Integrated study of the structural and metabolic degeneration of skin during 4 degrees C storage in nutrient medium

Integrated studies of the structural and metabolic degradation of skin during 4 degrees C refrigerated storage in Eagle's minimal essential medium were undertaken. Skin degeneration occurred in three phases during the first 7 weeks of refrigeration. Phase I (Days 1-10) was characterized by the release of cellular debris and leakage of intracellular enzymes into the storage medium, shrinkage of the epithelium, and vacuolization and cell loss in the vascular bundles of the papillary dermis. The release of debris was accelerated by a 2-hr incubation of the skin at 25 and 37 degrees C prior to 4 degrees C storage. The ability of dermal cells to metabolize glucose, aspartic acid, glutamic acid, ornithine, and orotic acid to carbon dioxide dropped to low levels during Phase I. Phase II (Days 11-30) was characterized by a period of less intense physical decay, but with continued cellular and vascular degeneration. By the third week, there was nearly total loss of recognizable vascular bundles in the papillary dermis. Phase III (Days 31-58) was characterized by the exfoliation of large amounts of cellular debris and significant loss of structural integrity. By the fifth week, nearly all of the nuclei in the epidermis became pyknotic, and the vascular bundles of the reticular dermis were lost. Previous reports of the maximum allowable duration of skin storage at 0-8 degrees C have ranged from 0.3 to 185 days; however, our findings suggest that the useful limit of refrigerated skin storage in nutrient medium is 1 week if physiological function and structural integrity are desired for optimum postgraft performance.