title: Comparison of radiation-induced reactive oxygen species formation in adult articular chondrocytes and that in human peripheral T cells: possible implication in radiosensitivity.
abstract: Previously, we examined the formation of reactive oxygen species (ROS) in T lymphocytes following 5 Gy of irradiation. Using a CCD camera system, we monitored fluorescence in T lymphocytes loaded with the succinimidyl ester of dichlorodihydrofluorescein diacetate (H2DCFDA), which is non-fluorescent until oxidized by ROS. We found that ROS formation occurred immediately after irradiation, continued for several hours, and resulted in oxidative DNA damage. Therefore, the origin of the hyper-radiosensitivity of T lymphocytes seemed to be the high production of ROS in the mitochondrial DNA following irradiation. In this study, we examined radiation-induced ROS formation in adult articular chondrocytes, which were demonstrated to be highly resistant to apoptosis in our previous study. We found that ROS formation was actually scarcely seen after irradiation of up to 20 Gy in these cells. Therefore, the origin of the great difference of radiosensitivity between T lymphocytes and adult articular chondrocytes is considered to lie in the degree of ROS formation following irradiation, with this difference possibly resulting from the scavenging acuity of these two kinds of normal tissue cells for free radicals including hydroxyl radicals.
authors.affiliation: Department of Radiology, Kochi Medical School, Oko-cho, Nankoku-shi, Kochi-Prefecture 783-8505, Japan. ogaway@kochi-ms.ac.jp
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Ogawa
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Takahashi
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Michio
authors.initials: M
authors.lastname: Toda
authors.forename: Akihito
authors.initials: A
authors.lastname: Nishioka
authors.forename: Shinji
authors.initials: S
authors.lastname: Kariya
authors.forename: Harumichu
authors.initials: H
authors.lastname: Seguchi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Shoji
authors.initials: S
authors.lastname: Yoshida
mesh_terms: D019902:Chondrocytes / Q000378:metabolism* / Q000528:radiation effects; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000378:metabolism; D011836:Radiation Tolerance / Q000528:radiation effects*; D017382:Reactive Oxygen Species / Q000378:metabolism* / Q000528:radiation effects; D013601:T-Lymphocytes / Q000378:metabolism* / Q000528:radiation effects
chemical_list: D017382:Reactive Oxygen Species