Inhibition of TPA-induced edema and MPO activity by phytosphingosine. The inner and outer surfaces of ears of ICR mice were treated with TPA (10 nmoles in acetone) and then vehicle (ethanol:propylene glycol, 7:3), aspirin (20 µmoles), phytosphingosine (PS, 20 µmoles), or troglitazone (TGZ, 20 µmoles). Edema was evaluated by measuring the weight of ears, and MPO activity was measured by the dianisidine-H2O2 assay. Data are presented as means ±SEM (n = 7). *Significant at P < 0.05.