title: Cell and Tissue Damage after Skin Exposure to Ionizing Radiation: Short- and Long-Term Effects after a Single and Fractional Doses.
abstract: Ionizing radiation is often used to treat progressive neoplasms. However, the consequences of long-term radiation exposure to healthy skin tissue are poorly understood. We aimed to evaluate the short- and long-term radiation damage to healthy skin of the same irradiation given either as single or fractional doses. C57BL/J6 mice were randomly assigned to one of three groups: a control and two exposure groups (5 Gy ×2 or 10 Gy ×1). The inguinal area was irradiated (6-MeV beam) 1 week after depilation in the treatment groups. Skin samples were evaluated macroscopically and histologically for up to 6 months after the final exposure. After anagen hair follicle injury by irradiation, hair cycling resumed in both groups, but hair graying was observed in the 10 Gy ×1 group but not in the 5 Gy ×2 group, suggesting the dose of each fractional exposure is more relevant to melanocyte stem cell damage than the total dose. On the other hand, in the long term, the fractional double exposures induced more severe atrophy and capillary reduction in the dermis and subcutis, suggesting fractional exposure may cause more depletion of tissue stem cells and endothelial cells in the tissue. Thus, our results indicated that there were differences between the degrees of damage that occurred as a result of a single exposure compared with fractional exposures to ionizing radiation: the former induces more severe acute injury to the skin with irreversible depigmentation of hairs, while the latter induces long-term damage to the dermis and subcutis.
authors.forename: Kahori
authors.initials: K
authors.lastname: Kinoshita
authors.forename: Hisako
authors.initials: H
authors.lastname: Ishimine
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Shiraishi
authors.forename: Harunosuke
authors.initials: H
authors.lastname: Kato
authors.forename: Kentaro
authors.initials: K
authors.lastname: Doi
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Kuno
authors.forename: Koji
authors.initials: K
authors.lastname: Kanayama
authors.forename: Kazuhide
authors.initials: K
authors.lastname: Mineda
authors.forename: Takanobu
authors.initials: T
authors.lastname: Mashiko
authors.forename: Jingwei
authors.initials: J
authors.lastname: Feng
authors.forename: Keiichi
authors.initials: K
authors.lastname: Nakagawa
authors.forename: Akira
authors.initials: A
authors.lastname: Kurisaki
authors.forename: Satoshi
authors.initials: S
authors.lastname: Itami
authors.forename: Kotaro
authors.initials: K
authors.lastname: Yoshimura
mesh_terms: D000818:Animals; D002196:Capillaries / Q000528:radiation effects; D020405:Dermis / Q000528:radiation effects; D004307:Dose-Response Relationship, Radiation; D042783:Endothelial Cells / Q000528:radiation effects*; D004817:Epidermis / Q000528:radiation effects; D018859:Hair Follicle / Q000528:radiation effects; D008297:Male; D008810:Mice, Inbred C57BL; D011839:Radiation, Ionizing; D012038:Regeneration; D012867:Skin / Q000473:pathology* / Q000528:radiation effects*; D050151:Subcutaneous Fat / Q000528:radiation effects; D013997:Time Factors