MYELINATION BY CRYOPRESERVED XENOGRAFTS AND ALLOGRAFTS IN THE MYELIN-DEFICIENT RAT

This study examined the ability of freshly prepared and cryopreserved canine oligodendrocytes to myelinate axons following transplantation i nto the myelin deficient (md) rat. The effects of immunosuppression, a nd the age of the donor tissue, were also examined. Canine glial cells , dissociated from the spinal cords at E50, P2, P20, P28, and P50, wer e transplanted into the spinal cords of myelin-deficient rats as singl e cell suspensions. Both cryopreserved (E50 and P28) and freshly disso ciated tissue (P2, P20, and P50) were able to form myelin within 13 da ys of transplantation. Cells from younger donors (<P20) myelinated mor e md axons than those from older donors. In those rats which received xenografts and which were treated with cyclosporin A there was markedl y less cellular infiltration than in untreated animals. For comparison with these xenografts, fresh and cryopreserved adult rat glia were al so transplanted. Eight days after transplantation, myelination by allo grafts of cryopreserved rat glia was qualitatively similar to that pro duced by freshly prepared cells. These results show that oligodendrocy tes transplanted as xenografts are capable of myelinating rat axons, a nd that cryopreserved glia retain their capacity to myelinate in vivo. (C) 1994 Academic Press, Inc.