The Experimental Research Of PDLLA/NGF Compound Conduit On Restoring Rat Sciatic Nerve Defect

Objective To evaluate the dose effect of poly d,l-lactic acid/nerve growth factor(PDLLA/NGF) compound conduit on restoring rat sciatic nerve defect and the suitable dose of NGF in PDLLA/NGF compound conduit.Methods 24 female wistar rats were randomly assigned into three groups: PDLLA(A group,n=8), PDLLA/NGF compound conduit with 800 NGF(B group,n=8), PDLLA/NGF compound conduit with 400 NGF(Cgroup,n=8).The other 40 female wistar rats were randomly assigned into five groups: PDLLA/NGF compound conduit with 100 NGF(D group,n=8. 250 U(E group,n=8). 400 U(F group,n=8). 500 U(G group,n=8. 800 U(H group,n=8).Each rat underwent right sciatic nerve transection and kept a 10mm nerve defect , then these defects were repaired in three different experimental groups. Function repair of sciatic nerve regeneration was evaluated at 3 months following operation by using gross observation, triceps weight, electrophysiological, histological and axon morphologic assessment of the outcome of nerve regeneration in the first three groups(group A,B and C). In the other five groups, function repair of sciatic nerve regeneration was evaluated at 6 months following operation by using gross observation, triceps weight, electrophysiological assessment.Results There were no cecrosis and ulceration in hindlimb of the experimental. At 3 months following operation, nerve regeneration in group C was significantly superior to that in group A and B in nerve conduct velocity(NCV),triceps weight and axon morphologic index. Though there were no significant difference between group B and group A in NCV and triceps weight, there were significant difference in axon morphologic index and that in group A was superior that in group B in axon morphologic index. At 6 months following operation, nerve regeneration in group F and G was significantly superior to that in group D, E and H in nerve conduct velocity(NCV), triceps weight. There were no significantly different in group F and G.Conclusions 1. NGF of PDLLA/NGF compound conduit may repair the sciatic nerve in a dose-dependent manner. Suitable dosage of NGF can promote nerve regeneration, but too high dosage can inhibit nerve regeneration. 2. The suitable dose of NGF in PDLLA/NGF compound conduit is about 400-500U.