Mechanism Study and Analysis of Correlation between miR-409-3p and Post-Stroke Cognitive Impairment.

Post-stroke cognitive impairment (PSCI) is a common sequela that occurs after ischaemic stroke (IS). This study aimed to investigate whether miR-409-3p is related to PSCI. Patients with IS were divided into two subgroups: PSCI and post-stroke cognitive normality (PSCN). The plasma level of miR-409-3p was determined by RT-qPCR. The association between PSCI and miR-409-3p was evaluated through binary logistic regression and by analysing the correlation between miR-409-3p and the MoCA score. In mice with middle cerebral artery occlusion (MCAO), the effects of miR-409-3p on cognitive function were explored through mNSS score and Morris water maze. In OGD/R-induced SH-SY5Y cells, the effects of miR-409-3p on cell viability, apoptosis and neuronal inflammation were evaluated using CCK-8, flow cytometry and ELISA. The content of miR-409-3p in patients with IS and those with PSCI was both increased, and its content showed a significant negative correlation with the MoCA score. The binary logistic regression analysis showed that a high risk of PSCI was associated with miR-409-3p. In MCAO mice, inhibition of miR-409-3p can significantly reduce the mNSS score and shorten the escape latency in the Morris water maze. Further-more, in neurons induced by OGD/R, down-regulation of miR-409-3p can exert a significant protective effect on neurons, manifested by enhanced cell viability, reduced apoptosis rate and inhibition of the synthesis of inflammatory factors. We conclude that miR-409-3p is a risk factor associated with PSCI. In MCAO mice and neurons induced by OGD/R, inhibition of miR-409-3p significantly alleviated neurological deficits and suppres-sed neuronal apoptosis and neuronal inflammation.