Elm bark extract improves immunomodulation and ameliorates oxidative stress in irradiated mice

Background: Radiation therapy can result in side effects such as cellular and tissue inflammation and organ damage. Previously, elm bark (EB) extract has been reported to exert antioxidant and anti-inflammatory effects. In this study, we investigated whether EB administration could improve immunocompetence and ameliorate radiation-induced intestinal damage in irradiated mice.Methods: After exposure to radiation of 15 Gy, mice were orally administered with EB extract (0 mg/kg, 50 mg/kg, and 500 mg/kg body weight) every other day for 2 weeks, and there was a 2-week washout period. The proliferation of splenocytes and cytokine production of macrophage were measured as indices of immune activity, and histological grade and antioxidant levels in radiation-induced intestinal injury were measured.Results: Radiation exposure reduced the T-cell proliferation in splenocytes and the levels of interleukin-1β and interleukin-6 from macrophage at Week 2. The supplement of EB extract at low concentration (50 mg/kg body weight; EB-50) tended to enhance T-and B-cell proliferation in irradiated mice. The histological grades of the small intestine were induced by radiation exposure, whereas histological grade of the EB-50 group was lower than that of the irradiated control at Week 4. The EB-50 treatment reduced the level of glutathione at Day 5 and Week 2 and reduced myeloperoxidase activity at Week 4, suggesting that EB-50 may counteract the intestinal inflammation caused by radiation exposure.Conclusion: Our results indicate that EB extract (50 mg/kg body weight) protects against radiation damage, at least in part, by improving immunomodulation and ameliorating oxidative stress in irradiated mice