| Part one Building one-lung ventilation model in rabbits and comparisons of three kinds of methodsTest one: Rabbit model of One-lung ventilation.Objective The purpose of this study was to build an experimental model of one lung ventilation (OLV) in rabbits.Method Ten rabbits weighing 2.3±0.2kg were anesthetized with ketamine (25 mg/kg, IM). A double-lumen endotracheal tube made by myself was inserted, and mechanical ventilation with 100% oxygen was used during the study. The ventilator settings were VT = 10 ml/kg, respiratory frequency = 40breaths/min and inspiratory-expiratory rate = 1:2. Mean arterial pressure, heart rate, pressure of air way and arterial blood gases were recorded in three phases: 5 minutes before OLV, 30 minutes after beginning OLV and 30 minutes after returning to two-lung ventilation (TLV). Result This rabbit model of OLV is convenient, satisfactory and safety. The changes of Mean arterial pressure, heart rate, pressure of air way and arterial blood gases were similar to clinical.Conclusion The rabbit model of OLV was easy to perform and could reduce the spending of animals and equipments. This model is suitable for the investigation of the pathophysiological mechanism and possible protective interventions to lung injury and hypoxia induced by OLV.Test two: A comparison of three kinds of One-lung ventilation models in rabbits. Objective The purpose of this study was to compare three kinds of one-lung ventilation (OLV) models in rabbits.Method 30 rabbits weighing 2.3±0.2kg were anesthetized with ketamine (25 mg/kg, IM) and were ventilated via tracheotomy tubes at a rate of 40/min with a tide volume of 10 ml/kg with pure oxygen and divided randomly into three groups. In group A (n=10) OLV was carried out by a artificial double-lumen endotracheal tube. In group B thoracotomy was performed and the left main bronchus was completely clamped with a clip, so OLV was carried out. In group C tracheotomy tube was pushed into the right main bronchus to perform OLV. The successful rates of first time and overall, the time from tracheotomy beginning to OLV beginning and volume of bleeding were recorded. The rabbit's tracheal was measured.Result In group A, the success rates of first time and overall were higher than group B and group C. The numbers of three groups coming into experiment were respectively 10, 6, 8. In group A the time from tracheotomy beginning to OLV beginning were significantly than group B and group C(P<0.01). To compared with group B the bleeding volume was significantly lower in group A (P<0.01).Conclusion The rabbit model of OLV performed by the artificial double-lumen endotracheal tube is convenient, satisfactory and safe. This model is suitable for the investigation of the pathophysiological mechanism associated with OLV. Part 2 Character of one-lung ventilation induced lung injury and the effect of different durations on lung injury degrees of bilateral lungsObjective To investigate the character of one-lung ventilation induced lung injury and the effect of different durations on lung injury degrees of bilateral lungs.Methods 24 white Japanese rabbits were divided into 4 groups (n = 6). The control group performed two-lung ventilation for 2h. The groups of O1,O2 and O3 performed one-lung ventilation for 1h,2h and 3h respectively, which were followed with two-lung ventilation for 1h. Lung separation was achieved with a artificial double-lumen tube. The blood samples were drawn from femoral artery,the right pulmonary vein and the left one to get the oxygenation indexes. Light microscopic evaluations were performed to get the lung injury scores. Wet/dry ratios (W/D), MDA,SOD,myeloperoxidase (MPO) activity were measured with corresponding methods.Results Lung injury scores were significant differences in left lung compared to right lung in the groups of O1,O2 and O3, though no significant differences were noted in the group C. Comparison of the right lungs of the four groups documented significant increase of lung injury scores. Compared with O1 group, Lung injury scores in O3 group was significantly elevated(P<0.05). The changes in the left lung were similar and more severe to the right ones. Compared with C group, Lung injury scores in O1 group was significantly elevated(P<0.01). Compared with O1 group, Lung injury scores in O2 and O3 groups were significantly elevated(P<0.01). Similar changes of oxygenation index,W/D,MDA and MPO activity were found in all the groups, which were significant differences in left lung compared to right lung in the groups of O1,O2 and O3, though no significant differences were noted in the group C. Comparison of the right lungs of the four groups documented significant increase of lung injury scores. Compared with O1 group, O3 group was significantly elevated(P<0.05). The changes in the left lung were similar and more severe to the right ones. Compared with C group, O1 group was significantly elevated(P<0.01). Compared with O1 group, O2 and O3 groups were significantly elevated(P<0.01). SOD was significant differences in left lung compared to right lung in the groups of O2 and O3. Compared with C group, SOD in right and left lung of O1 group were significantly decreased(P<0.01).SOD in right of O3 group was less than O1 group(P<0.01). SOD in left of O2 and O3 group were less than O1 group(P<0.01).Conclusion Long time OLV could provoke acute lung injury, which was inhomogeneous. The degrees of lung injury were related to OLV duration and were more severe in the non-ventilated lung.Part 3 Effects of nuclear factor- B on one-lung ventilation induced lung injuryObjective To study the changes of nuclear factor- B activation and expression of cytokines in lung tissues after one lung ventilation on the rabbit models.Methods 18 white Japanese rabbits were divided into 3 groups (n = 6). The TLV group performed two-lung ventilation for 3h. The OLV group performed one-lung ventilation for 2h, which were followed with two-lung ventilation for 1h. Lung separation was achieved with a artificial double-lumen tube. The PDTC group were pretreated with pyrrolidine dithiocarbamate (PDTC) (50mg/kg, IV.) prior to one lung ventilation. The blood samples were drawn from femoral artery to get the oxygenation indexes. Light microscopic evaluations were performed to get the lung injury scores. Wet/dry ratios (W/D), MDA,SOD,myeloperoxidase (MPO) activity were measured with corresponding methods. NF-κB p65 and IκB-αwere detected with Western Blot. NF-κB activity was assayed with EMSA. TNF-αand ICAM-1 in lung tissues were detected with ELISA. The expression of TNF-αand ICAM-1 mRNA in lung tissue was measured by RT-PCR.Results (1)Lung injury scores were significant differences in left lung compared to right lung in the groups of OLV and PDTC(P<0.01). Compared with TLV group, Lung injury scores in OLV and PDTC groups were significantly elevated(P<0.05). Compared with OLV group, Lung injury scores in PDTC group was significantly decreased(P<0.01). (2) Compared with TLV group, the oxygenation of OLV and PDTC group were significantly decreased(P<0.01). Compared with OLV group, the oxygenation of PDTC group were significantly increased(P<0.05). (3) W/D,MDA and MPO activity were significant differences in left lung compared to right lung in the groups of OLV and PDTC(P<0.01). Compared with TLV group, OLV and PDTC groups were significantly elevated(P<0.01). Compared with OLV group, PDTC group was significantly decrease(dP<0.01 or P<0.05). (4)SOD was significant differences in left lung compared to right lung in OLV group(P<0.01). Compared with TLV group, OLV and PDTC groups were significantly decreased(P<0.01). Compared with OLV group, the left lung of PDTC group was significantly increased(P<0.01 or P<0.05). (5) NF-κB activity and NF-κB p65 were significant differences in left lung compared to right lung in the groups of OLV and PDTC(P<0.01). Compared with TLV group, OLV and PDTC groups were significantly elevated(P<0.01). Compared with OLV group, PDTC group was significantly decreased(P<0.01 or P<0.05). I B- was significant differences in left lung compared to right lung in the groups of OLV and PDTC(P<0.01). Compared with TLV group, OLV and PDTC groups were significantly decreased(P<0.01). Compared with OLV group, PDTC group was significantly increased(P<0.01 or P<0.05). (6) The quantity of TNF- and ICAM-1 and the expression of TNF- and ICAM-1mRNA were significant differences in left lung compared to right lung in the groups of OLV and PDTC(P<0.01 or P<0.05). Compared with TLV group, OLV and PDTC groups were significantly elevated(P<0.01 or P<0.05). Compared with OLV group, PDTC group was significantly decrease(dP<0.01 or P<0.05). Conclusion NF- B activation probably play an important role in lung injury caused by one-lung ventilation.Part 4 Effects of lung protective ventilation strategy and the fraction of inspired oxygen on lung injury degree in one-lung ventilation modelsObjective To study the effects of lung protective ventilation strategy and the fraction of inspired oxygen on lung injury degree in one-lung ventilation models.Methods 18 white Japanese rabbits were performed one-lung ventilation for 2h, which were followed with two-lung ventilation for 1h. Lung separation was achieved with a artificial double-lumen tube. The rabbits were divided into 3 groups (n = 6): (1) normal control group (A group): RR 40/min, VT 10 ml/kg and FiO2 100%; (2) protective ventilation group (B group): RR 40/min, VT 7 ml/kg, PEEP 5cmH2O and FiO2 100%; (3) protective ventilation and lower FiO2 group (C group): RR 40/min, VT 7 ml/kg, PEEP 5cmH2O and FiO2 60%. The blood samples were drawn from femoral artery to get the oxygenation indexes in three phases: 5 minutes before OLV, 30 minutes after beginning OLV and 30 minutes after returning to TLV. Light microscopic evaluations were performed to get the lung injury scores. Wet/dry ratios (W/D), MDA,SOD,myeloperoxidase (MPO) activity were measured with corresponding methods. NF-κB p65 and IκB-αwere detected with Western Blot. NF-κB activity was assayed with EMSA. TNF-a and ICAM-1 in lung tissues were detected with ELISA. The expression of TNF-a and ICAM-1 mRNA in lung tissue was measured by RT-PCR.Results (1)Lung injury scores were significant differences in left lung compared to right lung in all groups(P<0.01). Compared with A group, B and C groups were significantly decreased(P<0.05). (2) After returning to TLV, Compared with A group, the oxygenation indexes of B and C groups, which were greater than 300 while that of group A was less than 300, were significantly increased(P<0.01). (3) W/D,MDA and MPO activity were significant differences in left lung compared to right lung in all groups(P<0.01 or P<0.05). Compared with A group, B and C groups were significantly decreased(P<0.01). Compared with B group, the left lung of C group was significantly decreased(P<0.05). (4)SOD was significant differences in left lung compared to right lung in all group(sP<0.01). Compared with A group, B and C groups were significantly increased(P<0.01 or P<0.05). Compared with B group, the left lung of C group was significantly increased(P<0.01 or P<0.05). (5) NF-κB activity and NF-κB p65 were significant differences in left lung compared to right lung in all groups(P<0.01). Compared with A group, B and C groups were significantly deceased(P<0.01). Compared with B group, C group was significantly decreased(P<0.05). I B- was significant differences in left lung compared to right lung in all group(sP<0.01). Compared with A group, B and C groups were significantly increased(P<0.01). Compared with B group, the left lung of C group was significantly increased(P<0.05). (6) The quantity of TNF- and ICAM-1 and the expression of TNF- and ICAM-1mRNA were significant differences in left lung compared to right lung in all groups(P<0.01 or P<0.05). Compared with A group, B and C groups were significantly decreased(P<0.01 or P<0.05). Compared with B group C group was significantly decreased(P<0.05).Conclusion OLV with lung protective ventilation strategy and 60% inspired oxygen can attenuate lung injury by decreasing the activity of NF- B. |
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