Aqueous extract from aerial arts of Artemisia vestita, a traditional Tibetan medicine, reduces contact sensitivity in mice by down-regulating the activation, adhesion and metalloproteinase production of T lymphocytes

In the present paper. the effect of the aqueous extract from aerial parts of Artemisia vestita (AV-ext), a traditional Tibetan medicine, on ear contact sensitivity was examined. AV-ext significantly reduced the ear swelling when administered during the induction phase of picryl-chloride (PCI)-induced ear contact sensitivity in mice. The extract also showed a dose-dependent inhibition on lymphocyte proliferation and IL-2 production in Con A-activated spleen cells. The proliferation inhibition was confirmed in the mixed lymphocytes reaction. Furthermore. the adhesion of the isolated spleen cells from PCI-sensitized mice to type IV collagen was significantly decreased in a dose-dependent manner by AV-ext. Such decrease was also Seen in Av-ext-treated Jurkat T cells and the T cells purified from above spleen cells. The purified spleen T cells from PCI-semitized mice produced more matrix metalloproteinase-9 (MMP-9) than naive T cells. and AV-ext remark-ably reduced MMP-9 production both in vivo and in vitro. These results suggest that AV-ext may alleviate contact sensitivity through blocking the activation of T lymphocytes and decreasing their localization to the inflammatory sites via down-regulating the potential of cell adhesion and metalloproteinase production. (C) 2004 Elsevier B.V. All rights reserved.