Transplantation of an acutely isolated bone marrow fraction repairs demyelinated adult rat spinal cord axons

The potential of bone marrow cells to differentiate into myelin-forming cel ls and to repair the demyelinated rat spinal cord in vivo was studied using cell transplantation techniques. The dorsal funiculus of the spinal cord w as demyelinated by x-irradiation treatment, followed by microinjection of e thidium bromide. Suspensions of a bone marrow cell fraction acutely isolate d from femoral bones in LacZ transgenic mice were prepared by centrifugatio n on a density gradient (Ficoll-Paque) to remove erythrocytes, platelets, a nd debris. The isolated cell fraction contained hematopoietic and nonhemato poietic stem and precursor cells and lymphocytes. The cells were transplant ed into the demyelinated dorsal column lesions of immunosuppressed rats. An intense blue beta -galactosidase reaction was observed in the transplantat ion zone. The genetically labeled bone marrow cells remyelinated the spinal cord with predominately a peripheral pattern of myelination reminiscent of Schwann cell myelination. Transplantation of CD34(+) hematopoietic stem ce lls survived in the lesion, but did not form myelin. These results indicate that bone marrow cells can differentiate in vivo into myelin-forming cells and repair demyelinated CNS. GLIA 35:26-34, 2001. (C) 2001 Wiley-Liss, Inc .