MicroRNA-489-3p aggravates neuronal apoptosis and oxidative stress after cerebral ischemia-reperfusion injury

Cerebral ischemia-reperfusion injury (CIRI) mostly occurs in the treatment stage of ischemic diseases and aggravate brain tissue damage. Although studies have demonstrated that miR-489-3p is closely related to CIRI, the effects of miR-489-3p on neural function in CIRI have not been directly studied. The transient middle cerebral artery occlusion (tMCAO) model was established by suture method, and the corresponding plasmids that interfered with the expression of miR-489-3p or Sirtuin1 (SIRT1) were injected into the model mice, and the behavioral changes of the mice were observed. Then the concentration of serum neuronal injury markers and oxidative stress indices were examined. Next, the pathological conditions, neuronal loss and apoptosis of brain tissue were observed by hematoxylin-eosin staining, Nissl staining, and Transferase-mediated deoxyuridine triphosphate-biotin nick end labeling staining. Finally, the hemoglobin content and cerebral edema in the mouse brain were determined. In addition, the expression levels of miR-489-3p and SIRT1 were detected by reverse transcription quantitative polymerase chain reaction or Western blot, and the targeting relationship between miR-489-3p and SIRT1 was verified by bioinformatics analysis and luciferase reporter assay. The experimental results found that in tMCAO mice, miR-489-3p in brain tissue was up-regulated and SIRT1 was down-regulated. Down-regulating miR-489-3p or up-regulating SIRT1 ameliorated behavioral dysfunction, neuronal damage and apoptosis, oxidative stress and brain histopathology. miR-489-3p targeted the regulation of SIRT1 expression, and down-regulating SIRT1 can reverse the protective effect of silenced miR-489-3p on brain injury. Taken together, by targeting SIRT1, elevated miR-489-3p aggravates CIRI-induced neuronal apoptosis and oxidative stress.