Objective: To study the effect of dihydroartemisinin on immune-regulation of T-lymphocytes from peripheral blood in adjuvant-induced arthritis (AA) rats. Method: Sprague Dawley rats with a mean weight of 160-180 g were randomly divided into 6 groups

including normal group

AA model group

methotrexate group(1 mg · kg-1)

dihydroartemisinine high-dose

medium-dose and low-dose group(11.2

5.6

2.8 mg ·kg-1 ). The rat adjuvant arthritis model were induced. The drugs were administrated by ig for consecutive 28 days after inducing AA model. T-lymphocyte in peripheral blood was detected by flow cytometry

and the levels of interferon-γ(INF-γ) and interleukin-4(IL-4) in serum were measured by ELISA on AA animal model treated bydihydroartemisinin. Result: Compared with the normal group

the ratio of CD4+T

CD4+T/ CD8+T from peripheral blood in model group and IFN-γ levels in serum were significantly increased(P<0.01)

and the levels of IL-4 were significantly decreased(P<0.01).In high and medium dose group

the percentages of CD4+T was (34.81±3.80)%

(34.92±5.14)%

the ratio of CD4+T/ CD8+T was 2.21±0.43

2.27±0.48

respectively

compared with model group they were significantly decreased(P<0.05

P<0.01).In dihydroartemisinin three dose group

the levels of INF-γ were (15.90±2.05)

(16.27±2.11)

(18.15±2.15) ng ·L-1

and the levels of IL-4 were (40.21±4.89)

(40.04±4.56)

(34.81±4.02) ng ·L-1

compared with the model group they had significant changes(P<0.01).For IL-4

dihydroartemisinin’s effect showed a dose-dependent manner at concentrations between 2.8-5.6 mg · kg-1(P<0.05). Conclusion: Dihydroartemisinin could effectively improve the immunity mess in T-lymphocytes from peripheral blood in AA rats

which is useful for curing rheumatoid arthritis.