The Radioprotective Effect of 5-thio-D-glucose on Normal Tissues in Vivo

The radioprotective effect of 5-thio-D-glucose (5-TG, NSC 204984) on normal tissues of mice was investigated. The LD50 of 5-TG in A/J mice injected intraperitoneally (i.p.) is 5.5 g/kg. The animals were injected i.p. with saline or 5-TG followed by whole-body irradiation or localized irradiation of the foot. Mice injected with 1.5 g/kg of 5-TG were protected from gastrointestinal or bone marrow death following whole-body irradiation by a dose modification factor (DMF) of 1.1--1.3. The same dose of 5-TG protected mice from foot skin damage between days 0 and 40 post-irradiation by a DMF of 1.3, and from late foot deformity during days 60 to 90 post-irradiation by a DMF of 1.2. Foot skin reactions indicated that 5-TG provided maximal radioprotection up to 4 hours after an intraperitoneal injection. We have previously reported that 5-TG selectively kills and radiosensitizes hypoxic cells. Consequently, it may be possible to use this compound as an adjuvant to radiotherapy in order to kill or radiosensitize hypoxic cells and to radioprotect normal tissue.