Remote ischemic perconditioning (RIPerC) could improve neuronal damage and inhibit inflammation and apoptosis. We conducted an in-depth exploration of the protective mechanism of RIPerC in cerebral ischaemia injury. In this study, a middle cerebral artery occlusion (MCAO) mouse model was built. According to whether to undergo RIPerC treatment and the duration of cerebral infarction, mice were divided into 5 groups: Sham group, MCAO 3.0 h group, MCAO 4.5 h group, MCAO 3.0 h + RIPerC group, and MCAO 4.5 h + RIPerC group. Overexpressed or silenced miR-153-5p was transfected into the cells to analyse the effects of oxygen-glucose deprivation (OGD) treatment on Neuro-2a cell viability, apoptosis, and related gene expressions by performing quantitative real-time polymerase chain reaction (qRT-PCR), MTT assay, flow cytometry, and Western blot. Bioinformatics analysis, qRT-PCR, dual-luciferase experiment, and RNA immunoprecipitation (RIP) were used to screen and verify the miRNA and downstream mRNA-targeted Toll-like receptor 4 (TLR4). The rescue test further verified the effects of the above target genes and miR-153-5p on the apoptosis of OGD-injured cells, apoptosis-related proteins, and the p65/IkBa pathway. The plasma levels of miR-153-5p in 68 patients with ischaemic stroke were detected within 6 hours of onset, and the patients were followed up for 3 months. We found that, in in vivo studies, RIPerC treatment inhibits cerebral infarction volume and neurological damage, and promotes the expression of miR-153-5p in the MCAO animal model. The expression of miR-153-5p in OGD cells was inhibited, and its upregulation protected Neuro-2a cells. TLR4 was predicted to be the target gene of miR-153-5p and could offset the effect of miR-153-5p mimic on OGD cell protection after up-regulating TLR4. TLR4 overexpression promoted the activation of OGD on the p65/IkBa pathway. Compared with the high plasma miR-153-5p group, the 3-month overall survival rate of patients with ischaemic stroke in the low plasma miR-153-5p group was significantly lower (c2 = 5.095, p = 0.024). In conclusion, RIPerC intervention inhibits the damage caused by cerebral ischaemia partially through the miR-153-5p/TLR4/p65/IkBa signalling pathway.
Keywords: TLR4; middle cerebral artery occlusion; stroke; remote ischaemic perconditioning.