电刺激膈神经逆转机械通气诱导膈肌功能不全影响的研究

Phrenic nerve stimulation protects against mechanical ventilation-induced diaphragmatic dysfunction through myogenic regulatory factors

目的探讨电刺激膈神经对机械通气过程中诱导的膈肌功能不全的保护作用。方法40只成年健康SD大鼠按照随机数字表法分为5组：空白对照组、自主呼吸组、电刺激组、机械通气组、电刺激协同机械通气组（协同组），每组8只。除空白对照组外，各组均给予气管插管18 h，自主呼吸组和电刺激组自主吸入空气，机械通气组给予潮气量1 ml/100 g机械通气，电刺激组和协同组经颈部电极外接导线进行电刺激。处死大鼠取膈肌组织，测量离体膈肌收缩力峰峰值与收缩最大速率，使用定量PCR法检测成肌分化抗原（MyoD）与肌细胞生成素的表达水平。结果协同组MyoD表达水平（吸光度值2^－ΔΔCt值）为（11.7±2.8），机械通气组表达水平为（40.9±24.7），差异有统计学意义（P﹤0.05）。肌细胞生成素在协同组（2.6±2.8）、机械通气组（1.6±0.7）与空白对照组间比较，差异有统计学意义（P〈0.05），但协同组与机械通气组比较差异无统计学意义（P〉0.05）。结论电刺激膈神经可能通过改变MyoD和肌细胞生成素的表达水平，部分抵消机械通气对膈肌功能的损伤，对膈肌有保护作用。

Objective To explore the protective effect of electrical stimulation of phrenic nerve on diaphragmatic function during mechanical ventilation. Methods Forty healthy adult SD rats were randomly divided into 5 groups ： blank control group （BC） , spontaneous breathing group （SB） , electrical stimulation group （ES）, mechanical ventilation group （MV）, and electrical stimulation and mechanical ventilation group （MS）. The rats in each group were treated for 18 h except for the BC group. After treatment, the diaphragm muscle tissue was obtained and the diaphragm contractility including peak-to-peak value （Vpp） and maximum rate of contraction （ ＋ dT/dt max ） were measured. Expression of MyoD and myogenin were detected. Results Except for the ES and the MS groups, there was a significant difference for peak-to-peak value （Vpp） between each 2 groups （ P 〈 0. 05 ）. Expression levels of MyoD in treatment groups were also significantly different （P 〈0. 05）. Expressions of MS（ Q-PCR 2^-ΔΔCt value-11.66 ±2. 80） and MV（ Q-PCR 2 -AaCt value ：40. 89 ± 24. 71 ） in the treatment group were significantly different （P 〈 0. 05 ）. The expression of myogenin in the MS and the MV groups were significantly different from those of the BC group （P 〈 0. 05）, however there was no significant difference between the MS（Q-PCR 2^-ΔΔCt value：2. 58±2. 75） and the MV group（ Q-PCR 2^-ΔΔCt value ： 1.63 ± 0. 71 ）. Conclusions Electrical stimulation of the phrenic nerve can change the expression level of MyoD and myogenin to offset mechanical ventilation induced diaphragmatic function damage, and therefore plays a protective effect on the diaphragm.