Role of miR-323b-5p in Inflammation, Oxidative Stress and Apoptosis During Cerebral Ischemia/Reperfusion Injury

Objective: The aims of this study is to investigate the potential effects of miR-323b-5p in an in vitro cerebral ischemia-reperfusion (I/R) model via targeting BCL2L11. Materials and methods: PC-12 cells exposed to oxygen-glucose deprivation/reperfusion condition (OGD/R) were classified into control, OGD/R model, miR-323b-5p inhibitor, inhibitor NC, sh-BCL2L11, shRNA NC, miR-323b5p inhibitor + shRNA NC, miR-323b-5p inhibitor + sh-BCL2L11, as well as the wild type cells. Cell apoptosis was observed by flow cytometry. The targeting relationship between miR-323b-5p and BCL2L11 was verified by luciferase assay. ELISA, qRT-PCR, and Western blot were performed to evaluate expressions of related molecules. Results: Compared with wild type, OGD/R significantly induced expression level of miR-323b-5p. In addition, downregulation of miR-323b-5p suppressed the OGD/R induced expression of pro-inflammation factors such as TNFα, IL-1β, IL-6 and monocyte chemotactic protein-1 (MCP-1), OGD/R induced reactive oxygen species (ROS) generation and lactate dehydrogenase (LDH) release. Increased ROS often leads to increased levels of malondialdehyde (MDA) and decreased anti-oxidants super oxide dismutase (SOD), and these OGD/R induced results were reversed by downregulation of miR-323b-5p. Decreased miR-323b-5p also inhibited the OGD/R induced apoptosis. Moreover, miR-323b-5p mediated apoptosis was mediated by directly targeting BCL2L11. Conclusions: miR-323b-5p may regulate cerebral I/R injury by targeting BCL2L11 and is a potential therapeutic and diagnostic biomarker for cerebral I/R injury.