Inhibition of miR-200b-3p alleviates hypoxia-ischemic brain damage via targeting Slit2 in neonatal rats

Abstract Background Brain damage in premature infants often occurs in very low birth weight infants (VLBW) as a result of hypoxia-ischemia and can lead to cognitive impairment and movement disorders. Many miRNAs have been demonstrated to participate in hypoxia-ischemic brain damage (HIBD). This study was designed to investigate the roles of miR-200b-3p in brain damage of neonatal rats induced by hypoxia-ischemia. Methods and results Three-day-old SD rats were used to establish the model of hypoxia-ischemic brain injury mimicking premature infants. RT-qPCR showed that miR-200b-3p was up-regulated in rat brains at the early stage following hypoxia-ischemic treatment. Bioinformatics analysis identified that Slit2 is a target gene of miR-200b-3p and luciferase reporter gene assay confirmed that miR-200b-3p can interact with and target Slit2 mRNA. Inhibition of miR-200b-3p by antagomir increased Slit2 expression at both the mRNA and protein levels in rat brains. TUNEL assay and transmission electron microscopy (TEM) analysis showed decreased numbers of apoptotic neurons in the hypoxia-ischemia-treated animals as a result of administration of miR-200b-3p antagomir. Administration of miR-200b-3p antagomir attenuated spatial and learning memory loss in the animals induced by hypoxia-ischemia as compared to controls. Conclusion Our study has demonstrated that Slit2 is a target gene of miR-200b-3p and that the hypoxia-ischemic brain damage in neonatal rats was alleviated by inhibiting miR-200b-3p via Slit2. miR-200b-3p may be a potential therapeutic target of HIBD for further investigation.