呼吸机机械通气对兔气道黏蛋白表达的影响

Effects of mechanical ventilation by breathing machine on the expression of MUC5AC in rabbits

目的观察呼吸机机械通气对黏蛋白(MUC5AC)表达的影响,并对其机制进行初步探讨。方法日本大耳兔随机分为对照组、机械通气1、3、6、12和24 h组以及2、5和10 cm H2O呼气末正压(PEEP)组。取支气管肺泡灌洗液(BALF),用ELISA和RT-PCR法检测BALF中肿瘤坏死因子(TNF)-α、白介素(IL)-8、MUC5AC蛋白和mRNA的水平,计数BALF中多型核粒细胞,底物检测法测定中性粒细胞弹力酶(NE)活性。结果机械通气能显著增强MUC5AC的分泌(P<0.05)。通气3 h TNF-α表达至峰值,随后逐渐下降(P<0.05)。通气6 h IL-8表达至峰值,随后逐渐下降(P<0.05)。通气12 h后多型核粒细胞数及中性粒细胞弹力酶活性显著升高,24 h后回降(P<0.05)。随着PEEP的增加,TNF-α、IL-8、MUC5AC mRNA的表达和蛋白含量、多型核粒细胞数和NE活性均随之升高(P<0.05)。结论机械通气能促进气道黏膜上皮细胞分泌MUC5AC,其机制可能与机械通气引发炎性反应有关。

Objective To study the effect of mechanical ventilation on the expression of MUC5AC and investigation for mechanism. Methods Rabbits were divide into control group and test groups including one, three, six, twelve, twenty-four hour mechanical ventilation and 2, 5, 10 cm H2O PEEP mechanical ventilation pressure. Contents of TNF-α, IL-8, MUC5AC mRNA and protein in bronchoalveolar lavage fluid were determined by RT-PCR and ELISA methods, respectively. Neutrophils in bronchoalveolar lavage fluid were counted. Neutrophil elastase activity was measured by assays of substrate. Results Mechanical ventilation increased expression of MUC5AC in bronehiorum endothelial eells（P 〈 0. 05 ）. After mechanical ventilation for three hours, the expression of TNF-α reached the peak （P 〈 0. 05 ）. The expression of IL-8 reached the peak after six hours （ P 〈 0. 05 ）. Neutrophil eount and neutrophil elastase activity reached the peak after twelve hours （P 〈 0. 05 ）. With the increase of PEEP,the mRNA and protein of TNF-α, IL-8, MUC5AC, the number of PMN and neutrophil elastase activity was also increased （P 〈 0. 05 ）. Conclusion Mechanical ventilation may increase the expression of MUC5AC in bronchiorum endothelial ceils. This maybe is concerned with inflammation.