Suitable dose of nerve growth factor in the poly d, l-lactic acid/nerve growth factor compound conduit

Objective To investigate the suitable dose of nerve growth factor (NGF) in the poly d, l-lactic acid/nerve growth factor (PDLLA/NGF) compound conduit on promoting rat sciatic nerve regeneration. Methods 40 female Wistar rats were randomly assigned into five groups with 8 each. The doses of NGF in the PDLLA/NGF conduit were 100u, 250u,400u,500u,and 800u respectively. The right sciatic nerve of the animals was transected to create a 10mm gap and then bridged with PDLLA/NGF compound conduit containing different doses of NGF according to group assignment. Sciatic nerve regeneration was evaluated at 6 months following the operation by comparing motor nerve conduction velocity, muscle wet weight, myelinated nerve fiber count and axon diameter among the groups. Results Nerve regeneration in the groups containing 400u and 500u NGF was significantly superior to those in the other three groups. There was no difference between parameters of 400u NGF group and 500u NGF group. Among the 5 groups nerve regeneration was most unfavorable in the 800u NGF group. Conclusion The suitable dose of NGF in PDLLA/NGF compound conduit is around 400～500 u. Higher concentrations of NGF could inhibit nerve regeneration.