Significant Role of microRNA-182-5p in Neonatal Hypoxic-Ischemic Injury and Related Mechanism

Abstract

The purpose of current study was to explore the role and mechanism of microRNA-182-5p (miR182-5p) in neonatal hypoxic ischemic brain damage (HIBD). First, we established a hypoxic-ischemic (HI) rat model and assessed the neurological function of the rats using the Zea Longa score. Then, the level of miR-182-5p in brain tissue of neonatal rats was determined by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Findings revealed that miR-182-5p was significantly down-regulated in the brain tissue of HI rat model. Next, we studied the target gene of miR-182-5p by using TargetScan and dual luciferase reporter assay. Results showed that CASP2 was a direct target gene of miR-182-5p, and the level of CASP2 was significantly up-regulated in the brain tissue of HI rat model. Immediately thereafter, we established an oxygen and glucose deprivation (OGD) cell model of primary cortical neurons, and demonstrated the changes of miR182-5p in cells treated with OGD by qRT-PCR. Finally, to determine the function of miR-182-5p in OGD subjected neuronal cells, 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and flow cytometry (FCM) assays were used to study cell viability and apoptosis. The study found that compared with the OGD group, miR-182-5p mimic significantly increased nerve cell viability, reduced cell apoptosis and decreased cleaved-Caspase3/7/8 protein expression, however, all these changes were significantly reversed by overexpression of the CASP2 gene. Taken together, miR-182-5p might protect the nerve cells from ischemia and hypoxia by targeting CASP2, thereby playing a protective role in hypoxic ischemic encephalopathy, which might be a new effective target for neonatal hypoxic ischemic brain damage treatment.