Effects Of Nicorandil On Lung Injury Induced By Collapse In One-lung Ventilation And Its Mechanisms

Objective To observe nicorandil's lung protection effect and explore its mechanisms furtherly by the establishment of mature rabbit one-lung ventilation?OLV?model,which is simulated according to clinical operation.Methods The induction and maintenance of anesthesia were operated after the establishing of channel at ear margin vein in rabbit.We monitored arterial blood pressure and attained arterial blood samples through the right common carotid artery catheter.The homemade double lumen endotracheal tube was inserted by tracheotomy before the implementation of mechanical ventilation.Ringer's lactate fluid was infused to reduce the loss of body fluid during the process of ventilation and blood sampling and maintain physiological balance.Homemade double lumen endotracheal tube?DLT?was inserted to juga part,and the left side of the pipe was inserted into the left main bronchus.The tube and main trachea were ligated with bold line avoiding leakage near the cut of trachea.Whether to implement successfully OLV was as follows: Firstly,we clamped the left and right tube of DLT respectively to judge by the change of breath sound through auscultation and adjust the position of DLT.Secondly,if there was not air bubble,which was a good way,we could evaluate the leakproofness of left tube.Lastly,after rabbit was adjusted to right lateral position,1 cm incision was opened on the left chest rib gap to directly observe whether the left lung was collapsed,so as to determine whether the rabbit OLV model was successfully established.OLV was implemented in 1h,then TLV was implemented in 1h,in order to simulate the clinical effect of one-lung ventilation.The success rate of the model was recorded.Heart rate?HR?,arterial blood pressure?ABP?,airway pressure?Pairway?and arterial blood gas analysis were recorded at three time points,which were before one-lung ventilation?T₁?,30 min after OLV?T₂?and 30 min after TLV?T₃?.Results The success rate of the model was 100%.The MAP,HR,Pairway,SaO₂,Pa O2,PaCO₂ are located in the normal range at T₁.The Pa O2 and SaO₂ decreased significantly at T₂?P<0.01?,increased at T₃.The trend of PaCO₂ was opposite?P<0.01?.The Pairway significantly increased at T₂?P<0.01?,decreased at T₃.All the parameters of the model is consistent with that of the clinical one-lung ventilation.Conclusion We observed effects and mechanisms of nicorandil on lung injury induced by collapse in mature rabbit OLV model on the basis of this research,which was consistent with clinical one-lung ventilation.Objective To investigate the effects of nicorandil on lung injury of the collapsed lung in rabbit OLV model.Methods Thirty clean rabbits were randomly divided into sham group?group S??two-lung ventilation+thoracotomy?,negative control group?group C??one-lung ventilation+thoracotomy+saline?,nicorandil group?group N??one-lung ventilation+thoracotomy+nicorandil?and antagonist group?group J??one-lung ventilation+thoracotomy+ nicorandil +glibenclamide?equally.Nicorandil was infused by 100?g/kg·h,lasting 1h,in group N.Nicorandil was infused by 50?g/kg·h,lasting 1h,in group D.The same volume saline was infused in S and C groups.Nicorandil was infused by 100?g/kg·h with glibenclamide by 75?g/kg·h,lasting 1h,in group J.The collapsed lung was preserved for detection.ABP,HR,Pairway and arterial blood gas analysis were recorded at three time points,which were 30 min before OLV?T₁?,30 min after OLV?T₂?and 30 min after TLV?T₃?.Then wet and dry weight ratio was measured after non-ventilatory lung was processed and preserved.The microstructure changes of collapsed lung tissue were observed by hematoxylon-eosin?HE?staining and transmission electron microscopy.Results The changes of HR and MAP in the five groups were not statistically significant.Pairway was significantly increased in OLV,and it was restored after recovery of the lungs,but still higher than that of T₁.In regard to SaO₂ and Pa O2,the C and J groups were significantly lower than group S at T₂ and T₃.There was significant difference between group N and the C and J groups at T₂ and T₃?P<0.01?.In respects of W/D of collapsed lung,the other four groups had significant difference compared with group S.The W/D of group N decreased significantly compared with that of group C?P<0.01?.The W/D of group J increased significantly compared with that of group N?P<0.05?.In HE staining pictures,the alveolar structure damage is serious in C and J groups.Partial alveolar wall collapsed and disappeared.There was congestion,red blood cells and inflammatory cells in lung tissue.The alveolar wall became thick owing to edema,serous effusion,and the formation of transparent membrane.It was improved in group N,similar to that in group S,which was close to normal as a result.Breathing membrane is thin without hemorrhage,inflammatory cells and edema.Group D was between N and C groups,and the effect of group N was partially reversed by glibenclamide,close to that of group C.In electron microscopy pictures,there was nucleus pycnosis,lobulated state,gap surrounding nuclear widened in three kinds of cells in C and J groups.There was lamellar corpuscle emptying,microvilli on the cell membrane thinner and reducing in? type epithelial cells.It was improved in group N,similar to that in group S,which was close to normal as a result.Group D was between N and C groups,and the effect of group N was partially reversed by glibenclamide,close to that of group C.Conclusion Nicorandil,related to its dosage,has a protective effect on the collapse and inflation of non-ventilatory lung in rabbit OLV model,improving morphology and life indexes and dramatically reducing the incidence of hypoxemia.Objective To investigate the effects and mechanisms of nicorandil on lung injury of the collapsed lung in rabbit OLV model.Methods Thirty clean rabbits were randomly divided into sham group?group S??two-lung ventilation+thoracotomy?,negative control group?group C??one-lung ventilation+thoracotomy+saline?,nicorandil group?group N??one-lung ventilation+thoracotomy+nicorandil?and antagonist group?group J??one-lung ventilation+thoracotomy+ nicorandil +glibenclamide?equally.Nicorandil was infused by 100?g/kg·h,lasting 1h,in group N.Nicorandil was infused by 50?g/kg·h,lasting 1h,in group D.The same volume saline was infused in S and C groups.Nicorandil was infused by 100?g/kg·h with glibenclamide by 75?g/kg·h,lasting 1h,in group J.The collapsed lung was preservation for detection.MDA,TNF alpha and SOD activity were measured by ELISA to find the changes of inflammatory mediators and oxidative stress.The apoptosis of lung tissue was observed by TUNEL.The changes of PI3 K,Akt,p-Akt,NF-kappa B and HIF-1alpha protein were detected by Western blot in order to find molecular signaling pathways.The HIF-1alpha m RNA of lung was detected by qRT-PCR.The changes of Bax,Bcl₂ and Caspase-3 protein were detected by Western blot in order to find downstream genes related to apoptosis.Results In respects of MDA of collapsed lung,the other four groups had significant difference compared with group S?P<0.05?.The MDA of group N decreased significantly compared with that of group C?P<0.01?.The MDA of group J increased significantly compared with that of group N?P<0.01?.The MDA of group D also decreased significantly compared with that of group C?P<0.01?.The MDA of group J increased significantly compared with that of group D?P<0.05?.The trendency of TNF alpha was same to MDA,while that of SOD activity was opposite to MDA.In fluorescence microscope pictures by TUNEL,there were many apoptotic cells in C and J groups,similar to the positive control group with high apoptosis index.Group N had obvious changes,was similar to the S group.There were only a few apoptotic cells in normal circumstances.This situation was reversed after the use of glibenclamide,so there were more apoptosis cells in group J.Group D also had obvious increase in the number of apoptotic cells,similar to group J.In view of PI3 K,group N increased significantly compared with group C?P<0.01?,while group N increased significantly compared with group J?P<0.01?.In terms of p-Akt protein expression and p-Akt/Akt,N and D groups increased significantly compared with group C?P<0.01?.N and D groups also increased significantly compared with group J?P<0.01?.In respects of NF-kappa B,group C increased significantly compared with group S?P<0.05?.Group N decreased significantly compared with group C?P<0.01?,while group J increased significantly compared with group N?P<0.01?.There was significantly difference between group J and group C?P<0.05?.In terms of HIF-1alpha protein and m RNA,N and D groups increased significantly compared with group C?P<0.01?,while group J decreased significantly compared with N and D groups?P<0.01?.There was significantly difference between group J and group C?P<0.05?.In terms of Bax and Caspase-3,group N decreased significantly compared with group C?P<0.01?,while group J increased significantly compared with group N?P<0.01?.Group D also decreased significantly compared with group C?P<0.05?.The trendency of Bcl₂ was opposite to that of Bax.Conclusion Nicorandil,related to its dosage,has a protective effect on the collapse and inflation of non-ventilatory lung in rabbit OLV model,dramatically reducing the incidence of apoptosis.It acts on the mito KATP,through PI3K/Akt signaling pathway,decreasing the expression of NF-kappa B,increasing the expression of HIF-1alpha,and reducing oxidative stress,pulmonary edema,accumulation of inflammatory factors and the lung injury caused by IR.It also regulates the expression of downstream Bax and Bcl₂ genes,regulates apoptosis by Bax/Bcl₂,and reduces apoptosis by decreasing the expression of Caspase-3,a kind of main execution protein related to apoptosis.Objective To investigate the effects of nicorandil on lung injury of the collapsed lung in clinical thoracic surgery.Methods 60 cases of ASA ?-? elective patients with lung cancer radical,were randomly divided into sham group?group S?,control group?group C?and nicorandil group?group N?,containing 20 cases in each group and containing 30 men and 30 women in the research.Patients' brain,liver,kidney,lung and biochemical examination were normal,while EKG had ST-T changes,indicating myocardial ischemia.Patients with history of peptic ulcer and sulfonamide drug allergy were ruled out.ABP,HR,Sp O2,and arterial blood gas analysis were recorded at four time points,which were before the use of nicorandil?T₁?,30 min after OLV?T₂?,30 min after TLV?T₃?and 30 min after extubation?T₄?.Pairway was recorded at T₂ and T₃.Surgical specimens in vitro were cutted at the edge of it about 1*1*1cm3.HE staining and transmission electron microscope pictures were obsreved.The apoptosis of the lung tissue specimens were observed by TUNEL.Results The results of gender,age,height,weight,disease,ASA classification and operation time had no statistical difference in three groups.HR and MAP fluctuated in physical range and had no statistical difference from T₁ to T₄ in three groups.In terms of Pairway,group N is better than that of group C at T₂ and T₃,but had no statistical difference.SaO₂ and Pa O2 were observed by blood gas analysis.Group N is better than that of group C At T₂ and T₄?P<0.01?.Pa O2 fell owing to no pure oxygen inhalation at T₄.The trendency of Sp O2 were the same to SaO₂.In respects of HE staining and electron microscopic structures,group N is better than that of group C.In HE staining pictures,the alveolar structure damage is serious in group C.Partial alveolar wall collapsed and disappeared.There was congestion,red blood cells and inflammatory cells in lung tissue.The alveolar wall became thick owing to edema,serous effusion,and the formation of transparent membrane.It was improved in group N,similar to that in group S,which was close to normal as a result.Breathing membrane is thin without hemorrhage,inflammatory cells and edema.In electron microscopy pictures,there was nucleus pycnosis,lobulated state,gap surrounding nuclear widened in three kinds of cells in group C.There was lamellar corpuscle emptying,microvilli on the cell membrane thinner and reducing in? type epithelial cells.It was improved in group N,similar to that in group S,which was close to normal as a result.In fluorescence microscope pictures by TUNEL,there were many apoptotic cells in group C,similar to the positive control group with high apoptosis index.Group N had obvious changes,was similar to the S group.There were only a few apoptotic cells in normal circumstances.Conclusion Nicorandil has a protective effect on the collapse and inflation of nonventilatory lung in clinical,improving morphology and life indexes and dramatically reducing the incidence of hypoxemia and apoptosis.It also plays a role on lung protection by reducing IR injury.