REGENERATION OF DORSAL COLUMN AXONS AFTER SPINAL-CORD INJURY IN YOUNG-RATS

In contrast to previous reports denying the occurrence of axonal regen eration of the dorsal column (DC) projections, here we demonstrate for the first time that marked regeneration occurs spontaneously after tr ansection in infant rats. Transection was made sharply so as to produc e edema-free lesions without subsequent formation of either scars or c ysts. Transganglionic labeling of axons revealed that regenerated axon s ascended in the normal tract in a manner similar to normal projectio ns as a tightly-packed fasciculus and terminated densely in the nucleu s gracilis. The present study indicates that failure of regeneration o f DC axons is due to neither intrinsic deficiency of regrowth potentia l nor global ly-inhospitable axonal environment but rather the local c onditions of the lesion site. (C) 1998 Elsevier Science Ireland Ltd. A ll rights reserved.