Objective: To study the effects of Liuyueqing polysaccharides on immunological function and p53

B cell lymphoma/leukemia-2 (Bcl-2)

Bcl-2 assaciatid X protein(Bax) oncoproteins expression in S180 tumor-bearing mice. Method: Fifty mice were inoculated subcutaneously with S180 cell in right axilla. Twenty-four h after inoculation

these mice were randomly divided into 5 groups:tumor model group (NS 20 mL·kg-1·d-1)

cyclophosphamide (CTX) group (0.02 g·kg-1·d-1) and high

medium

low-doses of Liuyueqing polysaccharides-treated groups (1.2

0.6

0.3 g·kg-1·d-1 ). Except that the cyclophosphamide group subjeced to intraperitoneal injection

other groups were given intragastric administration with drugs for 10 days. 24 h after last dose of drug

the inhibitory rate of transplantable tumor in mice was observed. Thymus and spleen were culled and weighed

indexs of thymus and spleen were calculated.Proliferated ability of spleen lymphocyte was assayed by MTT method. The phagocytized ability of enterocoelia macrophage was assayed by neutral red method. The oncoproteins expression of p53

Bcl-2 and Bax in the tumor tissue were studied by immunohistochemistry. Result: The inhibitory rate of high dosage of Liuyueqing polysaccharides (1.2 g·kg-1·d-1) was 38%. Compared to tumor model group

the indexes of thymus in each dose group were increased significantly (P<0.05). The indexes of spleen

proliferated ability of spleen lymphocyte and the phagocytized ability of enterocoelia macrophage in high

medium-doses groups were increased significantly (P<0.01 or P<0.05). The oncoproteins expressions of p53 in each dose group were not significantly different. The oncoproteins expression of Bcl-2 in high-dose group was decreased significantly (P<0.05). The oncoproteins expression of Bax in high-dose group was increased significantly (P<0.05). Conclusion: Liuyueqing polysaccharides has significant antitumor effect on S180 tumor-bearing mice. Enhancing the immunological function

down-regulation of Bcl-2 oncoproteins expression and up-regulation of Bax oncoproteins expression might be the main mechanisms of antitumor effect on S180 tumor-bearing mice.