title: Changes in expression of aquaporin-4 and aquaporin-9 in optic nerve after crushing in rats.
abstract: The purpose of this study was to determine the temporal and spatial changes in the expression of AQP4 and AQP9 in the optic nerve after it is crushed. The left optic nerves of rats were either crushed (crushed group) or sham operated (sham group), and they were excised before, and at 1, 2, 4, 7, and 14 days later. Four optic nerves were pooled for each time point in both groups. The expression of AQP4 and AQP9 was determined by western blot analyses. Immunohistochemistry was used to determine the spatial expression of AQP4, AQP9, and GFAP in the optic nerve. Optic nerve edema was determined by measuring the water content in the optic nerve. The barrier function of the optic nerve vessels was determined by the extravasated Evans blue dye on days 7 and 14. The results showed that the expression of AQP4 was increased on day 1 but the level was significantly lower than that in the sham group on days 4 and 7 (P<0.05). In contrast, the expression of AQP9 gradually increased, and the level was significantly higher than that in the sham group on days 7 and 14 (P<0.05, Tukey-Kramer). The down-regulation of AQP4 was associated with crush-induced optic nerve edema, and the water content of the nerve was significantly increased by 4.3% in the crushed optic nerve from that of the untouched fellow nerve on day 7. The expression of AQP4 and GFAP was reduced at the crushed site where AQP4-negative and AQP9-positive astrocytes were present. The barrier function was impaired at the crushed site on days 7 and 14, restrictedly where AQP4-negative and AQP9-positive astrocytes were present. The presence of AQP9-positive astrocytes at the crushed site may counteract the metabolic damage but this change did not fully compensate for the barrier function defect.
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Hidehiro
authors.initials: H
authors.lastname: Oku
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Horie
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Seita
authors.initials: S
authors.lastname: Morishita
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tonari
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Oku
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Okubo
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Teruyo
authors.initials: T
authors.lastname: Kida
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Mimura
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Masanori
authors.initials: M
authors.lastname: Fukumoto
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Shota
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Takai
authors.affiliation: Department of Ophthalmology, Osaka Medical College, Osaka, Japan.
authors.forename: Tsunehiko
authors.initials: T
authors.lastname: Ikeda
mesh_terms: D000818:Animals; D051401:Aquaporin 4 / Q000378:metabolism*; D020346:Aquaporins / Q000378:metabolism*; D004487:Edema / Q000209:etiology; D008297:Male; D009409:Nerve Crush / Q000009:adverse effects / Q000379:methods*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009900:Optic Nerve / Q000378:metabolism* / Q000601:surgery; D009901:Optic Nerve Diseases / Q000209:etiology; D020221:Optic Nerve Injuries / Q000378:metabolism*; D017208:Rats, Wistar
chemical_list: C496032:Aqp4 protein, rat; C491637:Aqp9 protein, rat; D051401:Aquaporin 4; D020346:Aquaporins; D009419:Nerve Tissue Proteins