Cryopreservation of skin using a murine model: validation of a prognostic viability assay

In order to evaluate the many variables that can affect cryopreservation success, a simple, highly reproducible model system is required. We have evaluated the use of tetrazolium reductase activity as a prognostic indicator of skin viability in an inbred murine model. Two inbred hairless mouse strains were characterized in studies on autografting and allografting following different skin-storage protocols. Skin tetrazolium reductase (TR) activity correlated well with oxygen consumption, and with graft success--the ultimate performance criterion--following varying degrees of cryogenic injury. The assay was shown to be highly reproducible. In a series of factorial experiments the only factors affecting TR activity were those concerning the mouse donors, i.e., mouse strain, age, sex, and body area. The effects of these factors on TR activity were fully characterized.