To study the effects of shikonin,which is a kind of monomer of Chinese traditional herbs with cooling blood and detoxification,on the function of abnormally activated T lymphocytes and related signal transduction pathways in the pathological state of psoriasis in vitro cell model.Methods:Jurkat E6-1 T lymphocytes were activated with phorbol ester and ionomycin,and shikonin at a concentration of 0.5-2 μg/mL was applied to the cells.T lymphocyte proliferation ability was detected by CCK-8 method.The flow cytometry was used to detect the expression of CD69 and the change of intracellular free calcium concentration (［Ca2+］i).The enzyme-linked immunosorbent assay (ELISA) was used to detect the release of interleukin-2 (IL-2),interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α); q-PCR and Western blot were used to observe the effects of nuclear transcription factor mRNA and protein expression.Results:Different concentrations of shikonin can significantly inhibit cell proliferation,CD69 expression and Th1 cytokine secretion; both can effectively reduce the content of ［Ca2+］i and protein kinase C (PKC) phosphorylated protein,significantly reduce nuclear transcription factor NF-The expression of AT mRNA down-regulates the mRNA and protein expression of c-Jun and inhibit the expression of NF-κB protein.All the above indicators had a certain dose-effect relationship.Conclusion:Shikonin can exert immunoregulatory effects by inhibiting the function of over-activated T lymphocytes,and provide experimental evidence for the mechanism and application prospect of shikonin in the treatment of psoriasis.