THE EFFECT OF PRESERVATION PROCEDURES AND RADIATION STERILISATION CONDITIONS ON CONNECTIVE TISSUE GRAFTS AND THEIR CONSTITUENTS

ABSTRACT The Central Tissue Bank, established in 1963, and two other multi-tissue banks operating in Poland provide connective tissue allografts such as bone, cartilage, tendons, sclera, skin, acellular dermis and amnion. All grafts are radiation sterilised with a dose of 35 kGy in a 60 Co source and/or with electron beam 10 MeV accelerator. Over 250,000 radiation-sterilised tissue grafts have been prepared and used in hospital departments throughout Poland and not one case of infectious disease transmission has been reported to date. High doses of ionising radiation can evoke numerous chemical and physical changes that may affect biological quality of tissue allografts, such as osteoinductive potential of bone, the mechanical properties of bone and other connective tissue grafts as well as the rate of their resorption in vivo . The origin and stability of free radicals and other paramagnetic entities radiation-induced in bone will be discussed. The effect of various preservation procedures (e.g. lyophilisation, deep-freezing) and radiation sterilisation conditions (doses, temperature of irradiation) on osteoinductive potential of bone as well as on degradation of collagen, a major constituent of connective tissue grafts, will be presented. The results of interdisciplinary research performed at the Central Tissue Bank in Warsaw, in collaboration with radiation chemists from the Institute of Nuclear Chemistry and Technology indicate, that radiation-induced changes can be diminished by modification of tissue preservation methods and that, to some extent it is possible to reduce undesired radiation-induced damage to the tissue grafts.