Effects of Vitamin E on the immune system and tumor growth during radiotherapy
Yeun-Hwa Gu1, Ki-Mun Kang2, Takenori Yamashita3, Jin Ho Song4
1 Department of Radiological Science, Faculty of Health Science, Junshin Gakuen University, Fukuoka, Japan
2 Department of Radiation Oncology, Gyeongsang National University School of Medicine and Gyeongsang National University Changwon Hospital, Changwon; Institute of Health Science, Gyeongsang National University, Jinju, Republic of Korea
3 Department of Radiological Science, Faculty of Health Science, Suzuka University of Medical Science, Suzuka, Mie, Japan
4 Department of Radiation Oncology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
Jin Ho Song
Department of Radiation Oncology, Seoul St. Mary's Hospital, Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 06591
Republic of Korea
Department of Radiological Science, Faculty of Health Science, Junshin Gakuen University, 1-1-1 Chikushigaoka, Minami-ku, Fukuoka 815-8510
Source of Support: None, Conflict of Interest: None
Purpose: The purpose of this study is to evaluate the effects of Vitamin E (VE) on the immune system and tumor growth during radiotherapy (RT) in mice model.
Methods: C57BL/6NCrSlc mice were randomly distributed in four groups (control, VE alone, RT alone, and VE + RT). In the VE and VE + RT groups, VE was administered in the diet at 500 mg/kg. Radiation was delivered at 2 Gy in a single fraction on the whole body or at 6 Gy in three fractions locally in the RT and VE + RT groups. Changes in leukocytes and T lymphocytes were counted and compared between the four groups. To evaluate the effects on tumor growth, Ehrlich carcinoma cells were injected into the thighs of mice, and tumor volumes and growth inhibition rates were compared.
Results: The number of leukocytes was increased in the VE group compared with that in the control group. The magnitude of leukocyte recovery after RT was also increased by VE. This change was affected largely by alterations in lymphocytes and monocytes rather than that in granulocytes. Both CD4+ and CD8+ T lymphocytes were positively affected by VE. The tumor growth was inhibited not only by RT but also by VE alone. If RT was delivered with VE, tumor growth was markedly inhibited.
Conclusion: VE could increase the number of leukocytes, primarily lymphocytes, even after RT was delivered. VE also inhibited the tumor growth in addition to RT. Thus, VE may be a useful radioprotective supplement in radiotherapy without inducing tumor growth.