Role of miR-20a-5p in M1 microglia aggravating oxygen-glucose deprivation and restoration-induced injury to neurons: relationship with MFN2 / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of miR-20a-5p in M1 microglia aggravating oxygen-glucose deprivation and restoration (OGD/R)-induced injury to neurons and the relationship with mitofusin2 (MFN2).Methods:The well-growing BV2 microglia (M0 type) were polarized into M1 phenotype by lipopolysaccharide (100 ng/ml) and IFN-γ (20 ng/ml) and identified by quantitative real-time polymerase chain reaction and immunofluorescence.The well-growing N2a cells were divided into 6 groups ( n=6 each) by the random number table method: control group (group C), OGD/R group, M0 microglia co-culture group (group M0), M1 microglia co-culture group (group M1), miR-20a-5p inhibitor transfection group (group I) and negative control group (group NC). The cells were routinely cultured in group C, and the cells were subjected to OGD for 3 h followed by restoration of oxygen-glucose supply to develop the model of OGD/R injury in group OGD/R.The cells were subjected to OGD for 3 h and were co-cultured with M0 microglia for 24 h during restoration of oxygen-glucose supply in group M0.The cells were subjected to OGD for 3 h and were co-cultured with M1 microglia for 24 h during restoration of oxygen-glucose supply in group M1.In group I and group NC, cells were transfected with miR-20a-5p inhibitor and negative control miRNA into M1 microglia, respectively, and N2a cells were subjected to OGD for 3 h and co-cultured with M1 microglia for 24 h during restoration of oxygen-glucose supply.The cell viability was determined by cell counting kit-8 assay, amount of lactate dehydrogenase (LDH) released was determined, the expression of miR-20a-5p and MFN2 mRNA was detected by quantitative real-time polymerase chain reaction, and MFN2 expression was detected by Western blot. Results:Compared with group C, the cell viability was significantly decreased, the amount of LDH released was increased, and the expression of MFN2 protein and mRNA was down-regulated in the other five groups, miR-20a-5p expression was significantly up-regulated in OGD/R, M0 and M1 groups, and miR-20a-5p expression was significantly down-regulated in group I ( P<0.05). There were no significant differences in the cell viability, amount of LDH released, and expression of miR-20a-5p, MFN2 protein and mRNA between group OGD/R and group M0 ( P>0.05). Compared with group OGD/R and group M0, the cell viability was significantly decreased, the amount of LDH released was increased, and the expression of MFN2 protein and mRNA was down-regulated, and miR-20a-5p expression was up-regulated in group M1 ( P<0.05). Compared with group M1, the cell viability was significantly increased, the amount of LDH released was decreased, the expression of MFN2 protein and mRNA was up-regulated, and miR-20a-5p expression was down-regulated in group I ( P<0.05). Conclusions:The mechanism by which M1 microglia aggravates OGD/R-induced damage to N2a cells may be related to the up-regulation of miR-20a-5p expression in M1 microglia and the inhibition of MFN2 expression in N2a cells.