Enhancement of rat sciatic nerve regeneration by fibronectin and laminin through a silicone chamber

In this study, the authors examined the effects of fibronectin and laminin on sciatic nerve regeneration in rats. Sixty-eight Sprague-Dawley rats underwent bilateral sciatic nerve transections and silicone tubulizations, with a 10-mm gap between the proximal and distal nerve stumps. Thirty rats (n=30) received 10 mug of fibronectin injection into the right sciatic nerve chamber, while saline was injected into the left nerve chamber, serving as the control. Another 30 rats (n=30) were given 6 mug of laminin injection into the right nerve chambers and saline into the left chambers. At 1, 3, and 4 months postoperatively, electrophysiologic and histologic examinations, including nerve morphometry, were performed. Eight additional rats, receiving fibronectin (n=4) and laminin (n=4) injections, were used for horseradish peroxidase (HRP) tracing at 3 months postoperatively. Results from the study showed that fibronectin- and laminin-treated groups had significantly higher motor nerve conduction velocity and evoked muscle action potential amplitude of the anterior tibial muscle than the control group (p<0.01). Nerve diameter and the number of myelinated axons from the groups receiving fibronectin and laminin applications were greater than the controls (p<0.01). Also, a greater number of HRP-labeled motor neurons were found in the ventral horns and dorsal root ganglia of the fibronectin- and laminin-treatment groups compared to the controls. The authors conclude that local applications of fibronectin and laminin into the nerve chambers can significantly improve axonal regeneration and maturation of injured rat sciatic nerves.