Tocopherol succinate: Modulation of antioxidant enzymes and oncogene expression, and hematopoietic recovery

Purpose: A class of naturally occurring isoforms of tocopherol (tocols) was shown to have varying degrees of protection when administered before radiation exposure. We recently demonstrated that α-tocopherol succinate (TS) is a potential radiation prophylactic agent. Our objective in this study was to further investigate the mechanism of action of TS in mice exposed to ⁶⁰Co γ-radiation. Methods and Materials: We evaluated the effects of TS on expression of antioxidant enzymes and oncogenes by quantitative RT-PCR in bone marrow cells of ⁶⁰Co γ-irradiated mice. Further, we tested the ability of TS to rescue and repopulate hematopoietic stem cells by analyzing bone marrow cellularity and spleen colony forming unit in spleen of TS-injected and irradiated mice. Results: Our results demonstrate that TS modulated the expression of antioxidant enzymes and inhibited expression of oncogenes in irradiated mice at different time points. TS also increased colony forming unit - spleen numbers and bone marrow cellularity in irradiated mice. Conclusions: Results provide additional support for the observed radioprotective efficacy of TS and insight into mechanisms.