Objective To observe the changes in the transforming growth factor-beta 1 (TGF-β1 ) mRNA expression in the lung in a dog model of cardiopulmonary bypass(CPB)-induced acute lung injury. Methods Thirty-six healthy adult mongrel dogs of both sexes weighing 15-16 kg were randomly assigned into control group and CPB group ( n = 18 each) . Lung injury was produced by CPB according to the method described by Williams. Six animals were killed at each of the following time points: before CPB (T0 ) and 30 and 60 min after termination of CPB (T1 , T2) in each group. Lung specimens were obtained for microscopic examination and determination of TGF-β1 mRNA expression (by RT-PCR) and MDA content. The lungs were lavaged and the protein concentration in the brancho-alveolar lavage fluid (BALF) was determined and pulmonary permeability index (PPI) was calculated. Results Microscopic examination showed massive inflammatory cell infiltration, alveolar capillary dilatation, congestion, widened alveolar septum, massive RBC in the alveolar space and focal atelectasis in the lung in CPB group. The TGF-β1 mRNA expression and MDA content and PPI were significantly higher in CPB group than in control group. The TGF-β1 mRNA expression and MDA was positively correlated to PPI (MDA: r = 0.867, P < 0.01; PPI: r = 0.821, P < 0.01) . Conclusion TGF-β1 mRNA expression in the lung is significantly up-regulated after CPB and is an important factor contributing to CPB-induced acute lung injury.

ObjectiveTo investigate the effect of N-acetylcysteine on lung injury induced by cardiopulmonary bypass(CPB) in dogs.MethodsThirty-six healthy adult mongrel dogs of both sexes weighing 15-16 kg were randomly assigned into 2 groups (n =18 each):CPB group (group C) and N-acetylcysteine group(group N).Lung injury was produced by CPB.In group N N-acetylcysteine 150 mg/kg was injected iv immediately before CPB,followed by infusion at 20 mg· kg-1 · h-1 until 60 min after termination of CPB.Blood samples were taken from femoral artery before CPB (T0,baseline),30 and 60 min after termination of CPB (T1,T2 ).Oxygenation index ( OI =PaO2 ÷ FiO2 ) and respiratory index (RI =PA-(a) DO2 ÷ PaO2 ) were calculated.Six animals were sacrificed at each time point.Lung specimens were obtained for microscopic examination,and determination of transforming growth factor-β1 (TGF-β1) mRNA expression,MDA content and SOD activity.ResultsCPB significantly increased RI,MDA content and TGF-β1 mRNA expression and decreased OI and SOD activity at T1 and T2 as compared with the baseline values at T0 in group C.N-acetylcysteine administered before and during CPB significantly attenuated CPB-induced above changes in OI,RI,MDA content,SOD activity and TGF-β1 mRNA expression.Microscopic examination showed that N-acetylcysteine significantly ameriorated CPB-induced lung damage.ConclusionsN-acetylcysteine administered before and during CPB can attenuate CPB-induced lung injury by inhibiting lipid peroxidation response and down-regulating TGF-β1 expression.

Animals ; Metabolic Syndrome/therapy* ; Probiotics/therapeutic use* ; Models, Animal