Silencing of long noncoding RNA MEG3 enhances cerebral protection of dexmedetomidine against hypoxic-ischemic brain damage in neonatal mice by binding to miR-129-5p

Hypoxic-ischemic brain damage (HIBD) is a leading cause of neonatal acute mortality and chronic nervous system injury. Recently, it has been found that long noncoding RNAs (lncRNAs) play a significant role in the neurodevelopment and etiopathogenesis of HIBD. Here, the researchers aimed to determine the role of lncRNA maternally expressed gene (MEG3) in the therapeutic effect of dexmedetomidine (DEX) in neonatal mice with HIBD through the regulation of microRNA-129-5p (miR-129-5p). HIBD models were established in C57/BL6 neonatal mice. Subsequently, the target relationship between MEG3 and miR-129-5p was predicted and verified. The neonatal mice were injected with DEX, ad-shMEG3, and mimics and inhibitors of miR-129-5p to identify roles of MEG3 and miR-129-5p in therapeutic effects of DEX on neuronal apoptosis and injury, cerebral atrophy, and learning and memory ability of neonatal mice with HIBD. MEG3 directly targeted and inhibited the expression of miR-129-5p. Silencing of MEG3 or upregulation of miR-129-5p effectively promoted the therapeutic effect of DEX on neonatal mice with HIBD. Silencing of MEG3 or upregulation of miR-129-5p reduced the neuronal apoptosis rate and degree of cerebral atrophy, and also enhanced the learning and memory ability of HIBD neonatal mice. Collectively, the key findings obtained from the present study support the notion that MEG3 silencing enhances the therapeutic effect of DEX on neonatal mice with HIBD by binding to miR-129-5p.