Morphological Study of Peripheral nerve Regeneration Promoted by PDLLA/NGF Compound Conduit

Objective To explore the promotive effect of biodegradable poly d, 1-lactic acid / nerve growth factor ( PDLLA/ NGF ) compound conduit on the regeneration of the injured sciatic nerve. Methods Sixty Sprague-Dawley rats randomly were averagely divided into four groups, i.e. autograft (group A), PDLLA conduit (group B), PDLLA and only one injection of NGF into conduit (group C), and PDLLA / NGF compound conduit (group D) groups. Each rat underwent right sciatic nerve transection and left a 10 mm nerve defect, and then were treated respectively according to the above-mentioned four experimental groups. The morphologic assessment of nerve regeneration was done by gross observation, resumption rates of triceps weight, histological and ultrastructural observation respectively at 1, 2, 3 months after the operation. Results There were no necrosis and ulceration in the experimental hindlimbs of all the rats. The best resumption rates of triceps weight after the operation was group A, and then was groups D, C and B in turn (P 0.05). The regenerated nerve fibers of group D were similar to that of group A and significantly superior to that of groups B and C in the histological and ultrastructural morphology (P0.05). The neurofibrillae, in which there were well developed neurofilaments and microtubules, were more dense, bigger in diameter and had thicker myelin sheaths in groups A and D than that in groups B and C. Conclusions The biodegradable PDLLA / NGF compound conduit, which has favorable compatibility with the tissues in the rats and can effectively promote injured peripheral nerves regeneration in rats, should be a potential ideal bridging material of the injured peripheral nerves.