Study on the mechanism of resolvin D1 in alleviating brain injury after cardiopulmonary resuscitation through the inhibition of autophagy in pigs / 中华急诊医学杂志

ABSTRACT

Objective:To investigate the mechanism of resolvin D1 (RvD1) in alleviating brain injury after cardiopulmonary resuscitation (CPR) through regulating autophagy pathway in pigs.Methods:Nineteen male domestic pigs, weighing 30-41 kg, were divided into 3 groups using a random number table method: sham group (S group, n=5), CPR group ( n=7), and RvD1 group ( n=7). In the S group, the animals only experienced general preparation. In the CPR and RvD1 groups, the pig CPR model was established by 8 min of cardiac arrest caused by electrically induced ventricular fibrillation, and followed by 5 min of CPR. At 5 min after resuscitation, a dose of 0.6 μg/kg of resolvin D1 was injected via femoral vein in the RvD1 group, and the same amount of vehicle was similarly administered in the other two groups. At 1, 3, 6, and 24 h after resuscitation, blood samples were collected from the femoral vein to measure serum concentrations of neuron specific enolase (NSE) and S100β protein by ELISA. At 24 h after resuscitation, neurological function was evaluated by neurological deficit score (NDS), and then the animals were euthanized to obtain cerebral cortex for measuring the expressions of phosphorylated AMP-activated protein kinase (p-AMPK), phosphorylated mammalian target of rapamycin (p-mTOR), microtubule-associated protein light chain 3 (LC3 II) and p62 by Western blot. The variables were compared with One-way analysis of variance and then the Bonferroni test among the three groups. Results:During 24 h after resuscitation, the NDS was significantly increased accompanied with significantly greater concentrations of NSE and S100β in serum in the CPR and RvD1 groups compared to the S group (all P<0.05). However, the NDS was significantly decreased at 24 h after resuscitation [(182±34) vs.(124±18), P<0.05], and serum NSE and S100β were significantly reduced starting 3 h after resuscitation in the RvD1 group compared to the CPR group [NSE (ng/mL) (23.1±3.8) vs. (18.0±2.2) at 3 h, (27.3±2.9) vs. (19.8±1.4) at 6 h, and (28.1±1.3) vs. (15.1±2.1) at 24 h; S100B (pg/mL) (1 611±208) vs. (1 322±100) at 3 h, (1 825±197) vs. (1 410±102) at 6 h, and (1 613±138) vs. (1 183±139) at 24 h, all P<0.05]. The expression levels of p-AMPK and LC3 II were significantly increased while the expression levels of p-mTOR and p62 were significantly decreased at 24 h after resuscitation in the CPR and RvD1 groups compared to the S group (all P<0.05). However, the expression levels of p-AMPK and LC3 II were significantly lower and the expression levels of p-mTOR and p62 were significantly higher at 24 h after resuscitation in the RvD1 group compared to the CPR group [p-AMPK (0.28±0.08) vs. (0.17±0.03); LC3 II (0.33±0.09) vs. (0.21±0.04); p-mTOR (0.13±0.02) vs. (0.16±0.02); p62 (0.16±0.05) vs. (0.22±0.02), all P<0.05]. Conclusions:The protective mechanism by which RvD1 alleviates brain injury after CPR in pigs might be related to the inhibition of neuronal autophagy mediated by AMPK/mTOR pathway.