慢性阻塞性肺疾病模型大鼠膈肌功能的实验研究

Experimental study on diaphragmatic function in rats with chronic obstructive pulmonary disease

目的以慢性阻塞性肺疾病（chronic obstructive pulmonary disease，COPD）模型大鼠为研究对象，探讨膈肌功能及短期控制性机械通气对膈肌功能的影响。方法应用气管内滴注脂多糖联合被动吸烟的方法复制大鼠COPD模型，比较正常大鼠与COPD大鼠跨膈压及膈肌肌电图频谱变化；对COPD模型组大鼠行短期控制机械通气，观察其膈肌功能的变化。结果COPD模型组大鼠肺功能与正常对照组比较FEV0．3／FVC[（88．05±5．87）％VS（69．41±11．50）％]显著下降（P〈0．05）。COPD模型组大鼠跨膈压与正常对照组相比[（4．28±1．03）cm H2O vs（5．36±0．94）cm H2O]显著下降（P〈0．05），说明COPD模型组大鼠呼吸肌力较正常对照组下降。COPD模型组大鼠较正常对照组大鼠的膈肌肌电高低频比值（％）（4．99±2．36vs3．12±1．10）下降显著（P〈0．05），低频部分显著增加（P〈0．05）。COPD模型组大鼠机械通气（6h）前后跨膈压及肌电图频谱分析结果差异无统计学意义。结论COPD模型组大鼠跨膈压较对照组减小，膈肌肌电图频谱分析高低频比值下降，说明其膈肌功能下降。短期（6h）控制机械通气对COPD大鼠膈肌功能无显著影响。

Objective To explore diaphragmatic function and the influence of controlled mechanical ventilation on diaphragmatic function in chronic obstructive pulmonary disease（COPD） model rats. Methods Dripping lipopolysaccharide applied to trachea and passive smoking were applied to replicate the model of COPD; the changes of trans-diaphragmatic ,pressure and spectrum analysis of electromyogram of diaphragmatic muscle in normal rats and COPD rats were compared; the effect of short term controlled mechanical ventilation on diaphragmatic function of COPD rats was observed. Results FEV0.3/FVC decreased in rats in model group compared with that in normal group （88.05±5.87）% vs （69.41 ±11.50）% （P 〈0.05）. The transdiaphragmatic pressure of model group was lower than that of control group （4.28±1.03） cmH2O vs （5.36±0.94） cm H2O （P 〈0.05）. Results of spectral analysis of electromyographic signal of diaphragmatic muscle in ratio by high frequency and low frequency were lower in model group than those in control group （P 〈 0.05）. However, it was increased significantly in low frequency in model group. Results of trans-diaphragmatic pressure and spectrum analysis of electromyographic signal of diaphragmatic muscle before and after mechanical ventilation in rats of COPD model were of no significant difference （ P 〈 0.05）. Conclusions By trans-diaphragmatic pressure and spectrum analysis of electromyographic signal of diaphragmatic muscle measuring, it is indicated that diaphragmatic function decreases in rats with COPD. Short term （6 hours controlled mechanical ventilation has no significant effect on diaphragmatic function in rats with COPD.