Mucociliary transport in the respiratory epithelium depends on beating of cilia to move a mucus layer containing trapped inhaled particles towards the mouth. Little is known about the relationship between cilia beat frequency (CBF) and mucus transport velocity (MTV) in vivo under normal physiological conditions and when inspired air is dry or not fully humidified. This study was designed to use video-microscopy to simultaneously measure CBF and MTV in the tracheal epithelium through an implanted optical window in mechanically ventilated lambs. The inspired air in 6 animals was heated to body temperature and fully saturated with water for 4 hours as a baseline. In another series of experiments, 5 lambs were ventilated with air at different temperatures and humidities while the mucosal surface temperature was also monitored with infrared macro-imaging. In the baseline experiments during ventilation with fully humidified air at body temperature CBF remained fairly constant, mean 13.9±1.6Hz but MTV varied considerably between 0.1 and 26.1mm/min with mean 11.0±3.9mm/min, resulting in a maximum mucus displacement of 34.2µm/cilia beat. Fully humidified air at body temperature prevented fluctuations in the surface temperature during breathing indicating a thermodynamic balance in the airways. When lambs were ventilated with dryer air, the mucosal surface temperature and MTV dropped without a significant change in CBF. When inspired air was dry, mainly latent heat (92%) was transferred to air in the trachea, reducing the surface temperature by 5°C. Reduced humidity of the inspired air lowered the surface temperature and reduced MTV in the epithelium during ventilation.

中文翻译：

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气管粘膜纤毛运输的可变性不受在加湿和未加湿空气通风期间体内打败羔羊纤毛的控制

呼吸道上皮中的粘膜纤毛转运依赖于纤毛的跳动，以将包含捕获的吸入颗粒的粘液层移向口腔。在正常生理条件下以及吸入的空气干燥或未充分加湿时，体内纤毛搏动频率（CBF）与粘液运输速度（MTV）之间的关系鲜为人知。这项研究旨在使用视频显微镜通过机械通风的羔羊中植入的光学窗口同时测量气管上皮中的CBF和MTV。将6只动物的吸入空气加热至体温，并以水完全饱和4小时作为基线。在另一系列的实验中 用不同温度和湿度的空气对5只羊羔进行通风，同时还通过红外宏观成像监测粘膜表面温度。在人体温度为CBF的完全湿润空气通风期间的基线实验中，CBF保持相当恒定，平均值为13.9±1.6Hz，但MTV在0.1至26.1mm / min之间变化很大，平均值为11.0±3.9mm / min，导致最大的粘液位移为34.2µm /纤毛搏动。在人体温度下完全湿润的空气可防止呼吸过程中表面温度的波动，从而表明呼吸道的热力学平衡。当羔羊用干燥机通风时，粘膜表面温度和MTV下降，而CBF没有明显变化。吸入的空气干燥后，主要潜热（92％）转移到气管中的空气中，将表面温度降低5°C。通风过程中，吸入空气湿度的降低降低了表面温度并降低了上皮的MTV。