PROLONGED AXONAL SURVIVAL IN TRANSECTED NERVES OF C57BL OLA MICE IS INDEPENDENT OF AGE/

Interrupted nerve fibres from the C57BL/Ola strain of mouse degenerate after an extraordinary delay compared to nerves of standard laborator y mice. Other investigators, using electrophysiologic methods, conclud ed that the mutant phenotype diminishes with age, implying that the mu tation in C57BL/Ola mice affects a developmentally regulated gene. In an effort to confirm this observation, we studied the course of Waller ian degeneration in C57BL/Ola mice aged 1 through 16 months by using q uantitative morphometry, immunohistochemistry, and immunoblotting but found the period of axonal survival after nerve transection to be no d ifferent in old versus young C57BL/Ola mice. We conclude that the C57B L/Ola phenotype of prolonged survival of transected nerves is not affe cted by age, although certain physiologic measures may degrade in olde r animals. The persistence of axoplasm after nerve injury in C57BL/Ola mice may be the feature most closely related to the function of the m utant gene.