Rosiglitazone treatment increased dual-specificity phosphatase 8 (DUSP8) expression at both protein and messenger RNA (mRNA) levels. (A) Western blot and densitometric analysis of DUSP8 and β-actin expression (n=4 each group, *P<0.05 versus 3 hours of reperfusion with dimethyl sulfoxide (DMSO) group, +P<0.05 versus 24 hours of reperfusion with DMSO group). Dual-specificity phosphatase 8 was significantly upregulated in the cortex after 3 and 24 hours. (B) Comparison of the effect of rosiglitazone on DUSP8 mRNA expression in mouse brains after 3 hours of reperfusion with DMSO and rosiglitazone treatments (n=4 each group, *P<0.05 versus DMSO treatment group). (C) Phosphatase activity assay of ischemic brains treated with rosiglitazone (R3 and R24) and DMSO (D3 and D24) after 3 and 24 hours of reperfusion. The rosiglitazone-treated samples after 3 hours of reperfusion showed a significant increase in phosphatase activity compared with non-treated ischemic brains (n=4 each group, *P<0.05 versus DMSO-treated group). O.D., optical density; sh, sham; 18S, control mRNA.