PROLONGED SURVIVAL OF TRANSECTED NERVE-FIBERS IN C57BL OLA MICE IS ANINTRINSIC CHARACTERISTIC OF THE AXON/

Transected axons in C57BL/Ola mice survive for extraordinary lengths o f time as compared to those of normal rodents. The biological differen ce in the substrain that confers the phenotype of prolonged axonal sur vival is unknown. Previous studies suggest the 'defect' to be a proper ty of the nervous system itself, rather than one of haematogenous cell s. Neuronal or non-neuronal elements could be responsible for this phe notype. This study was undertaken to determine whether Schwann cells, the most numerous of the non-neuronal cells intrinsic to the periphera l nerve, are responsible for delayed degeneration of transected axons. We created sciatic nerve chimeras by transplanting nerve segments bet ween standard C57BL/6 and C57BL/Ola mice, allowing regeneration of hos t axons through the grafts containing donor Schwann cells. These nerve s were then transected and the time course of axonal degeneration was observed. The results show that fast or slow degeneration is a propert y conferred by the host, and therefore cannot be ascribed to the Schwa nn cells. Similarly, transected C57BL/Ola axons in explanted dorsal ro ot ganglia cultures survived longer than transected axons from standar d mice. Taken together these results indicate that the responsible abn ormality is intrinsic to the C57BL/Ola axon.