Protection by Glycerol, Sucrose and Trehalose for Acellular Human Dermis Against Gamma Irradiation Damage at -78.5°C.

BACKGROUND: Glycerol, sucrose and trehalose are used as protectants for membrane, protein, cell and tissue preservation. The undercooled state (glassy or rubbery) of their solutions may also offer protection for protein, cells and tissues against radiation damage upon sterilization. OBJECTIVE: The study aimed to examine the protective effects of glycerol, sucrose and trehalose on cryopreserved acellular human dermis against gamma irradiation damage. MATERIALS AND METHODS: Acellular human dermis was cryopreserved at -80°C in glycerol, sucrose and trehalose solutions or their combinations with a base citrate-phosphate buffer (pH 6.0). Cryopreserved acellular dermis was then subjected to 13 kGy gamma irradiation at -78.5°C, and radiation damage was assessed by histological evaluation. RESULTS: Freeze and thaw alone do not alter the structure of acellular dermis, but gamma irradiation at -78.5°C results in significant structural changes in acellular dermis, including the formation of large holes, the damage of collagen fibers and the loss of overall dermis tissue histology. The incorporation of glycerol, sucrose and trehalose into cryopreservation solutions reduces gamma irradiation-induced tissue structural damage considerably. When used alone, trehalose (0.5 M) provided better protection against gamma irradiation damage than did sucrose (0.5 M) and glycerol (1.0 M). When used in combination, the glycerol and trehalose combination provides the best tissue protection. Significant donor-to-donor variation exists in tissue damage after gamma irradiation. For donor dermis that is less sensitive to gamma irradiation damage, glycerol, sucrose or trehalose alone is able to provide good protection. However, for more sensitive donor dermis, only the glycerol and trehalose combination is able to provide sufficient tissue protection. CONCLUSION: Glycerol, sucrose and trehalose protects cryopreserved acellular human dermis against gamma irradiation damage. Cryopreservation solutions can be optimized to permit tissues for gamma sterilization to increase the safety human tissue implants.