Abstract:The mechanism of the inhibitory effect of Eucheuma polysaccharides on the proliferation of H22 hepatocellular carcinoma cells (H22) in mice was investigated in vivo. An animal tumor model was established and changes in tumor size and organ indices of the mice in all groups were observed during the experiments. The content of tumor-specific antibodies in serum were measured via ELISA assay. Meanwhile, the proportions of T-cell subsets in thymus, spleen, peripheral blood, and solid tumors were detected by flow cytometry, and the cell cycle status of solid tumor cells was analyzed by hematoxylin-eosin staining and propidium iodide single staining. The results showed that administration of 600 mg/(kg?d) Eucheuma polysaccharides could significantly inhibit tumor growth, effectively protect the thymus and spleen, significantly enhance the development of CD4+ T cells in the thymus (p<0.05), and significantly increase the content of tumor-specific antibodies in serum (p<0.05) and the proportion of T cell subsets in blood (p<0.05). In addition, the tumor-infiltrating lymphocytes in both the polysaccharide and model groups were mainly CD8+ T cells. However, the apoptosis rate of solid tumor cells in the polysaccharide group was significantly increased (p<0.05) compared to that of the model group. It was preliminarily concluded that Eucheuma polysaccharides could improve the antitumor effect significantly in tumor-bearing mice and allow CD8+ T cells to effectively inhibit the proliferation of H22 cells with the help of CD4+ T cells and tumor-specific antibodies.
