摘要
目的探讨控制性机械通气（CMV）对大鼠膈肌功能的影响，了解不适当控制性机械通气与膈肌功能不全和脱机困难的关系。方法将24只雄性SD大鼠按随机数字表法分为3组：正常对照组、18hCMV组和24hCMV组。后两组分别给予18h和24hCMV，并测定膈肌跨膈压（Pdi）、最大跨膈压（Pdimax）、膈肌肌电图（EMGdi）等指标和膈肌肌球蛋白重链（MHC）表型的改变。两样本组间均数比较用t检验，多组问均数差异性比较采用单因素方差分析。结果与对照组比较，18、24hCMV组Pdimax分别为[（8．98±0．55、6．12±0．53、14．92±0．16）cmH20，1cmH20=0．098kPa]，实验组均低于对照组，差异有统计学意义（F=82．35，P〈0．01）；实验组EMGdi的中心频率和高低频比值均低于对照组；在最大刺激频率（100Hz）下18、24hCMV组的膈肌肌张力[（84．114±0．43、52．65±0．64）N]较对照组[（98．13±0．50）N]低，差异有统计学意义（F=15．02，P〈0．01）；同时MHC2。比例下降；24hCMV组大鼠膈肌肌纤维的电镜下病理改变为：膈肌出现肌原纤维排列疏松、脂肪滴和空泡增多，个别出现线粒体肿胀、空化，嵴减少。结论短期CMV即可导致膈肌功能失调和形态改变；机械通气，特别是CMV诱导的膈肌功能障碍可能是引起临床上一些患者脱机困难的重要原因之一。
Objective To investigate the effect of controlled mechanical ventilation （CMV） on the diaphragm of rats, and therefore to understand the theoretic basis of difficulty weaning due to dysfunction and morphology in diaphragm induced by inappropriate mechanical ventilation. Methods Twenty-four adult male SD rats were randomly assigned into 3 experimental groups： a control group, a 18 h CMV group, and a 24 h CMV group. Trans-diaphragmatic pressure （ Pdi ）, maximal trans-diaphragmatic pressure （ Pdimax）,diaphragm electromyogram （EMGdi）, and diaphragm muscle force were measured during CMV at various stimulation frequencies. Morphological changes of the diaphragm myofibril were observed by transmission electron microscopy. Myosin heavy chain（MHC） isofonn expression were analyzed with SDS-glycerol PAGE and Western blotting. Results The Pdimax in the 18 h CMV group and the 24 h CMV group [ （8. 98 ± 0. 55, 6. 12 ± 0. 53 ） cm H2O, 1 cm H2O = 0. 098 kPa ] was significantly reduced （ F = 82. 35, P 〈 0. 01 ）compared with the control group L （14. 92±0. 16）cm H2O ]. The Fc and the H/L decreased significantly. At the stimulation frequency of 100 Hz, the diaphragm muscle force in the 18 h CMV group and 24 h CMV group [ （84. 11 ±0.43）N, （52. 65±0. 64）N, respectively] decreased compare with the control[ （98. 13 ±0. 50）N, F = 15.02, P 〈 0.01 ]. The proportion of MHC2A decreased in the 24 h group compared with control. The uhrastructural changes of the diaphragm was observed in the 24 h CMV group, such as disrupted myofibrils, increased numbers of lipid vacuoles in the sarcoplasm, and abnormally small mitochondria containing focal membrane disruptions. Conclusion Short-term CMV induced diaphragm fatigue and altered the function and morphology of diaphragm in SD rats. Diaphragmatic dysfunction induced by CMV maybe one of the important reasons for difficult weaning.
出处
《中华结核和呼吸杂志》
CAS
CSCD
北大核心
2009年第2期103-106,共4页
Chinese Journal of Tuberculosis and Respiratory Diseases
关键词
呼吸
人工
膈
肌球蛋白重链
Respiration, Artificial
Diaphragm
Myofibril damage
Myosin heavy chain
