EFFECT OF HYALURONIDASE ON BRAIN EXTRACELLULAR-MATRIX IN-VIVO AND OPTIC-NERVE REGENERATION

In the rat, intracerebral injection of bacterial hyaluronidase resulte d in the almost complete disappearance of hyaluronic acid (HA) and gli al hyaluronate-binding protein (GHAP) from cerebral hemispheres, brain stem, and cerebellum (but not from optic nerves and chiasm) starting 2-3 hr after the injection. HA and GHAP reappeared throughout the brai n in characteristic patches 2-3 days after the injection. The patches gradually became confluent and after 12 days the brain appeared virtua lly normal. In normal rat optic nerve, staining for HA and GHAP ceased abruptly in the region of the lamina cribrosa. The retina was complet ely negative. HA and GHAP disappeared from hyaluronidase-injected opti c nerve, chiasm, and contralateral optic nerve. In hyaluronidase-injec ted crushed optic nerves, regenerated axons were able to grow for shor t distances (about 500 mum) into the distal stump undergoing Wallerian degeneration. No such growth was observed in saline-injected controls . (C) 1993 Wiley-Liss, Inc.