Role of miR-124-3p in reduction of oxygen-glucose deprivation and restoration injury by electrostimulation preconditioning in microglia: relationship with microglia polarization / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of miR-124-3p in reduction of oxygen-glucose deprivation and restoration (OGD/R) injury by electrostimulation preconditioning in microglia and its relationship with microglial polarization.Methods:The well-growing BV2 cells were divided into 4 groups ( n=30 each) by the random number table method: control group (group C), OGD/R group, electrostimulation preconditioning group (group E) and miR-124-3p inhibitor group (group I). Group C was cultured under normal conditions, and group OGD/R was deprived of oxygen and glucose for 2 h followed by restoration of oxygen and glucose supply for 24 h to develop the OGD/R injury model. In group E, cells were stimulated with 100 mV/mm direct current for 4 h before oxygen-glucose deprivation, and the other treatments were similar to those previously described in group OGD/R. Group I was transfected with micrOFF? mmu-miR-124-3p inhibitor at 48 h before oxygen-glucose deprivation, and the other treatments were similar to those previously described in group E. The cell survival rate was determined by CCK-8 assay, the concentrations of tumor necrosis factor-α (TNF-α), interleukin 1β (IL-1β) and IL-10 in the cell supernatant were measured by enzyme-linked immunosorbent assay. The expression of a surface marker of M1 microglia inducible nitric oxide synthase (iNOS) and a surface marker of M2 microglia arginase 1 (Arg-1) was detected by immunofluorescence and Western blot, respectively. The expression of iNOS and Arg-1 mRNA and miR-124-3p was detected by quantitative polymerase chain reaction. Results:Compared with group C, the cell survival rate was significantly decreased, the concentrations of TNF-α, IL-1β and IL-10 in the supernatant were increased, and the expression of iNOS and Arg-1 protein and mRNA and miR-124-3p was up-regulated in the remaining three groups ( P<0.05). Compared with group OGD/R, the cell survival rate was significantly increased, the concentrations of TNF-α and IL-1β in the supernatant were decreased, the IL-10 concentration was increased, the expression of iNOS protein and mRNA was down-regulated, and the expression of Arg-1 protein and mRNA and miR-124-3p was up-regulated in E and I groups ( P<0.05). Compared with group E, the cell survival rate was significantly decreased, the concentrations of TNF-α and IL-1β in the supernatant were increased, the IL-10 concentration was decreased, the expression of iNOS protein and mRNA was up-regulated, and the expression of Arg-1 protein and mRNA and miR-124-3p was down-regulated in group I ( P<0.05). Conclusions:The mechanism by which electrostimulation preconditioning reduces OGD/R injury in microglia is related to up-regulation of the expression of miR-124-3p, promotion of M2 microglia polarization, inhibition of M1 microglia polarization, and thus inhibiting the inflammatory responses.