title: Long-term sequential changes of radiation proctitis and angiopathy in rats.
abstract: The purpose of the present study was to establish an experimental rat model for late radiation proctitis, and to examine the assessment strategy for late radiation proctitis. A total of 57 Wistar rats were used. Fourty-five of the rats were exposed to selective rectal irradiation with a single fraction of 25 Gy. These rats were sacrificed at the 4(th), 12(th), 24(th), and 37(th) week following irradiation. The remaining 12 rats comprised the control group without irradiation. The rectal mucosa of each rat was evaluated macroscopically and pathologically. The number of vessels in the rectal mucosa was counted microscopically. In addition, the vascular stenosis was evaluated. In the results, the degree of clinical and macroscopic findings decreased following acute proctitis and developed later. In the pathological examination, mucosal changes and microangiopathy were followed up, as well. The absolute number of vessels in the rectum was the greatest at the 12(th) week following irradiation and was the lowest in the control group. The severity of the microangiopathy was also well evaluated. To conclude, we established an animal experimental model of late radiation proctitis, and also established an assessment strategy to evaluate objectively the severity of late radiation proctitis with focusing on microangiopathy using an animal experimental model. This model can be used as an animal experimental model of radiation-induced microangiopathy.
authors.affiliation: Department of Radiology, Hyogo College of Medicine, Nishinomiya City, Hyogo, 663-8501 Japan. h-doi@hyo-med.ac.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Doi
authors.forename: Norihiko
authors.initials: N
authors.lastname: Kamikonya
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Takada
authors.forename: Masayuki
authors.initials: M
authors.lastname: Fujiwara
authors.forename: Keita
authors.initials: K
authors.lastname: Tsuboi
authors.forename: Hideharu
authors.initials: H
authors.lastname: Miura
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Inoue
authors.forename: Masao
authors.initials: M
authors.lastname: Tanooka
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Shikata
authors.forename: Takeshi
authors.initials: T
authors.lastname: Kimura
authors.forename: Tohru
authors.initials: T
authors.lastname: Tsujimura
authors.forename: Shozo
authors.initials: S
authors.lastname: Hirota
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D058729:Peripheral Arterial Disease / Q000473:pathology*; D011349:Proctitis / Q000473:pathology*; D011832:Radiation Injuries / Q000473:pathology*; D011833:Radiation Injuries, Experimental / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar; D012007:Rectum / Q000473:pathology* / Q000528:radiation effects*