Radioprotective and Anticancer Efficacies of Ganoderma Lucidum in a Mouse Tumor Model

Background: Radiation dose is limited by deleterious nontarget effects, such as immunosuppression, necessitating the development of safe radioprotectants. In this study, we examined the radioprotective and anticancer efficacies of the traditional medicinal mushroom Ganoderma lucidum (GL) in a mouse xenograft tumor model. Methods: An aqueous extract was prepared from raw GL and administered by intraperitoneal injection. For the assessment of antitumor efficacy, ICR mice were inoculated with Sarcoma 180 cells and tumor growth (size and weight) compared among control (no treatment), GL alone, radiation alone, and GL plus radiation groups. For the assessment of the protection of the immune system, ICR mice received whole-body irradiation at 2 Gy for 2 weeks or longer with or without intraperitoneal GL administration, and changes in leukocyte, lymphocyte, and monocyte counts were measured. To examine the antioxidant efficacy of GL, ICR mice received whole-body radiation at 2 Gy with or without GL and plasma antioxidant activity measured by the luminol method. Results: Finally, the effects of GL on T helper (CD4-positive) and natural killer (CD8-positive) cell numbers were measured in C57BL mice by flow cytometry. GL administration alone suppressed tumor growth and the tumor-associated increase in lymphocyte and monocyte numbers. In addition, GL enhanced plasma antioxidant activity as well as both helper and natural killer T cell numbers in the presence and absence of irradiation. Conclusion: Collectively, these results demonstrate the antitumor and radioprotective efficacies of GL, which are likely mediated by protection against oxidative stress and preservation of immune cell populations.