Species differences in the trypsin separation of epidermis and dermis

Trypsin incubation was performed on split-skin grafts from rats, pigs, and humans. The separation of dermis and epidermis was best achieved when incubating in 0.5% crude trypsin in Hank's balanced salt solution. Separation occurred at 37 degrees C in 1 1/2 hours for all species. At 4 degrees C, the separation took 2 1/2 hours for pigskin, 3 1/2 to 4 1/2 hours for human skin, and 5 to 6 hours for rat skin. Histological examination showed a cleaner separation of both rat skin and pigskin was obtained at 4 degrees C than at 37 degrees C. Large areas of skin (1600 mm2) could be separated easily as long as adequate amounts of solution were used.