, P =0. 024) . In the success subgroup, respiratory rate significantly decreased( 29 ±4 breaths /min vs. 33 ±5 breaths /min, P lt; 0. 05) and PaO2 /FiO2 significantly increased ( 191 ±63 mmHg vs. 147 ±55 mmHg, P lt;0. 05) at the time of 24 hours after NPPV treatment as compared with baseline. There were no significant change after NPPV treatment in heart rate, APACHEⅡ score, pH and PaCO2 ( all P gt;0. 05) . On the other hand in the failure subgroup, after 24 hours NPPV treatment, respiratory rate significantly increased( 40 ±3 breaths /min vs. 33 ±3 breaths /min, P lt;0. 05) and PaO2 /FiO2 showed a tendency to decline( 98 ±16 mmHg vs. 123 ±34 mmHg, P gt; 0. 05) . Conclusions In selected patients, NPPV is an effective and safe intervention for ALI/ARDS with improvement of pulmonary oxygenation and decrease of intubation rate. The results of current study support the use of NPPV in ALI/ARDS as the firstline choice of early intervention with mechanical ventilation.
Objective To explore the role of renin-angiotensin system( RAS) in acute lung injury( ALI) /acute respiratory dysfunction syndrome( ARDS) by using amouse cecal ligation and puncture ( CLP)model.Methods The ALI/ARDS animal models were assessed bymeasuring blood gas, wet/dry lung weight ratio( W/D) , and lung tissue histology 18 hours after CLP operation. After the ALI/ARDS models was successfully established, immunohistochemistry, western blotting and radioimmunity were used to investigate the changes of several key enzymes of RAS, such as ACE, ACE2 and Ang Ⅱ. In addition, two groups of animals received a separate intraperitoneal injection of angiotensin-converting enzyme ( ACE) inhibitor captopril or recombinant mouse ACE2 ( rmACE2) after CLP, then the changes of RAS in ALI/ARDS modelswere observed. Results The extensive lung injuries can be observed in the lung tissues from CLP-treated animals 18 hours after operation. The CLP-induced ALI/ARDS led to an increase in the wet/dry weight ratio of the lung tissues, and a decrease in the PaO2 /FiO2 [ ( 194. 3 ±23. 9) mm Hg vs ( 346. 7 ±20. 5) mm Hg,P lt;0. 01] . Immunohistochemistry and western blotting tests of the lung tissues from CLP-treated animals showed a decrease in the ACE2 protein level. However, in both the CLP and sham mice there were no significant differences between the two groups. CLP markedly increased Ang Ⅱ level in lungs and plasma of mice, and RAS drugs significantly impacted the Ang Ⅱ levels of mice. Compared with the CLP group,captopril or rmACE2 led to a decrease of the Ang Ⅱ level in mice [ Lung: ( 1. 58 ±0. 16) fmol /mg,( 1. 65 ±0. 21) fmol /mg vs ( 2. 38 ±0. 41) fmol /mg; Plasma: ( 178. 04 ±17. 87) fmol /mL, ( 153. 74 ±10. 24) fmol /mL vs ( 213. 38 ± 25. 44) fmol /mL] . Conclusions RAS activation is one of the characteristics of CLP-induced ALI/ARDS in mice models. ACE and ACE2 in RAS have a different role in the regulation of AngⅡ synthesis, while ACE has a positive effect in generating AngⅡ, and ACE2 shows a negative effect.
Objective To investigate the transduction pathway of TREM-1 during endotoxininduced acute lung injury ( ALI) in mice through the specific activating or blocking TREM-1.Methods 40 mice were randomly divided into a saline control group, an ALI group, an antibody group, and a LP17 group ( 3.5 mg/kg) . All mice except the control group were intraperitoneally injected with lipopolysaccharide ( LPS) to establish mouse model of ALI. Two hours after LPS injection, anti-TREM-1mAb ( 250 μg/kg) was intraperitoneally injected in the antibody group to activation TREM-1, and synthetic peptide LP17 was injected via tail vein in the LP17 group to blocking TREM-1. After 6,12,24, 48 hours, 3 mice in each group were sacrificed for sampling. The expression of NF-κB in lung tissue was determined by immunohistochemistry. The levels of TNF-α, IL-10, TREM-1, and soluble TREM-1 ( sTREM-1) in lung tissue and serumwere measured by ELISA. Pathology changes of lung were observed under light microscope, and Smith’s score of pathology was compared. Results Administration of anti-TREM-1mAb after ALI modeling significantly increased the NF-κB expression in lung tissue at 48h, resulting in a large number of pro-inflammatory cytokines releasing in the lung tissue and serumand lung pathology Smith score increasing. Administration of LP17 after modeling significantly down-regulated the expressions of NF-κB and pro-inflammatory cytokines, while led to a slight increase of anti-inflammatory cytokines and a decline of lung pathology Smith’s score.Conclusion TREM-1 may involve in inflammatory response by promoting the generation of inflammatory factors via NF-κB pathway, thus lead to lung pathological changes in ALI.
Objective To investigate the role of angiotensin-II type 1 receptor ( AT1) antagonist in treatment of acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) . Methods Animal model of ALI/ARDS was induced by cecal ligation and perforation ( CLP) . ALI/ARDS animals received a separate intraperitoneal injection of several concentrations( 5, 10, 15, 20, 25 mg/kg) of AT1 inhibitor losartan after CLP, then the changes of lung injury and 7-day survival were measured. Results Oxygenation index and lung wet to dry weight ratio ( W/D) showed an improving trend when losartan was administered at doses of 5 to 15 mg/kg in ALI/ARDS rats, but aggravated above the dose of 15 mg/kg. Losartan ( 15 mg/kg) treatment significantly alleviated pulmonary edema after CLP operation, and decreased serumlevels of TNF-α, IL-6, andIL-1β [ TNF-α: ( 554. 1 ±62. 7 ) pg/mL vs. ( 759. 2 ±21. 5 ) pg/mL, P lt; 0. 01; IL-6: ( 1227. 3 ±130. 0) pg/mL vs. ( 2670. 4 ±174. 1) pg/mL, P lt; 0. 01; IL-1β: ( 444. 0 ±38. 6) pg/mL vs. ( 486. 6 ±61. 7)pg/mL, P lt; 0. 05] . 7-day survival rate also increased in losartan treatment group at a dose of 15 mg/kg( 6. 7% vs. 0 ) . Conclusions The AT1 inhibitor, losartan, can significantly prevent lung injury in ALI/ARDS after CLP, and improve the 7-day survival rate.
Objective To investigate the influence of chronic alcohol ingestion on the severity of acute lung injury (ALI) induced by oleic acid and lipopolysaccharide (LPS).Methods Thirty-two SD rats were randomly administrated with alcohol or water for 6 weeks，then instilled with oleic acid and LPS to induce ALI or with normal saline as control.Thus the rats were randomly divided into two injury groups [ethanol group and water group] and two control groups [ethanol group and water group] (n=8 in each group). PaO2,Wet to dry lung weight ratio (W/D)，levels of γ-glutamylcysteinylglycine (GSH) and malonaldehyde (MDA) in the lung tissue were measured.Results Compared to corresponding control groups，the PaO2 and GSH significantly decreased，and the lung W/D and MDA level were significantly increased in the injury groups (all Plt;0.05).In the injury groups，the changes of above parameters were more significant in the alcohol group than thoe in the water group (all Plt;0.05)，except the lung W/D with no significant difference.Conclusion Chronic ethanol ingestion was relevalent to oxidation/ antioxidation imbalance and more severe lung injury in rats with severe septic after trauma,which suggests that chronic alcohol abuse could increase the severity of acute lung injury.
ObjectiveTo investigate the protective effect and mechanism of arbutin on LPS induced Acute lung injury in mice. Methods SPF BCLB/C mice were randomly divided into control group, model group,arbutin group, and arbutin+PI3K inhibitor group.arbutin group and arbutin+PI3K group were intervened with corresponding drugs respectively; Constructing an ALI model by intranasal instillation of LPS into mice; After modeling for 6 hours, the mice were killed. After staining the lung tissue slices, observe the pathological changes of the lung tissue and evaluate the lung injury score, and calculate the wet to dry weight ratio (W/D); ELISA method was used to determine the levels of TNF-a and IL-6 in serum and bronchoalveolar lavage fluid (BALF); Measure the ROS content, MDA level,and MPO activity in the lungs; Western blot method was used to detect the expression of PI3K/Akt/mTOR pathway related proteins and autophagy related proteins Beclin-1 and LC3II/I. ResultsCompared with the control group, the pathological changes in the lung tissue of model group mice worsened, and the W/D and lung injury scores increased, The levels of IL-6 and TNF-a in BALF and serum was increased, The ROS content, MDA expression and MPO activity in the lungs was increased,the expression of Beclin-1 and LC3II/I in the lungs was increased. The expression of PI3K/Akt/mTOR pathway related proteins in the lungs decreased (P<0.05). Compared with the model group, the pathological changes in the lung tissue of arbutin group mice were alleviated, with a decrease in W/D and lung injury score, The levels of IL-6 and TNF-a in BALF and serum decrease,ROS content, MDA expression and MPO activity in lung were decreased.The expression of PI3K/Akt/mTOR pathway related proteins in the lung was increased, The expression of Beclin-1 and LC3II/I decreased. However, the appeal performance was partially blocked in the arbutin+PI3K group after the administration of LY294002.ConclusionsArbutin regulates autophagy through PI3K/Akt/mTOR pathway to inhibit inflammatory response and oxidative stress in LPS-induced ALI mice, and plays a protective role in LPS-induced ALI.