Effects of different preservation solutions on skin graft epidermal cell viability and graft performance in a rat model

This study sought to evaluate the viable epidermal cell count of skin stored at 4 °C in different media, and to determine the longest time that grafts could be stored and still be used for clinical application of skin grafts. Harvested rat skin grafts were divided into four groups: saline (group 1), Roswell Park Memorial Institute-1640 solution (RPMI) (group 2), University of Wisconsin solution (UW) (group 3), and Histidine–tryptophan–ketoglutarate solution (HTK) (group 4). After the designated storage time (7, 14, 21, 28, or 35 days), grafts were divided into two parts. Skin grafts (3 cm × 3 cm) were then autotransplanted onto full-thickness circular wound beds. Percentages of viable keratinocytes (PVK) declined significantly for skin grafts stored in UW, HTK, and saline solutions (Kruskal–Wallis, P < 0.05), while there was an insignificant decline in the PVK of skin grafts stored in RPMI until the 28th day of storage (Kruskal–Wallis, P > 0.05). Compared with UW, HTK, and saline, grafts stored in RPMI had significantly higher percentages of PCNA at the 14th and 21st days of storage (Mann–Whitney U-test, P < 0.05). Grafts stored in RPMI had significantly lower apoptosis rates than did grafts stored in UW or HTK (P < 0.05). Based on these results, we conclude that RPMI-1640 provides a better environment for skin grafts by increased quality and survival time of skin grafts, as assessed by both microscopic and macroscopic investigations.