Fifty male SD rats were randomly divided into control group， model group， low， medium and high doses of Tanreqing Injection groups （n =10）. The OSAHS rat models were established by alternating cycles of hypoxia（6%－8% O₂ in N₂ for 40 s） and normoxia （2l% O₂ in N₂ for 80 s） in model group， low， medium and high doses of Tanreqing Injection groups， 8 h every day. The rats in low， medium and high doses of Tanreqing Injection groups were given 0.9， 1.8 and 3.6 mL·kg^－1 Tanreqing Injection by gavage， while the rats in control group and model group were given equal volume of normal saline. The spleen indexes and thymus indexes of the rats in various groups were measured after 14 d of continuous administration. MTT assay was used to detect the proliferation activities of T lymphocytes of the rats in various groups. Flow cytometry was used to detect the percentages of different T lymphocyte subsets in peripheral blood of the rats in various groups. ELASA was used to detect the serum levels of tumor necrosis factor-α （TNF-α）and interleukin- 6（IL-6） of the rats in various groups.

Compared with control group， the spleen index， the thymus index， the proliferation activity of T lymphocytes， the percentage of CD4⁺ T lymphocytes， the CD4⁺/CD8⁺ T lymphocyte ratio of the rats in model group were significantly decreased （P<0.05）， while the percentage of CD8⁺ T lymphocytes， the levels of serumTNF-α and IL-6 were significantly increased （P<0.05）. Compared with model group， the spleen indexes， the thymus indexes， the proliferation activities of T lymphocytes， the percentages of CD4⁺ T lymphocytes， the CD4⁺/CD8⁺ T lymphocytes ratios of the rats in low， medium and high doses of Tanreqing Injection groups were significantly increased（P<0.05 ），and the percentage of CD8⁺ T lymphocytes and the levels of serumTNF-α and IL-6 in the peripheral blood were significantly increased （P<0.05）. Compared with low dose of Tanreqing Injection group， the proliferation activity of T lymphocytes in the high dose of Tanreqing Injection group was significantly increased （P<0.05）， and the levels of TNF-α and IL-6 in serum of the rats in medium and high doses of Tanreging Injection groups were significantly decreased （P<0.05）.

Tanreqing Injection can protect the rats with OSAHS by regulating the balance of T lymphocyte subsets and inhibiting inflammation response.