Abstract: AIM: To investigate the protective effect of purified fraction 1 polysaccharide extracted from Rheum tanguticum on irradiation-induced immune damage in mice. METHODS: Kunming mice were randomly divided into five groups: normal group (NC), irradiation control group (IC), RTP1 low dose group (200 mg/kg), middle dose group (400 mg/kg) and high dose group (800 mg/kg).The mice in RTP1 group were poured through gastic route by RTP1 for 14 d, the mice in NC and IC group were given by 0.9% sodium chloride solution through the same way. The mice in all groups except NC group were irradiated with 2.0 Gy ⁶⁰Co γ-ray on the fourteenth day. Immune index of non-specific immune function, cellular immunity and humoral immunity were detected at the 24th hour after radiation. RESULTS: Compared with IC group, the spleen index, thymus index, the rate of carbon clearance, phagocytic function of macrophage, lymphocytes proliferation, hemolysin value of blood serum and NK activity in RTP1 groups were increased markedly (P＜0.05 or P＜0.01). CONCLUSION: RTP1 has an obvious protective effect on damage in γ-ray radiated mice.

Key words: Polysaccharide of Rheum tanguticum, Immune function, Radiating damage, ⁶⁰Coγ Ray