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

To explore the protective effect of electrical stimulation of phrenic nerve on diaphragmatic function during mechanical ventilation. 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. Except for the ES and the MS groups, there was a significant difference for peak-to-peak value (Vpp) between each 2 groups (<0.05). Expression levels of MyoD in treatment groups were also significantly different (<0.05). Expressions of MS(Q-PCR 2(-ΔΔCt) value: 11.66±2.80) and MV(Q-PCR 2(-ΔΔCt) value: 40.89±24.71) in the treatment group were significantly different (<0.05). The expression of myogenin in the MS and the MV groups were significantly different from those of the BC group(<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). 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.