Objective  To investigate the influence of Fuzheng Xiaoji Decoction on tumor growth and immune function of tumor-bearing mice with lung cancer.

  Methods  A total of 30 specific pathogen free (SPF) C57BL/6 male mice were selected, of which 6 normal mice were included in control group, and the other 24 tumor-bearing model mice with lung cancer by subcutaneous injection were randomly divided into model group (treated with the same dose of normal saline), low dose group (treated with 125 mg/kg Fuzheng Xiaoji Decoction), medium dose group (treated with 250 mg/kg Fuzheng Xiaoji Decoction) and high dose group (treated with 500 mg/kg Fuzheng Xiaoji Decoction), with 6 mice in each group. The tumor volume was observed and the growth curve was drawn. Tumor weight was recorded and tumor inhibition rate was calculated. Thymus index and spleen index were recorded. Lymphocyte transformation and killing activity of specific cytotoxic T lymphocyte (CTL) were detected. The numbers of CD4⁺ T cells and CD8⁺ T cells in peripheral blood were detected by flow cytometry. Levels of serumtumor necrosis factor-α (TNF-α) and interleukin-2 (IL-2) in mice were detected by enzyme-linked immunosorbent assay.

  Results  On the 20th, 24th and 28th day after administration, the tumor volumes of mice in different doses of Fuzheng Xiaoji Decoction groups were significantly smaller than those in the model group, and the tumor volume of the high dose group was smaller than that of the low dose group and the medium dose group (P < 0.05). The tumor weights of mice in different doses of Fuzheng Xiaoji Decoction groups were significantly lower than that in the model group, while the tumor inhibition rates were significantly higher than that in the model group(P < 0.05). Compared with the control group, the spleen index, thymus index, the number of CD4⁺ T cells, value of CD4⁺/CD8⁺, lymphocyte transformation, killing activity of CTL as well as serum TNF-α and IL-2 in the model group reduced significantly, while the number of CD8⁺ T cells increased significantly (P < 0.05). Compared with the model group, the spleen index, thymus index, the number of CD4⁺ T cells, value of CD4⁺/CD8⁺, lymphocyte transformation, killing activity of CTL as well as serum TNF-α and IL-2 in the middle dose and high dose groups increased significantly, while the number of CD8⁺ T cells decreased significantly (P < 0.05).

  Conclusion  Fuzheng Xiaoji Decoction can inhibit tumor growth and improve immune function of tumor-bearing mice, which is related to its promoting effect on CD8⁺ T cells to secrete IL-2 and TNF-α.