Abstract: AIM: To study the protective effects of purified fraction 1 of polysaccharide extracted from rheum tanguticum (RTP1) on radiation-induced hematopoietic damage in mice. METHODS: Male Kunming mice which were 6 week old 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 6.5 Gy ⁶⁰Co γ-ray on the fourteenth day. The 30 d survival rate of mice was observed. The number of white blood cell (WBC) and bone marrow cell (BMC), as well as the count of endo-genous splenic colony-forming-unit (CFU-S) were detected. DNA content of marrow was also measured.RESULTS: Compared with that of the IC group, 30 d survival rate, the number of WBC and BMC, the count of CFU-S and the DNA content of marrow were significantly higher with a dose- dependent manner. CONCLUSION: RTP1 could improve the hematopoietic recovery after irradiation.

Key words: Polysaccharide of rheum tanguticum, radiation damage, ⁶⁰Coγ ray;, Hematopoietic system