title: Fluoxetine prevents oligodendrocyte cell death by inhibiting microglia activation after spinal cord injury.
abstract: Oligodendrocyte cell death and axon demyelination after spinal cord injury (SCI) are known to be important secondary injuries contributing to permanent neurological disability. Thus, blocking oligodendrocyte cell death should be considered for therapeutic intervention after SCI. Here, we demonstrated that fluoxetine, an antidepressant drug, alleviates oligodendrocyte cell death by inhibiting microglia activation after SCI. After injury at the T9 level with a Precision Systems and Instrumentation (Lexington, KY) device, fluoxetine (10 mg/kg, intraperitoneal) was administered once a day for the indicated time points. Immunostaining with CD11b (OX-42) antibody and quantification analysis showed that microglia activation was significantly inhibited by fluoxetine at 5 days after injury. Fluoxetine also significantly inhibited activation of p38 mitogen-activated protein kinase (p38-MAPK) and expression of pro-nerve growth factor (pro-NGF), which is known to mediate oligodendrocyte cell death through the p75 neurotrophin receptor after SCI. In addition, fluoxetine attenuated activation of Ras homolog gene family member A and decreased the level of phosphorylated c-Jun and, ultimately, alleviated caspase-3 activation and significantly reduced cell death of oligodendrocytes at 5 days after SCI. Further, the decrease of myelin basic protein, myelin loss, and axon loss in white matter was also significantly blocked by fluoxetine, as compared to vehicle control. These results suggest that fluoxetine inhibits oligodendrocyte cell death by inhibiting microglia activation and p38-MAPK activation, followed by pro-NGF production after SCI, and provide a potential usage of fluoxetine for a therapeutic agent after acute SCI in humans.
authors.affiliation: 1 Age-Related and Brain Diseases Research Center, Kyung Hee University , Seoul, Korea.
authors.forename: Jee Y
authors.initials: JY
authors.lastname: Lee
authors.forename: So R
authors.initials: SR
authors.lastname: Kang
authors.forename: Tae Y
authors.initials: TY
authors.lastname: Yune
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D004195:Disease Models, Animal; D004334:Drug Administration Schedule; D005473:Fluoxetine / Q000627:therapeutic use*; D007274:Injections, Intraperitoneal; D008262:Macrophage Activation / Q000187:drug effects; D008297:Male; D008810:Mice, Inbred C57BL; D017628:Microglia / Q000187:drug effects*; D020932:Nerve Growth Factor / Q000378:metabolism; D009836:Oligodendroglia / Q000187:drug effects*; D017367:Selective Serotonin Reuptake Inhibitors / Q000627:therapeutic use*; D013119:Spinal Cord Injuries / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D005473:Fluoxetine; D020932:Nerve Growth Factor; D017367:Selective Serotonin Reuptake Inhibitors; D048051:p38 Mitogen-Activated Protein Kinases
keywords: fluoxetine; inflammation; microglia; oligodendrocyte; p38-MAPK