RESUMO
Objective:To evaluate the relationship between hippocampal miR-3065-5p and insulin-like growth factor-1/phosphatidylinositol 3-kinase/protein kinase B(IGF-1/PI3K/Akt)signaling pathway in a mouse model of perioperative neurocognitive disorder (PND).Methods:Eighty clean-grade healthy male C75BL/6 mice, aged 12-14 weeks, weighing 20-30 g, were divided them into 4 groups ( n=20 each) using the random number table method: control group (C group), PND group, miR-3065-5p agonist group (Ag group) and miR-3065-5p agonist negative control group (Ag-NC group). PND model was prepared by internal fixation of tibial fracture under anesthesia with 1.5% isoflurane. Two days before developing the model, miR-3065-5p agomir 2 μl was injected into the lateral ventricle in Ag group, miR-3065-5p agomir negative control 2 μl was injected into the lateral ventricle in Ag-NC group. Morris water maze test and open field test were performed at 7 days after surgery. The mice were sacrificed after the end of test, and hippocampal tissues were obtained for determination of the expression of miR-3065-5p, IGF-1 mRNA and Bcl-2 mRNA (by quantitative real-time polymerase chain reaction) and expression of IGF-1, phosphorylated Akt (p-Akt), phosphorylated glycogen synthase kinase-3β (p-GSK3β) and Bcl-2 (by Western blot). Results:There was no significant difference in each parameter in the open field test among the four groups ( P>0.05). Compared with group C, the postoperative escape latency was significantly prolonged, the percentage of time of stay at the target quadrant was decreased, the number of crossing the original platform was reduced, the expression of miR-3065-5p was up-regulated, and the expression of IGF-1 mRNA, Bcl-2 mRNA, IGF-1, p-Akt, p-GSK3β and Bcl-2 was down-regulated in the other three groups ( P<0.05). Compared with PND group and Ag-NC group, the postoperative escape latency was significantly prolonged, the percentage of time of stay at the target quadrant was decreased, the number of crossing the original platform was reduced, the expression of miR-3065-5p was up-regulated, and the expression of IGF-1 mRNA, Bcl-2 mRNA, IGF-1, p-Akt, p-GSK3β and Bcl-2 was down-regulated in Ag group ( P<0.05). Conclusions:Up-regulation of miR-3065-5p can inhibit the activation of IGF-1/PI3K/Akt signaling pathway, which might be one of the mechanisms of PND developed in mice.
