Effects of glycyrrhizae and glycyrrhizic acid on cellular immunocompetence in low-dose γ-ray irradiated mice

Background: For both animals and human beings, it is important to prevent damage from ionizing radiation and to restore immunocompetence following irradiation. The present study was conducted to investigate the effects of glycyrrhizae (GL) and glycyrrhetinic acid (GA) on cellular immunocompetence in low dose γ-ray-irradiated mice. Methods: Six- to 8-week- old ICR strain' Crl:CD-1®-ICR (BR) strain male mice, bred in the Institute of Cancer Research, U.S.A., were chosen and divided into four groups. Group A was the normal control. Group B, the experimental control, received 1 Gy of whole body γ-ray irradiation. Groups C and D, the experimental groups, were treated with 500 mg/kg of GL (orally) and 5 mg/kg body weight of GA (i.p.), respectively, once a day, 5 days a week for 2 weeks after γ-irradiation. The tested mice were killed, at 6 different intervals to measure their leukocyte and differential counts. Cellular immunocompetence was measured by the ³H- thymidine uptake in each group. Results: One gray of γ-ray irradiation had evident inhibition on the leukocyte and differential counts and the cellular immunity of mice. GL and GA could help to restore the decreased leukocyte counts and the cellular immunocompetence in low dose γ-irradiated mice. Conclusion: GL and GA could help to restore decreased leukocyte counts and the cellular immunocompetence in low-dose γ-ray-irradiated mice.