Myelin formation in myelin-deficient rat spinal cord following transplantation of normal fetal spinal cord.

Previous studies of the myelin-deficient rat spinal cord have suggested that astrocytes may play a role in preventing the formation of myelin in this mutant, or causing its breakdown. Comparison of mutant and normal littermate spinal cords shows a marked hypertrophy of astrocytes in the mutant in both gray matter and fiber tract regions. Nevertheless, when normal fetal spinal cord fragments are transplanted into mutant host spinal cord, clusters of normal-looking myelin sheaths develop with no sign of attack by host astrocytes.