title: Ischemic preconditioning attenuates of ischemia-induced degradation of spectrin and tau: implications for ischemic tolerance.
abstract: Global ischemia selectively induces CA1 neuronal death in the hippocampus. Pretreatment with non-lethal ischemia (i.e. ischemic preconditioning) prevents CA1 neuronal death induced by lethal ischemia. While ischemic tolerance is a well-known phenomenon, the underlying molecular mechanisms are not fully understood. Cytoskeletal proteins including α-spectrin, tau, and microtubule-associated protein 2 (MAP-2) are indispensable for the maintenance of neuronal homeostasis. Here, we report the effects of ischemic preconditioning on the ischemia-induced degradation of cytoskeletal proteins α-spectrin, tau, and MAP-2 in the rat CA1 region. We found that most neurons of the CA1 region had died after 5 min of ischemia. However, exposing the brain to 3 min of ischemic preconditioning 3 days earlier significantly reduced the number of neuronal death. A significant degradation of α-spectrin and tau, but not of MAP-2, was found in the CA1 region after 5 min of ischemia. Ischemic preconditioning attenuated the ischemia-induced massive degradation of α-spectrin and tau. Our results suggest that the attenuation of ischemia-induced degradation of α-spectrin and tau by ischemic preconditioning may be associated with the neuroprotective mechanism of the ischemic tolerance.
authors.affiliation: Department of Veterinary Anatomy, Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 1-58 Rinku-Ohraikita, Izumisano, Osaka, 598-8531, Japan. t-nakaji@vet.osakafu-u.ac.jp
authors.forename: Takayuki
authors.initials: T
authors.lastname: Nakajima
authors.forename: Syoichi
authors.initials: S
authors.lastname: Ochi
authors.forename: Chika
authors.initials: C
authors.lastname: Oda
authors.forename: Maki
authors.initials: M
authors.lastname: Ishii
authors.forename: Kazushige
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D000818:Animals; D015153:Blotting, Western; D002545:Brain Ischemia / Q000378:metabolism* / Q000473:pathology; D006624:Hippocampus / Q000378:metabolism* / Q000473:pathology; D007150:Immunohistochemistry; D019194:Ischemic Preconditioning; D008297:Male; D008869:Microtubule-Associated Proteins / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013049:Spectrin / Q000378:metabolism*; D016875:tau Proteins / Q000378:metabolism*
chemical_list: D008869:Microtubule-Associated Proteins; D016875:tau Proteins; D013049:Spectrin