The Experimental Study Of CPAP On The Non-ventilated Side To Alleviate Acute Lung Injury During One-lung

Non-physiological one-lung ventilation(OLV)is the main cause of acute lung injury(ALI)after thoracic surgery.Studies have shown that non-ventilated lung hypoxia/ischemia,reoxygenation/reperfusion-induced inflammation and oxidative stress play an important role during OLV.Drugs have been used in animal and clinical studies both at home and abroad,but the results are different.Heme oxidase-1(HO-1)is a kind of initial enzyme and rate-limiting enzyme.It has many physiological regulation functions,such as antioxidant,anti-inflammatory,anti-apoptotic and cell protection.It is the most important endogenous protective protein in the body.We hypothesized that non-drug intervention with 2-5 cmH2O continuous positive airway pressure(CPAP)on non-ventilated lung in rabbit OLV model could not only reduce hypoxia caused by collapsed alveolar dilatation,reduce blood shunt to ventilated side caused by hypoxic pulmonary vasoconstriction,but also alleviate ischemia-reperfusion injury caused by pulmonary reoxygenation(reoxygenation/reperfusion);at the same time,we expected that CPAP could induce the increase of HO-1 gene expression and NF-kappaB M Decreased RNA expression produces significant anti-ischemia-reperfusion injury,anti-oxidation,anti-inflammatory response and anti-apoptosis,thus exerting lung protection during OLV.Objective:To observe the lung protective effect of continuous positive airway pressure(CPAP)with 2 or 5 cmH2O on non-ventilated lung during one-lung ventilation in rabbits,and to detect the expression of HO-1 and NF-kappa B,and to explore the possible protective mechanism of CPAP on non-ventilated lung during OLV.Methods:Twenty-four healthy male New Zealand white rabbits were randomly divided into three groups(n=8):control group(group D),non-ventilated side CPAP 2cmH 2(group M),non-ventilated side CPAP 5cmH 2(group H).After 3%pentobarbital sodium(1ml/kg)was injected into the ear vein of rabbits,the limbs were fixed in supine position.The left femoral artery and the right femoral vein were separated for catheterization.The left femoral artery catheterization was used for ECG,blood pressure monitoring and blood gas analysis.The right femoral vein catheterization was used for intraoperative fluid supplementation and administration.Tracheotomy was performed under local anesthesia.Vecuronium(0.1 mg/kg),a muscle relaxant,was injected into the femoral vein,and a self-made continuous positive pressure ventilation double-lumen tracheal tube was inserted for mechanical ventilation.Group D received bilateral lung ventilation for 30 minutes,right lung ventilation for 180 minutes,and bilateral lung ventilation for 60 minutes.Group M and Group H received bilateral lung ventilation for 30 minutes,while right lung ventilation for]80 minutes,continuous positive pressure ventilation was applied to collapsed lung(left lung)under the pressure of 2 and 5 cmH2O,respectively,and bilateral lung ventilation lastly for 60 minutes.Three groups of ventilation parameters were set:FiO2 0.21,VT 12 ml/kg,respiratory frequency 40 times/min,I:E=1:2.Arterial blood was collected at the beginning of ventilation(T0),60 minutes of one-lung ventilation(T1)and 30 minutes before the end of ventilation(T2)for blood gas analysis.After ventilation,the left and right bronchus were separated for bilateral lung lavage,then the bilateral lung lavage fluid was preserved.IL-6,IL-10 and TNF-alpha in bilateral lung lavage fluid were detected by ELISA.The left upper lobe was fixed,paraffin-embedded,sliced and HE stained,and the degree of lung injury was observed under fibroscope.The left upper lobe lung tissue was frozen at 0.1 g,-80 C.The contents of NO,MDA and SOD were detected.Two upper lobes of the left lung were frozen at-80?,one was detected by Q-PCR for HO-1 and NF-kappa B,and one was detected by WB for HO-1,NF-kappa B and Caspase-3.Then the lower lobes of the left lung were taken for wet/dry weight ratio detection.Results:1.Oxygenation index(OI)changes:compared with T0,OI decreased significantly at T1 and T2 in the three groups(P<0.01);compared with group D,OI increased significantly at T1 and T2 in group M(P<0.01);compared with group M,OI increased not significantly at Ti and T2 in group H(P>0.05).2.Changes of inflammatory reaction factors:Compared with group D,the levels of IL-6 and TNF-alpha in both lungs of group M and H were significantly lower(P<0.01),and the levels of IL-10 in group H were significantly lower than those in group M(P<0.01);compared with group D,the levels of IL-10 in both lungs of group M and H were significantly higher(P<0.01),and the levels of IL-10 in group H were significantly higher than those in group M(P<0.01).3.Change of redox reaction index:Compared with group D,NO and MDA in lung tissue of non-ventilated side of CPAP in group M and H decreased significantly(P<0.01),and SOD level in group H decreased more significantly(P<0.01),SOD level in group M and H increased significantly(P<0.01),and SOD level in group H increased more significantly(P<0.01)than that in group M.4.Caspase-3 protein expression:Compared with group D,the expression of Caspase-3 protein in non-ventilated lung tissue of group M and H using CPAP was significantly lower(P<0.01),and the expression of Caspase-3 protein in group H was significantly lower than that in group M(P<0.01).5.Expression of HO-1,NF-kappa B and HO-1 and NF-kappa B:Compared with group D,the expression of NF-kappa B and NF-kappa B in lung tissue of non-ventilated side of CPAP in group M and H decreased significantly(P<0.01),and the expression of HO-1 and HO-1 in group M and H increased significantly(P<0.01),and the expression of HO-1 in group H was higher than that in group M(P<0.01).6.Lung injury score:CPAP non-ventilated lung tissue injury score was used in group D 6.25±1.76,group M 4.57±1.69 and group H 4.62±1.74.Compared with group D,the scores of lung injury in group M and H were significantly lower(P<0.01),while those in group H were slightly higher than those in group M,but there was no significant difference between the two groups(P>0.05)7.Wet/dry weight ratio of lung tissues:The wet/dry weight ratio of lung tissues on non-ventilated side of CPAP was 5.25±1.43 in group D,4.77±1.58 in group M and 4.62 ± 1.74 in group H.Compared with group D,the wet/dry weight ratio of lung tissue in group M and H was significantly lower(P<0.01);compared with group M,the score in group H was slightly lower,but there was no significant difference between the two groups(P>0.05).Conclusion(s):1.Continuous positive airway pressure(CPAP)ventilation on the non-ventilated side of the lungs during one-lung ventilation in rabbits can improve oxygenation,produce anti-inflammatory,anti-oxidative and anti-apoptotic effects and exert lung protection.2.The mechanism of non-ventilated continuous positive airway pressure(CPAP)ventilation during one-lung ventilation to alleviate acute lung injury in rabbits may be to induce up-regulation of HO-1 expression and down-regulation of NF-kappa B expression.