title: Exercise in the Early Stage after Stroke Enhances Hippocampal Brain-Derived Neurotrophic Factor Expression and Memory Function Recovery.
abstract: BACKGROUND
  Exercise in the early stage after stroke onset has been shown to facilitate the recovery from physical dysfunction. However, the mechanism of recovery has not been clarified. In this study, the effect of exercise on spatial memory function recovery in the early stage was shown, and the mechanism of recovery was discussed using a rat model of brain embolism.
  
  
  METHODS
  Intra-arterial microsphere (MS) injection induced small emboli in the rat brain. Treadmill exercise was started at 24 hours (early group) or 8 days (late group) after MS injection. The non-exercise (NE) and sham-operated groups were included as controls. Memory function was evaluated by the Morris water maze test, and hippocampal levels of brain-derived neurotrophic factor (BDNF) were measured by enzyme-linked immunosorbent assays. To further investigate the effect of BDNF on memory function, BDNF was continuously infused into the hippocampus via implantable osmotic pumps in the early or late stage after stroke.
  
  
  RESULTS
  Memory function significantly improved only in the early group compared with the late and the NE groups, although hippocampal BDNF concentrations were temporarily elevated after exercise in both the early and the late groups. Rats infused with BDNF in the early stage exhibited significant memory function recovery; however, rats that received BDNF infusion in the late stage showed no improvement.
  
  
  CONCLUSIONS
  Exercise elevates hippocampal BDNF levels in the early stage after cerebral embolism, and this event facilitates memory function recovery.
authors.affiliation: Second Department of Physiology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Himi
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Takahashi
authors.affiliation: Second Department of Physiology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
authors.forename: Naohiko
authors.initials: N
authors.lastname: Okabe
authors.affiliation: Second Department of Physiology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
authors.forename: Emi
authors.initials: E
authors.lastname: Nakamura
authors.affiliation: Department of Stroke, Kawasaki Medical School, Kurashiki, Okayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiromoto
authors.affiliation: Second Department of Physiology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Narita
authors.affiliation: Department of Rehabilitation, Kawasaki University of Medical Welfare, Kurashiki, Okayama, Japan.
authors.forename: Tomoshige
authors.initials: T
authors.lastname: Koga
authors.affiliation: Second Department of Physiology, Kawasaki Medical School, Kurashiki, Okayama, Japan. Electronic address: mosamu@med.kawasaki-m.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Miyamoto
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects; D019208:Brain-Derived Neurotrophic Factor / Q000008:administration & dosage / Q000378:metabolism*; D053148:Caspase 3 / Q000378:metabolism; D004195:Disease Models, Animal; D005081:Exercise Therapy; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D007263:Infusions, Parenteral; D020766:Intracranial Embolism / Q000378:metabolism / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D008297:Male; D018782:Maze Learning; D008568:Memory / Q000187:drug effects; D008569:Memory Disorders / Q000378:metabolism / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D017207:Rats, Sprague-Dawley; D020521:Stroke / Q000378:metabolism / Q000503:physiopathology / Q000523:psychology / Q000628:therapy*; D013997:Time Factors; D015854:Up-Regulation
chemical_list: D019208:Brain-Derived Neurotrophic Factor; C579455:BDNF protein, human; C505410:Casp3 protein, rat; D053148:Caspase 3
keywords: BDNF; Rat; embolism; exercise; memory function recovery