Collateral sprouts are replaced by regenerating neurites in the wounded corneal epithelium

Following various types of wounds and subsequent denervation, the reinnervation of the rabbit corneal epithelium was found to occur in two distinct phases that overlapped in time. In the first phase large numbers of collateral sprouts originated from the unmyelinated plexus at various distances proximal to the site of transection. Light and electron microscopic observations revealed that the sprouts began to degenerate about 7 days after wounding. Collateral sprouts were replaced by an equally numerous population of regenerating neurites extending from the transected stumps of the pre-terminal axons. We conclude that, in the wounded cornea, normal neurology is reconstituted by regenerating neurites, and not by collateral sprouts, which proliferate and then degenerate early in the healing process.