本文主要研究龙须菜酸性多糖（GLSPs）对H22荷瘤小鼠的肿瘤抑制作用。通过流式细胞术检测GLSPs对小鼠体内肿瘤细胞的细胞凋亡和细胞周期的影响；MTT法检测GLSPs对荷瘤小鼠脾淋巴细胞增殖能力和NK细胞杀伤活性的影响；组织病理学方法检测GLSPs对荷瘤小鼠肿瘤和免疫器官（脾脏、胸腺）的影响。结果显示，GLSPs能够促进荷瘤小鼠体内H22肝癌细胞凋亡，显著抑制肿瘤生长。以200 mg/(kg?d)和600 mg/(kg?d) GLSPs灌胃管理荷瘤小鼠28 d，小鼠的平均体积抑瘤率分别为84.65%和94.58%。免疫学试验显示，GLSPs能够明显改善荷瘤小鼠脾脏肿大和胸腺萎缩的组织病变情况，增强荷瘤小鼠免疫器官的免疫功能，同时能够有效调节荷瘤小鼠白细胞和淋巴细胞的激增，显著增强荷瘤小鼠由ConA和LPS诱导的T、B细胞的增殖能力，提高脾NK细胞的杀伤活性，多方面提高荷瘤小鼠机体的免疫水平，提示GLSPs通过免疫调节作用达到体内抗肿瘤效果。

In this study, the inhibitory effect of an acid polysaccharide from Gracilaria lemaneiformis (GLSPs) on H22-bearing mice was investigated. The influence of GLSPs on the cell cycle and apoptosis of tumor cells in vivo was studied using flow cytometry. The effect of GLSPs on splenetic lymphocyte proliferation and killing activity of NK cells in tumor-bearing mice were determined by MTT assay. The tissue pathological detection of the immune organs (spleen and thymus) in mice was performed. The results showed that apoptosis of H22 hepatoma cells in mice was promoted by GLSPs, and tumor growth was remarkably inhibited. Intragastric administration of GLSPs at 200 mg/(kg·d) and 600 mg/(kg·d) in tumor-bearing mice for 28 days resulted in an average inhibition rate of tumor volume of 84.65% and 94.58%, respectively. Immunological tests in tumor-bearing mice showed that pathological changes, including splenic enlargement and thymic atrophy, were significantly improved, and the function of the immune organs was reinforced. Moreover, the drastic increase of leukocytes and lymphocytes in the blood of tumor-bearing mice was effectively regulated, while the proliferation of T and B cells induced by ConA and LPS as well as the killing activity of NK cells were significantly improved. Thus, the immunity of tumor-bearing mice was enhanced through different mechanisms. These results indicate that GLSPs have anti-tumor effects in vivo via immunomodulation.

国家自然科学基金项目（31271975）