吸气肌训练对呼吸机相关性膈肌功能障碍大鼠膈肌的影响及机制研究

关键词：呼吸机相关性膈肌功能障碍  吸气肌训练  机械通气  钙蛋白酶  氧化应激

Keywords:ventilator induced diaphragmatic dysfunction  inspiratory muscle training  mechanical ventilation  calpain  oxidative stress

摘要：

      摘要 目的：观察吸气肌训练对呼吸机相关性膈肌功能障碍（ventilator induced diaphragmatic dysfunction， VIDD）大鼠膈肌形态及功能的影响，探讨吸气肌训练对VIDD大鼠膈肌影响的机制。 方法：将SD大鼠随机分为4组：①对照组（n=6）；②通气组（n=6）：机械通气24h；③假训练组（n=6）：机械通气24h后进行1h自主呼吸；④训练组（n=6）：机械通气24h后进行1h间歇性吸气肌训练。采用生物信号采集系统测量膈肌单收缩力、最大强直收缩力、张力-频率曲线；HE染色测量膈肌纤维横截面积；Western Blot检测膈肌中微管相关蛋白轻链 3（micro-tubule-associated protein 1 light chain 3， LC3）、肌萎缩相关蛋白（muscle atrophy F-box， MAFbx）的表达水平。采用ELISA法检测膈肌中αⅡ血影蛋白裂解产物（αⅡ-spectrin breakdown products， SBDPs）SBDP145与SBDP120水平；用硫代巴比妥酸（thiobarbituric acid， TBA）法测定膈肌中丙二醛（malondialdehyde， MDA）水平。 结果：与对照组和训练组相比，通气组和假训练组膈肌单收缩力、最大强直收缩力、张力-频率曲线明显下降（P＜0.05），通气组和假训练组无差异；对照组和训练组无差异。与对照组相比，通气组、假训练组、训练组膈肌纤维横截面积明显下降（P＜0.05），通气组与假训练组没有明显差异，而训练组膈肌纤维横截面积较通气组、假训练组有所增加（P＜0.05）。与对照组相比，通气组、假训练组、训练组膈肌中MDA含量、SBDP120水平、LC3II/I比值明显增多（P＜0.05），通气组、假训练组、训练组之间无差异。与对照组相比，通气组MAFbx表达明显增多（P＜0.05），通气组、假训练组、训练组之间无差异。与对照组和训练组相比，通气组、假训练组膈肌SBDP145水平明显升高（P＜0.05），通气组与假训练组膈肌SBDP145水平无差异；对照组与训练组膈肌SBDP145水平无差异。 结论：吸气肌训练能够改善VIDD膈肌形态和功能，其机制可能与钙蛋白酶的活性下降有关。

Abstract:

      Abstract Objective： To investigate the effect of inspiratory muscle training on diaphragm morphology and function in ventilator induced diaphragmatic dysfunction （VIDD） rats， and to explore the mechanism of it. Method： Twenty-four adult female SD rats were randomly divided into 4 groups：①Control group （n=6）；②Mechanical ventilation group （n=6）： mechanical ventilation for 24 hours； ③Sham training group （n=6）： spontaneous breathing for 1 hour after mechanical ventilation for 24 hours； ④Training group （n=6）： intermittent inspiratory muscle training for 1 hour after mechanical ventilation for 24 hours. Multi-channel physiology signal collection and processing system were used to detect the peak twitch tension and peak tetanic force of diaphragm， as well as the frequency-force effect curve. The cross-sectional area （CSA） of diaphragm was observed by hematoxylin and eosin staining method. Western-blot was used to detect the level of microtubule -associated protein 1 light chain 3 （LC3） and muscle atrophy F-box （MAFbx）. The levels of αII-spectrin breakdown products （SBDPs） SBDP145 and SBDP120 in the diaphragm were detected by ELISA. The level of malondialdehyde （MDA） in the diaphragm was detected by thiobarbituric acid （TBA） method. Result： Compared with control group and training group， the peak twitch tension， peak tetanic force and frequency-force effect curve of diaphragm in ventilation group and sham training group were decreased significantly （P<0.05）， but there was no difference between the ventilation group and the sham training group or between the control group and the training group. Compared with the control group， the diaphragm fiber cross-sectional area of ventilation group， sham training group or training group was significantly decreased （P<0.05），and there was no significant difference between the ventilation group and the sham training group. Compared with the ventilation group and the sham training group， the diaphragm fiber cross-sectional area of training group was increased （P<0.05）. Compared with the control group， the level of MDA， SBDP120 and LC3II/I ratio in the diaphragm of ventilation group， sham training group and training group were significantly increased （P<0.05）， and there was no difference between the ventilation group， the sham training group and the training group. Compared with the control group， the expression of MAFbx in ventilation group was significantly increased （P<0.05）， and there was no difference between the ventilation group， the sham training group and the training group. Compared with the control group and the training group， SBDP145 level in the diaphragm of ventilation group or sham training group was significantly increased （P<0.05）， but there was no difference between the ventilation group and the sham training group. There was no difference in SBDP145 level of diaphragm between the control group and the training group. Conclusion： Inspiratory muscle training can improve the morphology and function of VIDD diaphragm， and the mechanism may be related to the decrease of calpain activity.