不同潮气量通气对内毒素肺损伤大鼠Th1/Th2淋巴细胞平衡的影响

Influence of mechanical ventilation with different tidal volume on Th1 / Th2 lymphocyte balance in rats with endotoxin induced acute lung injury

目的:探讨不同潮气量通气对内毒素肺损伤大鼠Th1/Th2淋巴细胞平衡的影响。方法:健康大鼠32只,随机分成4组:生理盐水正常对照组(A组)、内毒素肺损伤非机械通气组(B组)、内毒素肺损伤+小潮气量组(C组)、内毒素肺损伤+传统潮气量组(D组)。监测平均动脉压(MAP)、心率(HR),计算氧合指数(OI),检测外周血单核细胞(PBMC)中IFN-γ、IL-4浓度并计算IFN-γ/IL-4。取右肺中叶计算肺组织湿干比值(W/D);观察右肺下叶肺组织病理变化;分析支气管肺泡灌洗液(BALF)中白细胞(WBC)与中性粒细胞(PMN)计数。结果:B、C、D组OI、W/D及病理学变化符合急性肺损伤表现。B组IFN-γ/IL-4比值、肺W/D及BALF中WBC、PMN计数明显高于A组与C组,但低于D组。结论:①注射内毒素可成功复制大鼠急性肺损伤动物模型;②内毒素致大鼠肺损伤早期,其PBMC中IFN-γ和IL-4浓度增加,IFN-γ/IL-4比值升高,Th1/Th2淋巴细胞失衡;③传统潮气量机械通气可加重内毒素肺损伤大鼠炎症反应,使肺损伤早期大鼠Th1/Th2淋巴细胞失衡加剧;④保护性通气策略的小潮气量机械通气可减轻内毒素肺损伤大鼠PMN在肺内"扣押",改善Th1/Th2淋巴细胞失衡状态。

Objective：To investigate the influence of mechanical ventilation with different tidal volume on Th1 /Th2 balance in rats with endotoxin induced acute lung injury（ALI）.Methods：Thirty-two healthy adult SD rats were randomly divided into four groups：normal sodium control group（group A）,endotoxin induced acute lung injury without mechanical ventilation group（group B）,endotoxin induced acute lung injury with small tidal volume ventilation group（group C） and endotoxin induced acute lung injury with traditional tidal volume ventilation group（group D）.The mean arterial pressure,heart rate were mornitored,oxygenation index（OI） was calculated.The concentrations of IFN-γ and IL-4 of peripheral blood mononuclear cell（PBMC） were detected and the ratio of IFN-γ/IL-4 was calculated.The right lung median lobe was obtained to calculate W/D,and pathological changes of lung tissue from inferior lobe of right lung was observed.White blood cell count（WBC） and polymorphonuclear neutrophils（PMN） in the bronchoalvedar lavage fluid（BALF） were analyzed.Results：OI,W/D and pathological changes were accorded with acute lung injury in group B,C and D.IFN-γ/IL-4,lung W/D and the WBC,PMN in BALF was significantly higher in group B than those in group A and C,but lower than that in group D.Conclusions：① Injection of endotoxin in rats can successfully reproduced animal models of ALI.②Concentrations of IFN-γ and IL-4 in PBMC,IFN-γ/IL-4 ratio increased in the early stage of ALI rats induced by endotoxin,so with Th1/Th2 lymphocyte imbalances.③Mechanical ventilation with traditional tidal volume can exacerbate lung injury in the rats induced by endotoxin during inflammatory response,so that aggravate Th1/Th2 lymphocyte imbalances of the early lung injury in rats.④Mechanical ventilation with small tidal volume as a protective ventilation strategy of endotoxin lung injury in rats can lighten the PMN to keep in the lung,thus may correct the Th1 /Th2 lymphocyte imbalance.