肺气肿兔膈肌力学模式对慢性超低频复合生理频率电刺激的适应性改变

目的研究不同频率慢性电刺激(CES)后肺气肿模型兔膈肌力学模式适应性变化,以了解慢性超低频电刺激对肺气肿兔膈肌力学特征的影响.方法采用木瓜蛋白酶雾化吸入法建立兔肺气肿模型;测定正常对照组、肺气肿组和肺气肿CES组膈肌颤搐收缩张力(Pt)、强直颤搐收缩张力(Po)、峰值张力时间(TPT)、1/2松弛时间(1/2Rt)、疲劳指数(FI)和疲劳恢复指数(FRI).结果①同正常对照组比较,肺气肿组Pt、Po降低(P＜0.01),TPT、1/2Rt延长(P＜0.01),FI、FRI增加(P＜0.01).②同肺气肿组比较,40 Hz和(2.5 40)Hz组Pt、Po明显增加(P＜0.01),TPT、1/2Rt明显缩短(P＜0.01),10 Hz组结果则相反(P＜0.05).40Hz、(2.5 40)Hz、10 Hz组FI、FRI明显下降(P＜0.01).③(2.5 40)Hz组与40 Hz组比较,Pt、Po、TPT、1/2Rt无显著统计学差异(P＞0.05),FI、FRI下降(P＜0.01).结论超低频复合生理频率慢性电刺激(2.5 40)Hz]可显著提高肺气肿兔的膈肌收缩力,较生理频率慢性电刺激(40 Hz)能使肺气肿兔膈肌抗疲劳能力得到更明显的提高.

Adaptation of emphysema rabbit diaphragm muscle mechanics to chronic ultra-low frequency electrical stimulation and chronic physiological frequency electrical stimulation

Objective To investigate the effect of chronic ultra-low frequency electrical stimulation on mechanical characteristic of diaphragmatic muscle of emphysema rabbit.Methods The rabbit model of emphysema was made by inhaling papain of ultrasonic atomization once a week for 3 weeks in 24 adult Japanese rabbits,6 receiving 10 Hz chronic ultra-low frequency electrical stimulation,6 receiving 40 Hz,6 receiving 2.5 Hz and 40 Hz.Another 6 rabbits served as control.The twitch tension (Pt),titanic tension(Po),time to peak tension(TPT),half-relaxation time(1/2RT),fatigue index(FI) and fatigue recovery index(FRI) were measured in control group,emphysema group,emphysema chronic ultra-low frequency electrical stimulation groups.Results As compared with the control rabbits, Pt and Po decreased,TPT and 1/2RT prolonged,FI and FRI increased in the only emphysema rabbits.Pt and Po were higher,TPR and 1/2Rt was shorter in the only emphysema rabbits than the rabbits in 40 Hz and(2.5 40) Hz groups(P<0.01),but completely opposite effect was observed in the rabbits in 10 Hz group(P<0.05).There was more significant decrease in FR and FRI in the rabbits in(2.5 40)Hz,40Hz and 10 Hz groups than that in only emphysema group(P<0.01).No significant difference in Pt,Po,TPT,1/2Rt(P>0.05),more increase in FR and FRI(P<0.01) in the rabbits in(2.5 40)Hz group than that in 40Hz group.Conclusion The resistance to diaphragm muscle fatigue was better improved in the combination of chronic ultra-low frequency electrical stimulation and chronic physiological frequency electrical stimulation(2.5 40)Hz than that of chronic physiological frequency electrical stimulation(2.5 Hz).