Effects of Enbrel and low-dose TNF-α pretreatments on TNF-α concentrations in the process of IR. The mice of each group were sacrificed at indicated times, and the TNF-α levels of (A) serum and (B) liver homogenates were determined by ELISA. minR: minutes after reperfusion. Data are presented as mean ± SEM. (n = 5; *, P < 0.05; * *, P < 0.01). The data represent three separate experiments.