Objective To study the effects of adenosine 2A receptor activation on activation, proliferation, and toxicity of T lymphocytes stimulated by phytohemagglutinin (PHA) in vitro. Methods A model of activated T cells was established by stimulating the cells with PHA. Those T cells were treated with different concentrations of adenosine 2A receptors agonist (0.01 μmol/L, 0.1 μmol/L, 1 μmol/L, and 10 μmol/L CGS21680). The expressions of CD69, CD25 and proliferation of T cells were measured by fluorescent antibody stain and flow cytometry. ELISA method was used to detect IL-2 and INF-γ levels. Results All concentrations of CGS21680 significantly inhibited the expressions of CD25 and CD69 on PHA-stimulated T cells surface and proliferation of T cells （Plt;0.05， Plt;0.01）. IL-2 and INF-γ secreted by T cells were significantly suppressed, too （Plt;0.01）. Conclusion Activation of adenosine 2A receptor can effectively inhibit the activation, proliferation, and toxicity of T cells in vitro.
Objective To investigate the effects of adenosine 2A receptor (A2AR) activation on oxidative stress in small-forsize liver transplantation. Methods A rat orthotopic liver transplantation model was performed using 40% graft, 18 recipients were given intravenously saline (control group), CGS21680 (A2AR agonist, CGS21680 group) or ZM241385 (A2AR antagonist, CGS21680+ZM241385 group) randomly. Aspartate aminotransferase (AST), enzymatic antioxidants 〔superoxide dismutase (SOD); catalase (CAT); glutathione peroxidase (GSH-Px)〕, non-enzymatic antioxidants 〔ascorbic acid (AA); glutathione (GSH); α-tocopherol (TOC)〕 and lipid oxidant metabolites malondialdehyde (MDA) were measured and analyzed at 6 h after reperfusion. Results Compared with the control group and CGS21680+ZM241385 group, A2AR activation increased the activities of SOD and GSHPx (Plt;0.05), reduced the productions of AST and MDA (Plt;0.05), increased the levels of AA, GSH and TOC (Plt;0.05) in CGS21680 group. But there was no significant change in CAT activity (Pgt;0.05) among 3 groups. Conclusions A2AR activation improves the antioxidant enzyme activities, promotes the production of antioxidants, and slowes down the increase in MDA level, depresses of the increase in AST activity. A2AR activation suppresses oxidative damage and increases the antioxidant capacity which in turn minimizes their harmful effects of ischemia-reperfusion in small-for-size liver transplantation.