Change in expression of macrophage migration inhibitory factor mRNA in a rat model of ventilator-induced lung injury
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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 235-260 g, were randomly divided into 3 groups （ n = 10 each） using a random number table： con- trol group （group C）, small tidal volume （VT ） mechanical ventilation group （group S） and large tidal volume me- chanical ventilation group （group L） . The animals were anesthetized with intraperitoneal ketamine 100 mg/kg, mi- dazolam 0.2 mg/kg and atropine 1.0 mg/kg. The rats were tracheostomized and spontaneous breathing was main- tained 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 collect- ed 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.
Key words:
Respiration, artificial; Respiratory distress syndrome, adult; Macrophage migration-in-Keywords:
Intraperitoneal injection
Objective To investigate the expression of aquaporin 5(AQP5)in lung tissue in a rat model of ventilator-induced lung injury(VILI).Methods Seventy pathogen free male SD rats were anesthetized with intraperitoneal 10% chloral hydrate 3.5 ml/kg,trachcostomized and mechanically ventilated.The animals were randomly assigned into 7 groups(n = 10 each)according to the tidal volume(V_T),respiratory rate(RR)and duration of mechanical ventilation: group A spontaneous breathing; group B_1,B_2(V_T 7 ml/kg,RR 50 bpm,I:E1 : 3,duration 2 h,4 h); group C_1,C_2(V_T 20 ml/kg,RR 50 bpm,I: E 1 : 3,duration 2 h,4 h)and group D_1,D_2(V_T 40 ml/kg,RR 50 bpm,I: E 1 : 3,duration 2 h,4 h).The animals were killed at the end of mechanical ventilation.The lungs were removed for microscopic examination,and determination of wet to dry lung weight ratio(W/D ratio),PMN counts in broncho-alveolar lung lavage fluid(BALF)and expression of AQP5 mRNA and protein in lung tissue.Results The expression of AQP5 mRNA and protein was significantly down-regulated while W/D ratio and PMN counts in BALF were significantly increased in group C and D than in group A and B.Conclusion The down-regulation of AQP5 expression in lung tissue may be involved in the development of lung edema during mechanical ventilation.
Key words:
Pneumonia,ventilator-associated; Aquaporin 5; Lung
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Objective To study the effects of hyperoxia on ventilator-induced lung injury(VILI) in rats.Methods 48 healthy male SD rats were randomly divided into four groups:group A received conventional mechanical ventilation(VT=8 mL/kg) with room air,group B received the same tidal volume as group A with 100% O2,group C received large tidal volume(VT=40 mL/kg) with room air,group D received the same tidal volume as group C with 100% O2.Arterial blood gases were measured every one hour and oxygenation index(PaO2/FiO2) was calculated.The changes of lung histopathology were assessed by HE staining and observed under light microscope.Wet-to-dry weight ratio(W/D) of left lung,neutrophils and white blood cell(WBC) counts in BALF were measured.Tumor necrosis factor-α(TNF-α),interleukin-1β(IL-1β),and macrophage inflammatory protein-2(MIP-2) levels in BALF,malondialdehyde(MDA),myeloperoxidase(MPO),and superoxide dismutase(SOD) levels in the lung were assayed,respectively.Results Compared with the group C,the group D demonstrated more infiltrating neutrophils in the lung and more destructive changes in the alveolar wall.Meanwhile,the oxygenation index decreased,the WBC and neutrophils counts in BALF increased,and the W/D of left lung was higher in the group D with significant differences compared with the group C.Moreover,the BALF levels of TNF-α,IL-1β and MIP-2,the lung levels of MDA increased,and the lung levels of SOD decreased significantly in the group D compared with those in the group C.There were no statistical significant differences between the group B and group A in all parameters except that MDA levels increased and SOD levels decreased significantly in the group B.Conclusion Hyperoxia can increase lung injury induced in large tidal volume ventilation in rats,but has mininmal effects in conventional mechanical ventilation.
Hyperoxia
Malondialdehyde
Oxygenation index
White blood cell
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Objective To investigate the balance between matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) in the lung tissue in a rat model of ventilator-induced lung injury. Methods Thirty healthy male SD rats weighing 200-250g were randomly divided into 3 groups( n = 10 each) : group A spontaneous breathing; group B small tidal volume (VT = 7 ml·kg-1, RR = 40 bpm, FiO2=0.21) and group C large tidal volume (VT = 40 ml·kg-1, RR = 20 bpm, FiO2=0.21). The animals were mechanically ventilated for 4 h in group B and C. The lung injury was assessed by measurement of PaO2 /FiO2 . At the end of the experiment the animals were killed and the lungs were removed. The right lung was used for determination of the expression of mRNAs of MMP-2, MMP-9, TIMP-1 and TTMP-2 using RT-PCR and histologic examination. The left lung was weighed and then lavaged. The broncho-alveolar lavage fluid (BALF) was collected for total WBC and neutrophil counts and determination of total protein content and gelatinase activity. After lavage the left lung was heated at 60℃. The W/D lung weight ratio was calculated. Results PaO2/FiO2 was significantly lower after 4h mechanical ventilation in group C than in group A and B. The total WBC count and total protein content in BALF were significantly higher in group C than in group A and B. The W/D ratio of the left lung was significantly higher in group C than in group A and B. Microscopic examination showed that there were marked WBC infiltration and destructive changes of alveolar walls in group C. The levels of gelatinase (MMP-2 and MMP-9) activities in BALF were significantly higher in group C than in group A and B. The expression of the mRNA of MMP-2 and MMP-9 was significantly higher in group C than in group A and B, but there was no significant difference in the expression of the mRNA of TIMP-1 and TIMP-2 between group C and group A and B. Conclusion Large tidal volume ventilation can induce acute lung injury. MMP-2 and MMP-9 play an important role in the development of ventilator induced lung injury and the imbalance between MMPs and TIMPs contributes to the mechanism of ventilator-induced lung injury.
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Objective
To evaluate the effect of Shenfu injection(SF) on ventilator-induced lung injury in rats and its mechanism.
Methods
Forty adult male Wister rats were equally and randomly divided into 4 groups(n=10) using a random number table :control group(group C), normal tidal volume ventilation group(group N), large tidal volume ventilation group(group L), and large tidal volume ventilation+ SF group(group SF). The spontaneous breathing of rats was maintained in group C, while the other rats were tracheostomized and mechanically ventilated for 4 h in group N, group L and group SF. Rats were killed at the end of the ventilation and was lavaged their left lung, then the bronchoalveolar lavage fluid(BALF) was collected for determination of the concentrations of protein, IL-1β, IL-18 and TNF-α. The lung tissues were removed for determination of the wet/dry(W/D) lung weight, and immunohistochemistry was used to detected the expression of NF-κB. The pathological changes of the lungs were determinated by using light microscope and the lung injury scores were also determinated.
Results
Compared with group SF[TNF-α (65±11) ng/L, IL-1β (47±9) ng/L, IL-18 (58±8) ng/L], the protein expression level of IL-1β, IL-18 and TNF-α in BALF were significantly increased in group L[TNF-α (99±7) ng/L, IL-1β (69±7) ng/L, IL-18(86±7) ng/L](P<0.05). W/D(5.0±1.6) in group SF were significantly decreased while W/D (5.5±1.8) in group L (P<0.05). The protein expression level of NF-κB were (0.32 ± 0.28) in group SF while (0.54 ± 0.33) in group L. The protein expression level of NF-κB were significantly decreased in group SF (P<0.05) and the pathological changes were also significantly reduced in group SF.
Conclusions
SF can reduce ventilator-induced lung injury in rats and its mechanism may be related to the inhibition of the activity of NF-κB pathway and reducing the release of inflammatory cytokines in the lungs.
Key words:
Shenfu injection; Mechanical ventilation; Lung injury; Nuclear factor-κB
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Objective To elucidate the effects of propofol on the phosphorylation of mitogen activated protein kinase(p38MAPK) and inflammatory lung injury in arat model of ventilator-induced lung injury(VILI). Methods Sprague-Dawley rats were randomized to three groups: standard ventilation group(Group C),high-tidal volume ventilation group(Group H),and high-tidal volume ventilation plus propofol group(Group P).During mechanical ventilation(MV),rats in Group P received intravenous propofol,while rats of group C and H received physiological saline instead.All rats were sacrificed for collection of lung lavage fluid and lung tissue.Lung wet and dry weight ratio(W/D) was calculated,and lung pathologic changes were observed under light microscope.Interleukin 1β(IL-1β),IL-6 and total protein in bronchoalveolar lavage fluid(BALF) were determined.The expression of p38 and p-p38 was measured by Western blot. Results No pulmonary pathologic change was observed in Group C.Although pathological changes were observed in Group H and P,significantly milder changes were revealed in Group P.Significant step-down of pulmonary W/D,WBC count in p-p38 and BALF,total protein content,and IL-1β and IL-6 levels was observed following the sequencing of Group H,P and C. Conclusion Propofol attenuates VILI in rats,via blocking the activation of extracellular regulated protein and reducing pulmonary inflammation.
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Objective To investigate the mechanisms of propofol on ventilator-induced lung injury in rats produced by high PIP ventilation. Methods Twenty-four anesthetized Wistar rats weighting 280 g-320 g were randomly divided into tlhree groups (n=8). Rats were ventilated with high PIP pattern (PIP=25 cm H2O,PEEP=2 cm H2O) for 4 h. Propofol was given in a bolus of 2 mg/kg (group B) or 5 mg/kg (group C), followed by continuous infusion with 4 mg·kg-1·h-1 (group B)or 10 mg·kg-1·h-1(group C). No Propofol was given for group A. MAP, HR were recorded and arterial blood gases were analyzed. Lung wet and dry weight ratio( W/D), tumor necrosis factora(TNF-α), interleukin1β(IL-1β), IL-6, IL-10, macrophage inflammatory protein2(MIP-2) and protein content in bronchoalveolar lavage fluid (BALF) , content of malondialdehyde (MDA) and superoxide dismutase (SOD) in lung homogenate were determined.Pathological change of lung was examined and lung injury was scored as well. Results MAP and PaO2 decreased from (116±7.4) mm Hg and (379±65) mm Hg to (73±21 )mm Hg and (103±48)mm Hg, and PaCO2 increased at fourth hour in group A(P<0.05). PaO2 in group B and C were higher than in group A after 3 h(P<0.05). Lung W/D weight ratio, TNF-α, MIP-2 and protein content in BALF were higher in group A (P<0.05), and MDA was higher in group A (P<0.05). No significant difference between group B and C. Pathological changes of lung in group B and C were all better than those in group A. Conclusion Propofol may attenuate VILI in rats partly by reducing the release of cytokine, decreasing the accumulation of neutrophil in the lung, and inhibiting peroxidized injury.
Key words:
Propofol; Ventilator-induced lung injury
Malondialdehyde
Arterial blood
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Objective To investigate the effect of Ketamine pretreatment in a rat model of ventilator-induced lung injury (VILI) and the possible mechanisms.Methods Sixty male SD rats were randomly divided into 3 groups (n =20 each):control group (group C),no mechanical ventilation; high tidal ventilation group (group H),and Ketamine group (group K).The set parameters of mechanical ventilation were VT =40 ml/kg,and RR =40 breathes/min.The animals were sacrificed by exsanguinations after 4 h mechanical ventilation.The wet-to-dry weight ratios (W/D),and total protein (TP) contents,WBC counts and the levels of tumor necrosis factor (TNF)-α in broncho-alveolar lavage fluid (BALF) were mesured.Nuclear factor-κB (NF-κB) protein was detected by Western blotting in each group.Results W/D,WBC counts,TP contents and the levels of TNF-α in groups H and K were [(2.18 ± 0.41),(0.29±0.12) g/ml],(5.51±0.30,4.48±0.24),[(7.10±1.30),(2.56±0.41)× 106/L],and [(451.69 ± 112.35),(198.57 ±59.76) ng/L],respectively.The average values of NF-κB protein in groups H and K were (0.47 ± 0.09) and (0.33 ± 0.08) respectively.Conclusion Pretreatment with Ketamine can significantly attenuate VILI in rats through suppressing the release of inflammatory cytokines and inhibiting the NF-κB pathway.
Key words:
Ventilator-induced lung injury; Ketamine; Nuclear factor-κB
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Objective
To investigate the effect of human interleukin-10 (hIL-10) pretreatment effect on inflammatory factors in rats with ventilator-induced lung injury (VILI).
Methods
36 healthy male SD rats, weighing 220 to 300 g, were randomly divided into three groups (n=12): control group (C group), high tidal volume mechanical ventilation group (H group) and hIL-10 treatment group (HI group). C group maintained spontaneous breathing for four hours after orotracheal intubation.In H group, VILI model was made by high tidal volume mechanical ventilation, atracurium infusion was used to inhibit spontaneous breathing and maintain muscle relaxation, small animal ventilator was used for mechanical ventilation, respiratory parameters: respiratory frequency was 40/min, duration of ventilation was four hours, inspiration time/expiratory time was 1∶3, positive end expiratory pressure was 0 cmH2O, inhaled oxygen concentration was 21%, tidal volume was 30 ml/kg, regulating according to the body weight.HI group was injected with hIL-10 (8 000 U/kg) through tail vein at 30 min before high tidal volume mechanical ventilation, C group and H group were given the same amount of saline.In each group, the rats were sacrificed after ventilation for four hours.The serum and bronchoalveolar lavage fluid (BALF) were collected to detect the concentrations of tumor necrosis factor-α (TNF-α), interleukin-8 (IL-8) and intercellular adhesion molecule-1 (ICAM-1) by enzyme-linked immunosorbent assay.The right lung tissue pathological slices were taken to observe the morphological changes by HE staining.
Results
The pathological changes were observed under light microscope.There was no obvious alveolar structure damage in C group.In H group, there were alveolar structure destruction, alveolar exudation, hemorrhage and interstitial edema, visible alveolar fusion, pulmonary septal thickening, inflammatory cell infiltration.In HI group, there was a certain degree of damage in lung tissue structure, a small amount of pulmonary septal thickening, but lighter than that in H group.Compared with C group, the concentrations of TNF-α, IL-8 and ICAM-1 in serum and BALF of H group and HI group were increased (P<0.05 or P<0.01). Compared with H group, inflammatory cytokine levels in the serum and BALF of HI group were significantly decreased (all P<0.01).
Conclusions
As an important anti-inflammatory factor, hIL-10 can reduce VILI in rats in a certain extent by regulating the inflammatory response of the lung and reducing the levels of inflammatory cytokines.
Key words:
Interleukin-10; Mechanical ventilation; Acute lung injury; Ventilator-induced lung injury
Proinflammatory cytokine
Positive End-Expiratory Pressure
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Objective
To evaluate the relationship between the shedding of syndecan-4 (SDC-4) in lung tissues and ventilator-induced lung injury in rats.
Methods
Thirty pathogen-free healthy adult male Wistar rats, weighing 220-250 g, were divided into 3 groups (n=10 each) using a random number table: control group (group C), mechanical ventilation with traditional tidal volume (VT) group (group T-VT) and mechanical ventilation with high VT group (group H-VT). The animals were anesthetized with pentobarbital sodium and tracheostomized.The rats kept spontaneous breathing in group C. The rats were mechanically ventilated for 4 h with the VT set at 6 ml/kg in group T-VT and with the VT set at 40 ml/kg in group H-VT.Blood samples were collected immediately after the end of ventilation for measurement of serum SDC-4 concentrations by enzyme-linked immunosorbent assay.The left lung was lavaged, and broncho-alveolar lavage fluid was collected for determination of interleukin-1beta (IL-1β), IL-18, tumor necrosis factor-alpha and SDC-4 concentrations by enzyme-linked immunosorbent assay.The lungs were removed for determination of the wet to dry weight ratio and expression of SDC-4 protein and mRNA in lung tissues (by Western blot and real-time polymerase chain reaction, respectively) and for examination of the pathological changes.The lung injury scores were recorded.
Results
Compared with group C, the wet to dry weight ratio, lung injury scores, concentrations of IL-1β, IL-18, tumor necrosis factor-alpha and SDC-4 in broncho-alveolar lavage fluid and concentrations of SDC-4 in serum were significantly increased, the expression of SDC-4 mRNA was up-regulated, and the expression of SDC-4 was down-regulated in group H-VT (P 0.05). Marked pathological changes of lung tissues were found in group H-VT.
Conclusion
A large shedding of SDC-4 in lung tissues may be involved in the pathophysiological mechanism of ventilatior-induced lung injury in rats.
Key words:
Syndecan-4; Respiration, artificial; Respiratory distress syndrome, adult
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Objective To investigate the effects of minute quantity of endogenous endotoxin originating from the lung on ventilator-induced lung injury in rats. Methods Thirty-two pathogen-free male adult SD rats weighing 370-390 g were randomly divided into 4 groups ( n = 8 each): group I spontaneous breathing (group C) ; group Ⅱ spontaneous breathing + IPS (group CL) ; group IE mechanical ventilation (group M) and group IV mechanical ventilation + LPS (group ML). The animals were anesthetized with intraperitoneal 20% urethane 0.8 ml/100 g. Right common carotid artery and left femoral vein were cannulated for BP monitoring and fluid and drug administration. The animals were tracheostomized. In group CL and ML LPS 100μg /kg was instilled into trachea. In group M and ML the animals were mechanically ventilated (V_T 20 ml/kg, PEEP=0, I = E = 1:1). P_(ET) CO_2 was maintained at 35-45 nun Hg by adjusting respiratory rate. The animals were breathing or ventilated with room air,and ECG, BP, HR and P_(ET)CO_2 were continuously monitored. Blood gases were analyzed at the beginning and 1, 2 and 3 h of experiment. The animals were sacrificed at 3 h of experiment. The lungs were removed for microscopic examination. The pathological changes of the lung were scored (0 = normal,3 = severe change) . Wet/dry lung weight ratio was determined. The left lung was lavaged. The broncho-alveolar lavage fluid (BALF) was collected. WBCs in BALF were counted. Pulmonary albumin permeability (PAP) (BALF protein concentration/plasma protein concentration) was determined. Plasma TNF-a and macrophage inflammatory protein 2 (MIP-2) concentrations were detected with ELISA. The endotoxin receptor CD14 mRNA expression in lung tissue was determined by RT-PCR and the macrophage CD14 expression in BALF was determined by immuno histochemistry in group C and M. Results Wet/dry lung weight ratio and PAP were significantly higher in group ML than in group M and C. WBC count in BALF, the pathological score and plasma MIP-2 concentration were significantly higher in group M and ML than in group C and were significantly higher in group ML than in group M. TNF-a concentration was significantly higher in group CL and ML and was not detected in group C and M. CD14mRNA expression in the lung tissue and CD14 expression in BALF macrophage were significantly higher in group M than in group C. Conclusion Minute amount of endogenous endotoxin from the lung can aggravate ventilator-induced lung injury in rats. Mechanical ventilation with large tidal volume sensitizes the lung to LPS stimulation through up-regulation of CD14 exexpression.
Key words:
Endotoxins; Respiration, artificial; Respiratory distress syndrome, adult
Femoral vein
Respiratory Rate
Arterial blood
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