Abstract
Purpose::
To identify whether the green tea polyphenol (GTP) can have anti-inflammatory activities in human cornea by inactivation of T cells.
Methods::
20-200 µg/ml GTP was treated in human CD4+ T cells. In order to investigate the effects of GTP on proliferation or cytotoxicity of human CD4+ T cells, MTT assay was performed in GTP-treated human CD4+ T cells, and mRNA expressions of inflammatory cytokines were also investigated by RT-PCR. Inactivation mechanism of human CD4+ T cells by GTP was investigated by Western blot. Moreover, in-vitro corneal autoimmune disease model was established by coculture of human corneal cells with human CD4+ T cells, 20-200 µg/ml GTP was treated. The proliferation and inflammatory cytokines were assessed by MTT assay and RT-PCR.
Results::
GTP-treated CD4+ T cells showed inhibited cell proliferation, but did not showed any evidence of apoptosis. GTP-treated CD4+ T cells revealed significantly decreased expressions of inflammatory cytokines mRNA (IFN-α and -γ), and their molecular mechanism of GTP was related with MAPK signaling, especially in p38 downstream molecules. Coculture of human corneal cells and CD4+ T cells showed the similar proliferative aspects with direct treatment of GTP in CD4+ T cells. Moreover, GTP-treated corneal cells very resistance to inflammatory conditions.
Conclusions::
These results suggest that GTP can act as a not only anti-oxidant but also anti-inflammatory factor in human corneal cells, and their signaling mechanism is related with MAPK signaling. Thus the applications are expected in corneal inflammation and autoimmune diseases.
Keywords: antioxidants • cornea: basic science • inflammation