To investigate the regulation effect of astragalus polysaccharide on lung cancer-bearing mice in vivo immunity and tumor cell growth.

A total of 72 SPF-grade C57BL/6J mice were randomly divided into a model group（treated with an equal volume of normal saline by gavage）, a positive control group（treated with cisplatin 6.0 mg/kg via intraperitoneal injection）, a low-dose group（treated with astragalus polysaccharide solution 50 mg/kg by gavage, at a concentration of 1.0 mg/mL）and a high-dose group（treated with astragalus polysaccharide solution 100 mg/kg by gavage, at a concentration of 1.0 mg/mL）, with 18 mice in each group. The tumor volume, tumor mass, tumor inhibition rate, T lymphocyte count in peripheral blood and Survivin protein expression in tumor tissues were compared among the groups 14 days after modeling. Flow cytometry was used to detect the staging distribution of tumor cells in the tumor tissues of mice in each group.

Compared with those in the model group, the tumor volume and tumor mass in the positive control, low-dose and high-dose groups were all significantly lower（P<0.05）. Specifically, the tumor volume and tumor mass in the positive control group were significantly lower than those in the low-dose and high-dose groups（P<0.05）, while the tumor inhibition rate was significantly higher（P<0.05）. Furthermore, the tumor volume and tumor mass in the high-dose group were lower than those in the low-dose group（P<0.05）, and the tumor inhibition rate was higher（P<0.05）. In terms of peripheral blood, the levels of CD4⁺ and CD4⁺/CD8⁺ in the low-dose and high-dose groups were higher than those in the model and positive control groups（P<0.05）, while the CD8⁺ level was lower（P<0.05）. Additionally, the levels of CD4⁺ and CD4⁺/CD8⁺ in the high-dose group were higher than those in the low-dose group（P<0.05）, and the CD8⁺ level was lower（P<0.05）. Regarding Survivin protein expression in tumor tissues, the scores in the positive control, low-dose and high-dose groups were all lower than those in the model group（P<0.05）. Notably, the Survivin protein expression in the positive control group was lower than that in the low-dose and high-dose groups（P<0.05）, and the expression in the high-dose group was lower than that in the low-dose group（P<0.05）. Finally, the proportions of S-phase cells in tumor tissues were higher in the positive control, low-dose and high-dose groups compared to those in the model group（P<0.05）. Specifically, the proportion of S-phase cells in the positive control group was higher than that in the low-dose and high-dose groups（P<0.05）, and the proportion in the high-dose group was higher than that in the low-dose group（P<0.05）.

Astragalus polysaccharide can regulate the immune function and reduce the expression of Survivin protein in the treatment of lung cancer-bearing mice, thereby inhibiting the growth of tumor cells.