title: Effects of edaravone on a rat model of punch-drunk syndrome.
abstract: Punch-drunk syndrome (PDS) refers to a pathological condition in which higher brain dysfunction occurs in a delayed fashion in boxers who have suffered repeated blows to the head. However, the underlying mechanisms remain unknown. This study attempted to elucidate the mechanism of higher brain dysfunction observed following skull vibration in two experiments involving a rat model of PDS. Experiment 1 evaluated the effects of edaravone on histological changes in the rat brain tissue after skull vibration (frequency 20 Hz, amplitude 4 mm, duration 60 minutes). The amount of free radicals formed in response to skull vibration was very small, and edaravone administration reduced the number of glial fibrillary acidic protein and advanced glycation end product-positive cells. Experiment 2 examined the time course of change in learning ability following skull vibration in Tokai High Avoider rats. The learning ability of individual rats was evaluated by the Sidman-type electric shock avoidance test 5 days after the last session of skull vibration or final anesthesia and once a month for 9 consecutive months. Delayed learning disability was not observed in rats administered edaravone immediately after skull vibration. These results suggest that free radical-induced astrocyte activation and subsequent glial scar formation contribute to the occurrence of delayed learning disabilities. Edaravone administration after skull vibration suppressed glial scar formation, thereby inhibiting the occurrence of delayed learning disabilities.
authors.affiliation: First Department of Neurosurgery, School of Medicine, Faculty of Medicine, Toho University Omori Medical Center, Tokyo, Japan. jn_nomoto@infoseek.jp
authors.forename: Jun
authors.initials: J
authors.lastname: Nomoto
authors.forename: Takao
authors.initials: T
authors.lastname: Kuroki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nemoto
authors.forename: Kosuke
authors.initials: K
authors.lastname: Kondo
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Harada
authors.forename: Takeki
authors.initials: T
authors.lastname: Nagao
mesh_terms: D000818:Animals; D000983:Antipyrine / Q000031:analogs & derivatives* / Q000494:pharmacology; D001265:Athletic Injuries / Q000473:pathology / Q000503:physiopathology*; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D001914:Boxing / Q000293:injuries*; D001924:Brain Concussion / Q000473:pathology / Q000503:physiopathology*; D020208:Brain Injury, Chronic / Q000473:pathology / Q000503:physiopathology*; D002531:Cerebellum / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D002540:Cerebral Cortex / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D003337:Corpus Callosum / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D004195:Disease Models, Animal; D000077553:Edaravone; D005239:Fear / Q000187:drug effects* / Q000502:physiology; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006624:Hippocampus / Q000187:drug effects / Q000473:pathology / Q000503:physiopathology; D008570:Memory, Short-Term / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D013577:Syndrome; D014732:Vibration / Q000009:adverse effects
chemical_list: D016166:Free Radical Scavengers; D000077553:Edaravone; D000983:Antipyrine