EARLY AXONAL REGENERATION - REPRESSION BY SCHWANN-CELLS AND A PROTEASE
No Thumbnail Available
Date
1995
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
We have proposed that mature Schwann cells and an extracellular protease repress the sprouting response of axons. To test this hypothesis, we destroyed all cells by freezing a short span of the rat sciatic nerve or inhibited proteases with subperineurial injections of aprotinin, and a crush was made to induce the sprouting response. In unconditioned or in vehicle-injected nerves, axons began to elongate at a constant rate after a delay of about 1 day. The freezing of the nerve distal to the crush obliterated the delay, but the rate of elongation did not change. A similar pattern was observed when the nerve segment was conditioned with aprotinin for 2 days prior to the crush. These effects were abolished when a short untreated segment was left between crush and conditioned region of the nerve. The electron microscopy of the nerve and the immunolocalization of the growth-associated protein (GAP-43) were consistent with the enhanced regrowth observed in conditioned nerves. Our findings support the notion that Schwann cells repress the onset of regeneration and that a local protease is involved. (C) 1995 Academic Press, Inc.