六月青多糖对S180荷瘤小鼠免疫功能及p53, Bcl-2, Bax表达的影响

目的:探讨六月青多糖对S180荷瘤小鼠免疫功能及凋亡基因p53,B细胞淋巴瘤/白血病-2(Bcl-2),多肽抗原(Bax)表达的影响.方法:将50只小鼠于右腋皮下接种S180腹水肿瘤细胞建立S180荷瘤模型,造模24 h后随机分为5组:模型(生理盐水20 mL·kg-1·d-1)组,环磷酰胺(0.02 g·kg-1·d-1)组,六月青多糖高、中、低剂量(分别为1.2,0.6,0.3 g·kg-1·d-1)组.除环磷酰胺组隔天ip给药外,余均ig给药10 d.停药24 h后检测荷瘤小鼠抑瘤率、胸腺系数和脾脏系数；MTT法检测ConA刺激脾淋巴细胞转化功能；中性红法检测腹腔巨噬细胞吞噬功能；免疫组织化学法检测肿瘤组织中p53,Bcl-2,Bax蛋白.结果:六月青多糖高剂量(1.2 g·kg-1·d-1)抑瘤率达38％；与模型组比较,六月青多糖各剂量组胸腺系数显著增高(P＜0.05),高、中剂量组脾脏系数、脾淋巴细胞刺激指数和腹腔巨噬细胞吞噬功能显著增高(P＜0.01或P＜0.05)；六月青多糖各剂量组p53表达无明显差异；高剂量组Bcl-2表达显著减弱(P＜0.05)而Bax表达明显增强(P＜0.05).结论:六月青多糖能抑制小鼠S180肿瘤生长,其机制与增强S180荷瘤小鼠免疫功能、下调Bcl-2蛋白及上调Bax蛋白的表达有关.

Effects of Liuyueqing Polysaccharides on Immunological Function and p53, Bcl-2, Bax Oncoproteins Expression in S180 Tumor-bearing Mice

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.