Effects of Vitamin E Derivative TMG on the Radiation Protector and Tumor Growth during Radiotherapy

Background: The purpose of this study is to evaluate the immunosuppressive and antioxidant effects of a novel radioprotective agent using the vitamin E derivative 2-(alpha-D-glucopyranosyl) methyl-2,5,7,8-tetramethylchroman-6-ol (TMG) and its effect on tumors, and to study its usefulness. Materials and Methods: In this study, C57BL/6NCrSlc mice were divided into four groups (control, TMG, radiation therapy [RT], and RT+TMG), using 10 mice in each group. In the TMG and 2 Gy+TMG groups, 500 mg/kg TMG was administered. Two groups (2 Gy and 2 Gy+ TMG) among RT and RT+TMG groups were irradiated with 2 Gy in a single fraction, while the other two groups (6 Gy and 6 Gy+TMG) were irradiated locally with 6 Gy in three fractions. Results and Discussion: TMG positively affected CD4+ and CD8+ T lymphocytes. Tumor volumes and growth inhibition rates were compared. In order to evaluate how TMG administration affected tumor growth, Ehrlich cancer cells were injected into the thigh of mice, and the tumor volume and growth suppression rate were compared. Not only RT but also TMG alone inhibited tumor growth. If RT conducted to the mice with TMG, TMG could increase the number of leukocytes, primarily that of lymphocytes. TMG also inhibited tumor growth in addition to RT. Tumor growth was significantly inhibited in the 6 Gy+TMG group. Conclusion: In conclusion, TMG exerted an immunopotentiating effect mainly by increasing the white blood cell numbers including that of lymphocytes. In addition to RT, TMG also inhibited tumor growth. Therefore, TMG is considered to be a useful radioprotective agent in radiotherapy without tumor growth induction.