ABSTRACT
Objective To investigate the role of Ras-related C3 botulinum toxin substrate 1/mitogen-activated protein kinase/extracellular signal-regulated kinase (Rac 1/MAPK/ERK) signal pathway in rats with ventilator induced lung injury (VILI) and its mechanism.Methods Thirty Sprague-Dawley (SD) rats were randomly divided into spontaneous respiration group,normal tidal volume (VT) group and high VT group with 10 rats in each group.The rats in spontaneous respiration group were kept their spontaneous breathing.The rats in normal VT group and high VT group were performed tracheal intubation after tracheostomy,and underwent mechanical ventilation on bilateral lungs with 6 mL/kg and 40 mL/kg VT respectively with maintenance anesthesia.After 4-hour ventilation,heart blood,bronchoalveolar lavage fluid (BALF) and lung tissues were harvested.The levels of interleukins (IL-1β,IL-6),tumor necrosis factor-α (TNF-α),myeloperoxidase (MPO) and macrophage inflammatory protein-2 (MIP-2) in serum and BALF were determined by enzyme linked immunosorbent assay (ELISA).Lung wet/dry radio (W/D) was determined.The lung tissues were stained with hematoxylin and eosin (HE),and pathological changes were observed,and pathological scores were evaluated.The ultra structure changes in type Ⅱ alveolar epithelial cells (AEC Ⅱ)were observed with transmission electron microscope.The positive expressions of phosphorylation of extracellular signal-regulated kinase (p-ERK) were determined by immunohistochemistry,and those of Racl and F-actin were determined by immunofluorescence.The mRNA expressions of ERK and Rac1 were determined by real-time fluorescent quantitation reverse transcription-polymerase chain reaction (RT-qPCR),and protein expressions of Rac-1,p-ERK and F-actin were determined by Western Blot.Results ① Compared with spontaneous breathing group,lung W/D in both mechanical ventilation groups was significantly increased,with more significant increase in the high VT group (6.64 ± 0.88 vs.1.79 ± 0.36,P ＜ 0.01).② There was no obvious pathological changes in the lung tissue and AEC Ⅱ of the spontaneously breathing group.In the normal VT group,there was slight edema and infiltration of inflammatory cells;AEC Ⅱ had less lamellar bodies and uniform distribution of the villi of the alveolar epithelium.In the high VT group,the edema of the lung tissue,the widening of the pulmonary septum,the alveolus congestion,the infiltration of inflammatory cells,and alveolar structure disorder were found;and AEC Ⅱ was irregular,the number of lamellar bodies in the plastids was decreased and was unevenly distributed.The pulmonary histopathological score in the high VT group was significantly higher than that in the spontaneous breathing group and the normal VT group (12.00 ± 2.00 vs.6.00 ± 1.51,8.50 ± 0.53,both P ＜ 0.01).③ Compared with spontaneous breathing group,IL-1β,IL-6,TNF-α,MPO,and MIP-2in serum and BALF in both mechanical ventilation groups were significantly increased,with more siguificant increase in the high VT group [serum IL-1 β (ng/L):104.2 ± 15.1 vs.20.3 ± 8.3,IL-6 (ng/L):46.6 ± 11.5 vs.22.7 ± 7.5,TNF-α (ng/L):39.4±6.5 vs.5.4± 1.9,MPO (ng/L):0.66±0.24 vs.0.06±0.03,MIP-2 (ng/L):109.2±25.8 vs.22.8±8.4;BALF IL-1 β (ng/L):121.5 ± 25.6 vs.24.0 ± 7.5,IL-6 (ng/L):136.7 ± 32.7 vs.31.4 ± 10.5,TNF-α (ng/L):98.0 ± 14.8vs.10.1 ±2.6,MPO (ng/L):0.80±0.31 vs.0.08±0.04,MIP-2 (ng/L):144.4±28.9 vs.41.2±20.7;all P ＜ 0.01].④ There were only a few p-ERK,Rac1 and F-actin positive expressions in the spontaneous breathing group.The positive expressions in normal VT group were increased.In high VT group,the positive expression of p-ERK was significantly increased;Rac1 and F-actin were mainly distributed in the cell membrane and cytoplasm respectively,the positive expressions were further enhanced.⑤ The gene expressions of ERK and Rac1,and protein expressions of p-ERK,Rac1 and F-actin in the high VT group were significantly higher than those in the spontaneous breathing group and normal VT group [ERK mRNA (2-△△Ct):8.23±2.83 vs.1,3.02± 1.38,p-ERK protein (gray value):1.15±0.36 vs.0.61 ±0.23,0.88±0.22;Rac1 mRNA (2-△△Ct):4.45 ±2.26 vs.1,1.22±0.39,Rac1 protein (gray value):0.91 ±0.16 vs.0.48±0.11,0.55 ± 0.10;F-actin protein (gray value):0.70± 0.09 vs.0.49 ± 0.08,0.55 ± 0.04;all P ＜ 0.01].Conclusion F-actin expression in lung tissue was up-regulated in rats with VILI,which resulted in reconstruction of AEC Ⅱ cyto-skeleton,and variation of cell membrane permeability through Rac 1 /MAPK/ERK sigualing pathway during VILI.
ABSTRACT
Objective To explore the effects of penehyclidine hydrochloride (PHC) on lung epithelial type Ⅱcells against oxidative stress damage. Methods A549 cells treated with H2O2 were used as oxidative stress damage cell model. A549 cells were divided into 3 groups: control group (C group), H2O2 treated group (H group) and PHC treated group (P group). The viability of A549 cells was measured by MTT assay. The apoptotic rate was measured by TUNEL assay. The lev?els of malonicdialed (MDA), reactive oxygen species (SOD), reduced glutathione hormone (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH) of cells were detected by biochemistry colorimetry. Results Compared with group C, the viability of A549 and the contents of SOD, GSH and NADPH were significantly decreased in group H, while MDA content and apoptotic rate were increased (P<0.05). Compared with group H, the viability of A549, the contents of SOD, GSH and NADPH were significantly increased in group P, while MDA content and apoptotic rate were reduced (P<0.05). Conclu?sion Penehyclidine hydrochloride shows protective effects on A549 cells through reducing the oxidative damage induced by H2O2.
ABSTRACT
Objective To investigate the role of Toll-like receptor9 (TLR9)-myeloid differentiation factor 88 (MyD88) signal pathway in alveolar macrophages in ventilator-induced lung injury (VILI).Methods 30 adult male Sprague-Dawley (SD) rats were randomly assigned to three groups (with 10 rats in each group).Group A was the control group,with spontaneous respiration after tracheostomy.Rats in group B received mechanical ventilation for 4 hours with normal tidal volume (VT) 7 ml/kg after tracheostomy,and group C rats received mechanical ventilation with VT 40 ml/kg for 4 hours.After termination of ventilation,examination with transmission electron microscopy was performed to observe the ultrastructure changes in alveolar epithelial cell type Ⅱ (AEC Ⅱ) of the lung.Lung wet/dry ratios (W/D) and total protein concentration,the concentration of interleukins (IL-6 and IL-1 β) in bronchoalveolar lavage fluid (BALF) were determined.The protein and mRNA expressions of TLR9,MyD88 and nuclear factor-κB (NF-κB) in alveolar macrophages were assayed by Western Blot and real-time reverse transcription-polymerase chain reaction (RT-PCR).Results The ultrastructure of AEC Ⅱ in the group A and group B was almost normal,whereas the chromatin of the nuclei,the lamellar corpuscles in the cytoplasm,the cell membrane and the microvilli of the AEC Ⅱ in the group C showed injurious changes in various degrees.When the group C was compared with the group A and the group B,it was shown that the W/D ratios (5.54 ± 0.17 vs.4.58 ± 0.17,4.69 ± 0.16) and total protein concentration (g/L:6.33 ± 0.61 vs.0.45 ± 0.05,0.47 ± 0.04),IL-6 (μg/L:1.989 ± 0.103 vs.1.033 ± 0.061,1.010 ± 0.069) and IL-lβ (ng/L:2.79 ±0.25 vs.1.05 ±0.15,1.23 ±0.22) in BALF,the protein expressions of TLR9,MyD88 and NF-κB [TLR9 (A value):0.770 ±0.042 vs.0.300 ±0.027,0.310 ±0.037; MyD88 (A value):0.950 ±0.091 vs.0.560 ±0.082,0.580±0.084; NF-κB(A value):1.020 ±0.076 vs.0.740 ±0.052,0.700 ±0.076] in alveolar macrophages were all increased significantly,and all of which showed significant difference (P＜0.05 or P＜0.01).The mRNA levels of TLR9,MyD88 and NF-κB in alveolar macrophages in the group B were (1.13 ± 0.32),(1.18 ± 0.33),and (1.11 ± 0.22) folds of those of the group A,respectively,but there were no significant differences (all P＞0.05).While the mRNA levels of TLR9,MyD88 and NF-κB of alveolar macrophages in the group C were (8.66 ± 0.69),(6.41 ± 0.53) and (5.29 ± 0.71) folds of those of the group A,respectively,and all of them showed significant difference (all P＜0.01).Conclusion TLR9-MyD88 signaling in alveolar macrophages plays a role in pathogenesis of VILI.
ABSTRACT
Objective To evaluate the role of Toll-like receptor 2/nuclear factor-κB(TLR2/NF-κB)signaling pathway pretreatment in ventilator-induced lung injury(VILI). Methods Thirty male Sprague-Dawley(SD)rats were randomly divided into three groups by using random number scale,with 10 rats in each group. Group A:rats were given 200μL of TLR2 monoclonal antibodies(TLR2mAb,10μg/kg)by slow instillation through tracheal catheter, and then ventilated with a high tidal volume(VT)of 40 mL/kg. Group B:ventilated with a normal VT of 8 mL/kg. Group C:rats were tracheally instilled with 10 μg/kg of TLR2mAb devoid of biologic activity,and then ventilated with a high VT of 40 mL/kg. The rats were mechanically ventilated for 4 hours,the lung wet to dry weight ratio(W/D)was calculated. The changes in pathology and ultrastructure in lung tissue were observed with microscope. Enzyme linked immunosorbent assay(ELISA)was performed to determine the concentration of interleukins(IL-1β,IL-6)and tumor necrosis factor-α(TNF-α)in serum and brconchoalveolar lavage fluid(BALF). Real-time fluorescent quantitation reverse transcription-polymerase chain reaction(RT-PCR)was used to assess the mRNA expressions of TLR2, NF-κB and myeloid differentiation factor 88(MyD88)in lung tissue. Results No obvious pathological changes in lungs were found in group A and group B,and no obvious damages to ultra-microstructure were found in lung macrophages, typeⅠepithelial cell and typeⅡepithelial cell. In group C,pathological changes were observed,including pulmonary alveoli fusion,alveoli septum thickening,inflammatory cells infiltration,and damages to ultrastructure of lung macrophage,damage to cell membrane of typeⅠepithelial cells and typeⅡepithelial cells,vacuoles in cytoplasm, damage to organelle,and even pyknosis and perinuclear cistern thickening. Compared with group C,W/D ratio and mean concentration of inflammatory cytokines in serum and BALF showed a significant decrease in group A and B〔W/D ratio:1.151±0.026,1.128±0.048 vs. 1.403±0.062;concentration of IL-1βin serum(ng/L):37.05±5.61, 34.52±4.31 vs. 51.45±8.18;concentration of IL-6 in serum(ng/L):53.65±5.16,55.77±5.62 vs. 89.96±7.08;concentration of TNF-αin serum(ng/L):71.93±13.29,67.36±11.42 vs. 96.20±11.60;concentration of IL-1βin BALF(ng/L):56.48±6.16,54.44±7.26 vs. 99.77±8.41;concentration of IL-6 in BALF(ng/L):172.44±21.26, 163.47±18.70 vs. 216.22±23.90;concentration of TNF-α in BALF(ng/L):235.81±42.75,231.72±40.38 vs. 374.85±69.61,all P0.05). The mRNA expressions of TLR2,MyD88,and NF-κB were significantly decreased in group A and group B compared with those in group C〔TLR2 mRNA(2-ΔΔCt):1.021±0.287,0.938±0.196 vs. 3.862±0.871;MyD88 mRNA (2-ΔΔCt):1.235±0.277,1.300±0.306 vs. 3.618±1.107;NF-κB mRNA(2-ΔΔCt):0.519±0.036,1.043±0.170 vs. 20.280±9.466,P0.05). Conclusion To some extent,pre-intervention with TLR2mAb to block the TLR2/NF-κB signal pathway can inhibit the release of pro-inflammatory factors,and regulate the VILI.
ABSTRACT
The aim was to investigate the effects of two different ventilatory strategies: Pressure-controlled ventilation [PCV] versus volume-controlled ventilation [VCV] in elderly patients with poor pulmonary function during one-lung ventilation [OLV]. The patients were enrolled into the study having poor pulmonary function [forced expiratory volume in 1 s <1.5 L] and undergoing radical resection of pulmonary carcinoma requiring at least 2 h of OLV. Patients were respectively allocated to VCV group and PCV group. The intraoperative data, arterial, and mixed venous blood gases were obtained at baseline, 20, 40, 60, 80, 100 and 120 min after OLV and end of surgery. The postoperative data had been recorded and arterial gas measurements were performed at 6, 12 and 24 h after surgery in Intensive Care Unit. Comparison of the VCV group and PCV group, PaO[2] and P[A-a]O[2] were higher and dead space to tidal volume was lower in the PCV group [P < 0.05] after the point of OLV +60, Ppeak was higher in the VCV group [P < 0.05]. There were significant advantages in PCV groups with regard to the PaO[2] of three points in postoperation, the duration of postoperative ventilation duration, intensive care duration of stay and the days stay in hospital after surgery. The use of PCV compared with VCV during OLV in elderly patients with poor pulmonary function has significant advantages of intraoperative and postoperative oxygenation and it might be a factor, which can beneficial to postoperative recovery
ABSTRACT
Objective To investigate the changes in the expression of macrophage migration inhibitory factor (MIF) mRNA in a rat model of ventilator-induced lung injury.Methods Thirty adult male Sprague-Dawley rats,weighing 2β5-260 g,were randomly divided into 3 groups (n =10 each) using a random number table:control group (group C),small tidal volume (VT) mechanical ventilation group (group S) and large tidal volume mechanical ventilation group (group L).The animals were anesthetized with intraperitoneal ketamine 100 mg/kg,midazolam 0.2 mg/kg and atropine 1.0 mg/kg.The rats were tracheostomized and spontaneous breathing was maintained in group C,while the rats were tracheostomized and mechanically ventilated for 4 h in groups S and L.The tidal volume was 7 ml/kg (group S) or 40 ml/kg (group L),I ∶ E was 1 ∶ 1,RR was 80 bpm and FiO2 was 100％.At 4 h of spontaneous breathing or mechanical ventilation,broncho-alveolar lung lavage fluid (BALF) was collected for determination of the total protein concentration,white blood cell (WBC) counts and concentrations of MIF,IL-6 and IL-1β (by ELISA).Then the rats were sacrificed and the lungs removed for microscopic examination and for determination of wet to dry lung weight ratio (W/D ratio) and expression of MIF mRNA (by RT-PCR).Results Compared with C and S groups,WBC counts,concentrations of total protein,MIF,IL-6 and IL-1β in BALF,and W/D ratio and expression of MIF mRNA in lung tissues were significantly increased in group L (P ＜ 0.05).There was no significant difference in the indexes mentioned above between group C and group S (P ＞ 0.05).The pathological changes occurred in group L.Conclusion The up-regulation of MIF mRNA expression in lung tissues may be involved in the development of ventilator-induced lung injury in rats.