Objective

To observe the effects of Radix Glycyrrhizae polysaccharide on regulatory T cells (Treg) in spleen and lymphocyte transformation ratio in tumor-bearing mice so as to explore the mechanisms of its immunoregulatory function.
Methods

Fifty BALB/c mice were randomly divided into normal group, untreated group, cyclophosphamide group, Radix Glycyrrhizae polysaccharide group and Radix Glycyrrhizae polysaccharide plus cyclophosphamide group. Except normal group, mice were subcutaneously implanted H22 tumor cells in the right axillary region. After 24 h, mice in normal and untreated group were subcutaneously injected with physiological saline, while mice in the cyclophosphamide group were intraperitoneally injected with cyclophosphamide and mice in Radix Glycyrrhizae polysaccharide group were subcutaneously injected with polysaccharide. Fourteen days later, Treg cells of spleen were detected by flow cytometry and lymphocyte transformation ratio was detected by methyl thiazolyl tetrazolium method.
Results

The proportion of Treg cells was significantly higher in the untreated group than in the normal group, and was lower in the Radix Glycyrrhizae polysaccharide group than in the untreated group (P<0.01). Lymphocyte transformation ratio in the Radix Glycyrrhizae polysaccharide group was higher than that in the cyclophosphamide group. There was no interaction between Radix Glycyrrhizae polysaccharide and cyclophosphamide.
Conclusion

Radix Glycyrrhizae polysaccharide can regulate the cellular immunity disorders of tumor-bearing mice by decreasing proportion of Treg cells and increasing spleen lymphocyte transformation ratio.

Key words: Glycyrrhiza, T-lymphocytes, Regulatory, Liver neoplasms, Experimental, Mice