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.
ObjectiveTo evaluate the effect of positive end-expiratory pressure (PEEP) on respiratory function and hemodynamics in acute lung injury (ALI) with intra-abdominal hypertension (IAH).
MethodsSix pigs were anesthetized and received mechanical ventilation (MV). Volume controlled ventilation was set with tidal volumn(VT) of 8 mL/kg,respiratory rate(RR) of 16 bpm,inspired oxygen concentration (FiO2) of 0.40,and PEEP of 5 cm H2O. ALI was induced by repeated lung lavage with diluted hydrochloric acid (pH<2.5) until PaO2/FiO2 declined to 150 mm Hg or less to established ALI model. Intra-abdominal hypertension was induced by an nitrogen inflator to reach intra-abdominal pressure of 20 mm Hg. Respiratory parameters and hemodynamics were continuously recorded at different PEEP levels(5,10,15,and 20 cm H2O). Every level was maintained for one hour.
ResultsPaO2/FiO2 in PEEP5,10,15 and 20 were 90±11,102±10,172±23 and 200±34 mm Hg respectively. PaO2/FiO2 in PEEP15 and 20 were significantly higher than those in PEEP5 and 10 (P<0.05). Chest wall compliance (Ccw) in PEEP5,15 and 20 were 26±3,76±15 and 85±14 mL/cm H2O respectively. Ccw in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in lung compliance (CL) in different PEEP levels (P>0.05). Plateau pressure(Pplat) in PEEP5,10,15 and 20 were 30±3,31±2,36±2 and 38±4 cm H2O respectively. Pplat in PEEP15 and 20 were significantly higher than those in PEEP5 and 10 (P<0.05). There was no significant difference in Pplat between PEEP15 and 20 (P>0.05). Heart rate (HR) in PEEP5,15 and 20 were 113±17,147±30,and 160±30 beat/min respectively. HR in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in HR between PEEP15 and 20 (P>0.05).Cardiac index (CI) in PEEP5 and 20 were 4.5±0.6 and 3.5±0.6 L·min-1·m-2 respectively. CI in PEEP20 was significantly lower than that in PEEP5 (P<0.05). There was no significant difference in CI in PEEP5,10 or 15(P>0.05). Central venous pressure(CVP) in PEEP5,15 and 20 were 12±2,17±2,and 18±3 mm Hg respectively. CVP in PEEP15 and 20 were significantly higher than those in PEEP5 (P<0.05). There was no significant difference in CVP between PEEP15 and 20 (P>0.05). There were no significant differences in MAP,SVRI,ITBVI,GEDI,PVPI,or EVLWI between different PEEP levels.
ConclusionConcomitant ALI and IAH can induce great impairments in respiratory physiology. When PEEP is gradually increased,oxygenation and the respiratory function are improved without significant secondary hemodynamic disturbances.
Objective To detect the expression of single immunoglobin IL-1 receptor related protein ( SIGIRR) in normal human lung tissues, and study its changes in alveolar epithelial cell acutely injured by lipopolysaccharide ( LPS) . Methods Twenty samples of human normal lung tissue were collected during the lobectomies. The expression of SIGIRR was detected by immunohistochemistry, western blot and RT-PCR. The human type II alveolar epithelial cell acute injury model was established by stimulating A549 cells with LPS of a final concentration of 10 μg/mL. The cells were collected at 0, 3, 6, 12, and 24 hours after the stimulation. The changes of SIGIRR expression at the same time points were observed by western blot. The expression vector containing full-length SIGIRR cDNA was transfected transiently into A549 cells to induce SIGIRR overexpression. MTT assay was performed to measure the injury of A549 cells caused by LPS. Results The immunohistochemistry, western blot and RT-PCR showed that there was a high expression of SIGIRR in normal human lung tissues. The expression of SIGIRR was located in alveolar epithelial cells by immunohistochemistry. The expression of SIGIRR at 3, 6, and 12 hours was down-regulated after LPSstimulation and raised again at 24 hours to the baseline. MTT assay showed that SIGIRR overexpression substantially reduced the growth inhibition ratio of A549 cells after LPS stimulation. Conclusions Expression of SIGIRR in normal human lung tissues was confirmed by different detection methods. SIGIRR alleviates the injury of alveolar epithelial cells caused by LPS, implying SIGIRR might be involved in the regulationof acute lung injury mediated by LPS.
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.
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 effects of mechanical ventilation( MV) via different tidal volume ( VT) in combination with positive end expiratory pressure( PEEP) on dogs with acute lung injury( ALI) . Methods Dog model of oleic acid-induced ALI was established. And after that animals were randomized into different MV groups ( included low VT group, VT =6 mL/kg; and high VT group, VT =20 mL/kg) and ventilated for 6 h with a PEEP of 10 cmH2O. Arterial blood gas wasmeasured before, during and after ALI model was established ( at 1 h,2 h, 4 h and 6 h during MV) . The albumin concentration in BALF and pathological change of the lung tissue were evaluated in order to determine the lung injury while animals were sacrificed after 6 h MV. Results ALI model was successfully established ( 2. 50 ±0. 80) hours after oleic acid injection. Arterial pH decreased much severer in the low VT group than the high VT group( P lt;0. 01) . PaO2 and SaO2 in ventilation groups decreased after modeling but increased after MV, and PaO2 and SaO2 were significantly higher in the low VT group than the high VT group after 6 h MV( P lt;0. 05) . PaCO2 fluctuated less in the high VT group, while it increased significantly in the low VT group after MV( P lt; 0. 01) . Oxygenation index( PaO2 /FiO2 ) was lowered after modeling( P lt; 0. 01) , decreased to about 190 mm Hg after 1 h MV. And PaO2 /FiO2 in low VT group was significantly higher than the high VT group after 6 h MV( P lt; 0. 05) . BALF albumin concentration and the lung injury score in the low VT group were both significantly lower than the high VT group( both P lt; 0. 05) . Conclusions Ventilation with PEEP could improve the oxygenation of ALI dogs, and low VT ventilation improves the oxygenation better than high VT. Otherwise, low VT could induce hypercapnia and ameliorate lung injury caused by high VT MV.
Objective
To investigate
the effects of inhaled prostaglandin E1 （PGE1）on Th1/Th2 polarity in rat model of lipopolysaccharide（LPS） induced acute lung injury（ALI）.Methods Healthy adult male Wistar rats [weight （200±20）g] were randomly divided into normal control（NS） group，LPS group and PGE1 group.The model of ALI were established by injecting LPS of 5 mg/kg into caudal vein.The rats in PGE1 group inhaled aerosolized PGE1（2 μg/mL）for 30 minutes after LPS injection,then repeat the procedure 12 hours later. 1 h，6 h，12 h and 24 h after last PGE1 inhalation,enzyme linked immunosorbant assay （ELISA） was empolyed to measure the level of interferon-γ（IFN-γ）and interleukin-4（IL-4）in the serum and bronchoalveolar lavage fluid（BALF）and the ratio of IFN-γ/IL-4（Th1/Th2）was calculated.Pathological examination was made under light microscope.Results Pathological examination of lung tissue demonstrated success ALI model.Compared to NS group,the ratio of IFN-γ/IL-4（Th1/Th2）both in serum and BALF in LPS group elevated significantly（Plt;0.01）. PGE1 administration significantly decreased the ratio IFN-γ/IL-4 in serum after 6h（Plt;0.01）and in BALF at all time points（Plt;0.01）.Conclusion The imbalance of was found in the LPS induced ALI，inhaled PGE1 aerosol inhalation could restore Th1/Th2 cytokine balance in the rats model induced by LPS.
Objective To observe the level of vascular endothelium growth factor A( VEGF-A) in exhaled breath condensate ( EBC) of patients with acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) , and investigate its clinical significance. Methods EBC of 23 patients with ALI/ARDS by mechanical ventilation in intensive care unit ( ICU) were collected with improved EcoScreen condenser. EBC of 17 normal control subjects were collected with EcoScreen condensor. The level of VEGF-A was measured by ELISA in EBC and serum. The levels of VEGF-A in EBC of patients with different grades of lung injuries were compared, and the correlation was analyzed between the level of VEGF-A and clinical indicators. Results The level of VEGF-A in EBC was lower in the patients with ALI/ARDS than that of control subjects [ ( 49. 88 ±6. 32) ng/L vs. ( 56. 50 ±6. 323) ng/L, P lt;0. 01] , the level of VEGF-A was higher in the ALI patients than that of ARDS patients [ ( 53. 56 ±5. 56) ng/L vs. ( 45. 86 ±4. 45) ng/L, P lt;0. 01] ,and higher in the survival patients than that of the died patients [ ( 51. 92 ±6. 28) ng/L vs. ( 46. 05 ± 4. 58) ng/L, P lt;0. 05] . The level of VEGF-A in EBC was negatively correlated with lung injury score and A-aDO2 /PaO2 ( r = - 0. 426 and - 0. 510, respectively, P lt;0. 05) , and positively correlated with PaO2 /FiO2 and PaO2 ( r =0. 626 and 0. 655, respectively, P lt; 0. 05) . The level of VEGF-A in serum was not different between the ALI/ARDS patients and the control subjects, between the ALI and ARDS patients, or between the survival and the died patients ( all P gt;0. 05) . The level of VEGF-A in serumhad no correlation with lung injury score, A-aDO2 /PaO2 , PaO2 /FiO2 , or PaO2 ( all P gt;0. 05) . Conclusion The changes of VEGF-A in EBC of patients with ALI/ARDSmay serve as an indicator for severity and prognosis evaluation.
Objective To observe whether additional penehycl idine hydrochloride (PHC) in mechanical ventilation produces therapeutic effect on oleic acid (OA) induced acute lung injury (ALI) in canine. Methods Seventeen male canines (weighing 12-17 kg) were divided into control group (n=5), OA group (n=6) and PHC group (n=6). ALI model was developed by central venous injection of OA in canines of OA and PHC groups. ALI model was kept steady in air, all groups received mechanical ventilation 90 minutes later. Three groups received normal sal ine 0.25 mg/kg without injection of OA(control group), normal sal ine 0.25 mg/kg after injection of OA (OA group) and PHC 0.25 mg/kg after injection of OA (PHCgroup) respectively at 0 h (90 minutes after onset time of ALI/ARDS). The heart rate (HR), mean arteial pressure (MAP), mean pulmonary arterial pressure (MPAP), central venous pressure (CVP), pulmonary artery wedge pressure (PAWP), artery blood gas analysis, cardiac output (CO), extravascular lung water index (EVLWI), FiO2 and VT were observed respectively at basel ine, onset time of ALI/ARDS and 0 h, then again at 1 hour intervals for 6 hours. Besides the above, airway peak pressure (Ppeak), airway plat pressure (Pplat), mean airway pressure (Pmean) and positve end-expriatory pressure (Peep) were also observed each hour during 1-6 hours. Oxygenation index (OI), pulmonary vascular resistance (PVR), systemic vascular resistance (SVR), alveolar-arterial differences for O2 (AaDO2) and dynamic lung compl iance (DLC) were calculated and pulmonary tissue was collected for histopathologic investigation and dry wet weight ratio (WDR) test. Results The functional parameters of PHC group were improved when compared those of OA group, but there was no siginficant difference; WDR of independent region of three groups were 80.42% ± 3.48%, 82.67% ± 4.01% and 82.26% ± 1.43% respectively; WDR of dependent region of three groups were 80.51% ± 3.60%, 83.71% ± 1.98% and 82.57% ± 1.08% respectively. WDR of PHC group were obviously improved when compared with those of OA group, but there was no significant difference. Independent and dependent regions of PHC group were significantly improved when compared those of OA group in histopathologic scores, alveolar edema, inflammatory infiltration and over-distension (P lt; 0.01). Conclusion Additional PHC in mechanical ventilation produces obvious therapeutic effect on OA induced acute lung injury in canine.
Objective To investigate the serumlevel of endothelin-1 ( ET-1) in patients with acute lung injury/acute respiratory distress syndrome ( ALI/ARDS) and its clinical significance. Methods Thirty-one ALI/ARDS patients received mechanical ventilation in ICUand 25 normal subjects were recruited in the study. The patients who died in two weeks fell in death group, and the patients who did not died in two weeks fell in survival group. The serum level of ET-1 measured by EIA method were compared between thepatients with different severity of lung injury [ evaluated by American-European Consensus Conference on ARDS ( AECC) criteria and lung injury score( LIS) ] , and between the patients with different prognosis ( death or survival ) . The correlation was analyzed between the level of ET-1 and clinical parameters.Results The ET-1 level was higher in the ALI/ARDS patients than that in the control subjects [ ( 6. 18 ±4. 48) ng/L vs. ( 2. 68 ±1. 34) ng/L, P lt;0. 05] . There was no significant difference in the patients with different severity [ ALI vs. ARDS, ( 5. 43 ±4. 39) ng/L vs. ( 7. 01 ±4. 51) ng/L, P gt; 0. 05; LIS≤2. 5 vs.LISgt;2. 5, ( 5. 93 ±5. 21) ng/L vs. ( 6. 68 ±2. 76) ng/L, P gt; 0. 05] . The ET-1 level in the death group continued to increase, and higher than that in the survival group on the 5th day [ ( 7. 96 ±3. 30) ng/L vs.( 4. 36 ±3. 29) ng/L, P lt; 0. 05] . The ET-1 level was positively correlated with SIRS, SAPSⅡ and APACHEⅡ ( r = 0. 359, 0. 369 and 0. 426, respectively, P lt; 0. 05 ) , and negatively correlated with PaO2 /FiO2 and AaDO2 ( r = - 0. 286 and - 0. 300, respectively, P lt;0. 05) . Conclusion The measurementof serum ET-1 can help to evaluate the severity and prognosis of ALI/ARDS patients.
