Induction of regional collateral sprouting following muscle denervation.

Objectives/hypothesis: Anecdotal clinical findings suggest that denervated muscle may regain modest functional recovery via spontaneous collateral sprouts from intact adjacent nerve fibers. The current study evaluates the conditions needed for the denervated masseter muscle to induce axonal sprouting from the facial nerve. We hypothesize that epineurial injury is required to induce collateral sprouting toward a neighboring denervated muscle.

A double-transgenic mouse used to track migrating Schwann cells and regenerating axons following engraftment of injured nerves.

We propose that double-transgenic thy1-CFP(23)/S100-GFP mice whose Schwann cells constitutively express green fluorescent protein (GFP) and axons express cyan fluorescent protein (CFP) can be used to serially evaluate the temporal relationship between nerve regeneration and Schwann cell migration through acellular nerve grafts. Thy1-CFP(23)/S100-GFP and S100-GFP mice received non-fluorescing cold preserved nerve allografts from immunologically disparate donors. In vivo fluorescent imaging of these grafts was then performed at multiple points.