Figure 4: Time course of burn depth progression in cold water-treated animals (controls; blue bars), as well as in animals treated with EPO500 45 min (light grey), EPO500 6 hrs (intermediate grey) or EPO2,500 45 min (dark grey) (A). Burn depth progression score: 1. epidermis; 2. superficial dermis; 3. intermediate dermis; 4. deep dermis; 5. muscle. Mean ± SEM; *p<0.05 vs. controls; n=7/group. Histology of dermis (B, D, F, H) and muscle (panniculus carnosus: C, E, G, I) at day 7 after burn with complete architectural destruction of dermis, skin appendages and muscle in cold water-treated animals (B, C). Note the partial preservation of both, skin appendages (D) and muscle (E), in animals treated with EPO500 45 min, indicating that burn progression is limited to the intermediate dermis. The other EPO-regimens also reduced depth progression, affecting skin appendages (F) and preserving muscle (EPO2,500 45 min; G) or affecting both (EPO500 6 hrs; H, I). Scale bar 100 µm.