Abstract: The protective effect of a kind of purified polysaccharides extracted from Radix of Phytolacca acinosa Roxb, with a molecular weight of 10 KDa, on hematopoiesis was investigated.Average survival time of mice treated with cyclophosphamide (CY) 300 mg/kg once alone was 13.3±7.2 d (n = 7) however, average survival time of mice treated with CY 300 mg/kg in com-bination with PAP-1 10 mg/kg, 3 times/wk was 36.7±16.4 d (n = 7, P<0.01). PAP-1, ip had benefi-cial effect on the recovery of the CY induced decrease of peripheral leukocyte number, and the nu-cleated bone marrow cell(BMC)number and [³H]TdR uptaken by BMC induced by rmGM-CSF in S180 bearing mice treated with CY, In mice, after the first ip treatment with CY 100 mg/kg on d7, the peripheral leukocyte number decreased on d9 and recovered to normal level about d13 to d15. Such recovery was accelerated by administrating PAP-1, 10 mg/kg, 3 times/wk. A significant in-crease of the activity to form colony in spleen(colony-forming unit in spleen, CFU-S8, CUF-S12 in mice irradiated with 550 rad ⁶⁰Co γ-rays and an enhancement of proliferative response of BMC to rm GM-CSF treated with PAP-1, 10 mg/kg, 3 times/wk, ip were observed.After PAP-1, 10 mg/kg, ip once, a significant increase in the number of peripheral blood leukocytes and a rise in the serum of colony stimulating factor (CSF) were also confirmed.The types of CSF in serum were M-CSF and other hematopoietic growth factors, which were confirmed by using McAb of IL-3, GM-CSF and PcAb of M-CSF. These beneficial effects of PAP-1 on hematopoiesis may be related to its activityinducing CSFs and other hematopoietic growth factors and warrant further evaluation of its use-fulness.

Key words: Phytolacca acinosa, Polysaccharides, Cyclophosphamide, Colony-forming unit in spleen(CFU-S), Colony stimulating factors, Monocolonal antibody, Polycolonal antibody