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 ± 7.2d(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± 16.4d(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[3￣H]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-1,10mg/kg, 3 times/wk.A significant in-crease of the activity to form colony in spleen(colony-forming unit in spleen, CFU-S_8, CUF-S12) in mice irradiated with 550 rad 6O￣Co γ-rays and an enhancement of proliferative response of BMC to rmGM-CSF treated with PAP-1,10mg/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.
