Radiation Protection of Mice with Bone Marrow and Spleen Preserved at Low Temperature Using Polyvinylpyrrolidone.

By MAXIM D. PERSIDSKY AND VicroR RICHARDS P OLYVINYLPYRROLIDONE (PVP), a non-polar hydrophilic polymer, has been used by a number of investigators16 as a protective agent in freezing erythrocytes. Currently it is considered one of the most effective additives in the low temperature preservation of hlood.7#{176} An early attempt, by other investigators,10 to extend the scope of PVP as a preservative to nucleated cells proved unsuccessful. However, since then we have found and reported in several communications 13 that PVP K-30 (Antara Chemicals ) in a 10 per cent concentration offers effective protection in the preser‘ation of hcne marrow at low temperatures. The viability of the preserved marrow was assessed by our technique of tissue culture and phase microscopy. Although, on the average, only 29 per cent cell survival was found, the biological inertness of PVP and the long clinical experience with this compound as a plasma expander makes it a desirable additive in the preservation of bone marrow intended for clinical use. We have, therefore, ftmrther evaluated the protective effects of PVP by transplantation of preserved isologous bone marrow into lethally irradiated mice. For a comparison, bone marrow frozen with 15 per cent glycerol was also transplanted. In addition, spleen cells preserved with 10 per cent PVP were similarly evaluated.