Effect of edaravone on ERK-CREB signaling pathway in hippocampus of aged rats with postoperative cognitive dysfunction / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the effect of edaravone on the extracellular signal-regulated kinase (ERK)-cAMP responsive element binding protein (CREB) signaling pathway in the hippocampus of aged rats with postoperative cognitive dysfunction (POCD).Methods:Sixty SPF healthy male Sprague-Dawley rats, aged 20 months, weighing 650-700 g, were divided into 4 groups ( n=15 each) using a random number table method: control group (group C), POCD group (group P), edaravone group (group E) and ERK inhibitor group (group I). The rats received laparotomy under 3% sevoflurane anesthesia to prepare POCD model in P, E and I groups. Edaravone 3 mg/kg was intraperitoneally injected at 30 min before operation in E and I groups, ERK inhibitor PD98059 0.3 mg/kg was injected via the tail vein in group I. The open field test was performed at 3 days after operation to evaluate the spontaneous activity of rats, then Morris water maze test was performed to evaluate the cognitive function of rats on 3-7 days after operation. The rats were sacrificed after the end of Morris water maze test, and hippocampal tissues were obtained for determination of the expression of phosphorylated ERK (p-ERK), phosphorylated CREB (p-CREB), synaptophysin and postsynaptic density protein 95 (PSD-95) (by Western blot) and dendrite length and density of dendrites in hippocampal CA1 area (using Golgi staining). Results:Compared with group C, the escape latency was significantly prolonged after operation, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was down-regulated, and the dendritic length and density of hippocampal neurons were reduced in group P ( P<0.05). Compared with group P, the escape latency was significantly shortened, the number of crossing the original platform was increased, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was up-regulated, and the dendritic length and density of hippocampal neurons were increased in group E ( P<0.05). Compared with group E, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the expression of p-ERK, p-CREB, synaptophysin and PSD-95 was down-regulated, the dendritic length of hippocampal neurons was shortened, and the density of hippocampal neurons was decreased in group I( P<0.05). Conclusions:The mechanism by which edaravone improves POCD may be related to activating ERK/CREB signaling pathway and changing synaptic plasticity in hippocampal CA1 region in aged rats.