(TOP) The relative change in Emax, an index of LV contractility, was computed as a percent of baseline values following I/R. A significant reduction in Emax occurred in the vehicle (n=10) and 4×104 KIU/kg APRO group (n=10). However, this depression in LV contractile function was ameliorated in the 2×104 KIU/kg APRO group (n=11). (MIDDLE) Plasma levels for the cytokine TNF were increased following I/R in both the vehicle and 2×104 KIU/kg APRO groups when computed as a percent change to reference control values. This I/R induced TNF release was abrogated in the 4 ×104 KIU/kg APRO group. (BOTTOM) Myeloperoxidase (MPO) content, as assessed by immunohistochemistry, was increased significantly from control values in all I/R groups when compared to reference control values. However, MPO levels were reduced from vehicle values in the 2 ×104 KIU/kg APRO group. Absolute values for these indices are provided in the Results. (*p<0.05 vs respective baseline/referent control; +p<0.05 vs vehicle; #p<0.05 vs 2 ×104 KIU/kg APRO)