节律性压力波对家犬气道黏蛋白分泌平衡的影响及其机制

Effect of rhythmic pressure waves on balancing airway basic mucus secretion in dogs

目的:观察不同压力对家犬气道黏液层黏蛋白(MUC)分泌的影响,并初步探讨其参与机制。方法:24只健康家犬行双腔支气管导管插管,并随机分为4组(n=6)。A组家犬正常呼吸的频率及压力双侧通气(A1,A2);B组一侧不通气(B1),另一侧予以过量通气(B2);C组预先张力敏感性阳离子通道4(TRPV4)阻断剂钉红(RR)后按A组通气模式通气(C1,C2);D组预先TRPV4阻断剂RR处理后按B组通气模式通气(D1,D2)。通气12 h后,ELISA检测3组支气管灌洗液(BALF)中MUC(2,5AC和5B)蛋白含量;RT-PCR检测支气管肺组织匀浆中MUC(2,5AC和5B)mRNA转录水平。结果:与正常通气的A2组比较,过量通气的B2组家犬BALF中3种MUC蛋白含量显著升高,且以MUC5AC为主(P<0.05);与A1组比较,未通气的B1组则明显下降(P<0.05)。与A1,A2组比较,给予RR处理后的C1,C2组蛋白含量均明显降低(P<0.05)。与过量通气的B2组比较,给予TRPV4特异性阻断剂处理后再过量通气的D2组3种MUC蛋白含量亦明显下降(P<0.05)。与A2组比较过量通气的B2组肺组织MUC(2,5AC和5B)mRNA表达均明显上调(P<0.05);与A1,A2比较,给予RR处理后C1,C2组肺组织3种MUC mRNA转录水平显著下降(P<0.05);给予RR预处理后与B2组相比,D2组内MUC mRNA转录水平显著下调(P<0.05)。结论:节律性压力波参与维持家犬气道上皮黏液层黏蛋白分泌平衡调控,其机制主要通过TRPV4通道实现。

Objective： To investigate the effect of different pressure on mucin （MUC） secretion in dog airway mucus layer and explore the participation mechanisms. Methods： Totally 24 healthy dogs were randomly divided into 4 groups （n=6） after double-lumen endobronchial tube intubation. In group A the dogs were ventilated bilaterally with normal breathing frequency and pressure; In group B： one side of the dog lung did not ventilate, while the other side was excessively ventilated. In group C： the tension-sensitive cation channel （TRPV） 4 blocker Ruthenium Red （RR） was injected in advance, and ventilated as in group A. In group D： TRPV4 blocker RR was injected firstly, and then ventilated as in group B. After 12 h ventilation, we collected bronchoalveolar lavage fluid （BALF）, tested MUC （2, 5AC, 5B） protein content by ELISA, and detected the transcription of MUC （2, SAC, 5B） mRNA of bronchial lung tissue by RT- PCR. Results： Compared with the normal ventilation （A2） group, the protein level of MUC of excessive ventilation （B2） group was significantly higher, mainly MUCSAC （P〈0.05）; compared with the normal ventilation （A1） group, the protein level of MUC of no ventilation （B 1） group was significantly decreased （P〈0.05）. After pretreatment with RR, the MUC protein level of group C1, C2 were significantly lower than that of group A1, A2 （P〈0.05）; the MUC protein level of group B2were significantly lower than that of group D2 （P〈0.05）. The MUC （2, SAC and 5B） mRNA level was higher in excessive ventilation group （B2） than in normal ventilation group （A2）. After pretreatment with RR, in comparison with group A1, A2, the MUC （2, SAC and 5B） mRNA level of group C 1, C2 declined; in comparison with group B2, the MUC （2, SAC and 5B） mRNA level of group D2 declined. Conclusion： Rhythmic pressure waves may regulate and balance basic airway mucin secretion through activating the TRPV4 channel in dogs.