The effect of vagus nerve stimulation on the prognosis of rats after cardiopulmonary resuscitation under different treatment timings / 中华急诊医学杂志

ABSTRACT

Objective:To explore the protective effect of vagus nerve stimulation (VNS) on the prognosis of rats suffering from cardiac arrest/cardiopulmonary resuscitation (CA/CPR) under different treatment timings.Methods:The method of percutaneous epicardial electrical stimulation was used to establish CA model of rat. Fifty-three male SD rats were randomly (random number) divided into the sham group ( n=5), CPR group ( n=12), PRE group ( n=12), POST5 group ( n=12) and POST30 group ( n=12). The sham group did not experience CA/CPR. VNS treatment was started at 30 min before CA (PRE group, n=12), 5 min after recovery of spontaneous circulation (ROSC) (POST5 group, n=12), and 30 min after ROSC (POST30 group, n=12) in different VNS-treated group, respectively. The electrical stimulation was applied to the vagus nerve for 30 min with a unified parameter. The neurological deficit scores at 24, 48, and 72 h after ROSC were recorded, and the survival rate in each group was observed. TUNEL staining was used to detect the apoptosis of cortical area and the expression of α7 nicotinic acetylcholine receptor (α7nAChR) in brain tissue was measured by immunofluorescence at 72 h after ROSC. Variables were compared with one-way analysis of variance, and survival for Kaplan-Meier curves were tested with the log-rank test. A P value less than 0.05 was considered statistically significant. Results:Compared with the CPR group (survival rate 33.33%), both pre-treatment (survival rate 75%) and post-treatment of VNS (POST5 group survival rate 75% and POST30 group survival rate 83.33%) significantly improved the 72 h survival rate after CPR ( P<0.05), mitigated neurological deficits after ROSC, reduced the positive rate of apoptosis neurons, and up-regulated the expression of α7nAChR in cerebral cortex. There was no significant difference among the VNS-treated groups (all P>0.05). Conclusions:Both pre-treatment and post-treatment of VNS can play a protective role in rats after CA/CPR, which may be related to the activation of α7nAChR-mediated anti-inflammatory and anti-apoptosis effects.