Presentation The Protective Effects of Antioxidant TEMPOL to the Carbon Ion Beam Induced Muscle Fibrosis in Mouse Leg

Ueno, Megumi  ,  Ogawa, Yukihiro  ,  Nakamura, Mizuki  ,  Nakanishi, Ikuo  ,  Ken-ichiro, Matsumoto

The irradiating an aqueous sample with the heavy (carbon) ion beam induces generation of free radicals. The generation of free radicals can make oxidative damages to the irradiated tissues. The free radical induced tissue injury may become a problem in the future radiotherapy in which a high- dose and single/low fractionated irradiation protocol is probably be proposed. Fibrosis of normal tissues often accompanies in a radiation treatment of cancer. It was reported that single radiation to local irradiation to flank of a mouse caused shortening the leg due to fibrosis of the muscle. The shorting length of the irradiated leg can be an index of the fibrosis, i.e. the tissue damage. In this study, the effects of an anti-oxidant, TEMPOL (4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl), against radiation induced fibrosis of mouse leg muscle was investigated. Female C3H mice were fed on drinking water containing 0 or 30 mM TEMPOL from 1 week before irradiation to the end of the observation period (for around 300 days). The left hind leg of anesthetized mouse was irradiated with 32 Gy single dose of 290 MeV/nucleon carbon ion beam with 6 cm SOBP condition. Using 50 or 117 mm thickness binary filter, a low or high LET part of the carbon ion beam was irradiated. The lengths of both hind legs of the mice were measured using a digital caliper every one week after irradiation. The non-irradiated right leg was as the control. The level of shortening of the irradiated leg was severer with the higher LET (117 mm binary filter) irradiation compare to the lower LET (50 mm binary filter). The appearance of the skin inflammation on the irradiated leg looked milder in TEMPOL drinking groups. The results suggest that TEMPOL can protect and/or mitigate carbon ion beam induced tissue damages. The TEMPOL has been known as a superoxide dismutase mimic. It was inferred that the superoxide might be a main trigger and/or attacker in a process of the biological damages induced by the carbon ion beam.
15th International Congress of Radiation Research (ICRR 2015)

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