Abstract: Objective:To investigate the influence of panax notoginseng saponins (PNS) in the T lymphocyte subsets and hematopoietic function in the aplastic anemia model mice, and to elucidate the therapeutic mechanism of PNS in the aplastic anemia mice. Methods:Fifty mice were randomly divided into control group, model group, low dose of PNS group, medium dose of PNS group, and high dose of PNS group.The mice in low,medium,and high doses of PNS groups were intraperitoneally injected with 100, 200, and 400 mg·kg^-1PNS; the mice in control group and model group were intraperitoneally injected with normal saline of the same volume;lasted for 14 d. The body weights of the mice were measured and the spleen and thymus indexes were calculated after administration. Flow cytometry was used to detect the percentages of CD4⁺, CD8⁺T lymphocytes and the ratio of CD4⁺/CD8⁺T lymphocytes in the peripheral blood of the mice.The serum γ-interferon (INF-γ) and tumor necrosis factor-α(TNF-α) levels of the mice were determined by ELISA. The number of red blood cells (RBC), bone marrow mononuclear cells (BMCs), white blood cells (WBC), platelets (Plt) and the hemoglobin (Hb) level of the mice were measured by hematdogy analyzer. Results:Compared with control group, the body weight, the spleen index,the thymus index, the peripheral blood CD4⁺T lymphocyte percentage and the CD4⁺/CD8⁺T lymphocyte ratio of the mice in model group were significantly decreased (P<0.05); the number of RBC, BMCs, WBC, Pl tand the Hb level were significantly decreased(P<0.05); the peripheral blood CD8⁺T lymphocyte percentage and the serum INF-γ, TNF-α levels were significantly increased (P<0.05). Compared with model group, the body weights, the spleen indexes, the thymus indexes, the CD4⁺T lymphocyte percentages and the CD4⁺/CD8⁺T lymphocyte ratios of the mice in low, medium, and high doses of PNS groups were significantly increased (P<0.05); the number of BMCs, WBC, Plt and the level of Hb were significantly increased(P<0.05); the percentages of CD8⁺T lymphocytes and the levels of serum INF-γ and TNF-α of the mice were significantly decreased (P<0.05). Conclusion:PNS can improve the hematopoietic function of the aplastic anemia mice by regulating the balance of T lymphocyte subsets in a dose-dependent manner and inhibiting the release of INF-γ and TNF-α and increasing the levels of hematopoietic related factors.

Key words: aplastic anemia, panax notoginseng saponins, T lymphocyte subsets, spleen index, thymus index