Michael Lange; Don Rodriguez; Elijah Bingham, Brigham Young University
One of the responses following a traumatic injury to the peripheral nervous system (PNS) is an increased expression of nerve growth factor receptors (NGFR), which helps to stimulate the regeneration of the nerve. In a normal, healthy PNS, NGFRs are rarely found. Following damage to the nerve, NGFRs can be found in elevated levels around the damaged area. In this study, traumatic injury to the sciatic nerve of rats was performed to study the effects of regeneration after a local application of nerve growth factor (NGF). A combined physical crush and focal demyelination model was used to simulate the nerve injury. This study tested the administration of injections of lysophosphatidylcholine (LPC), a demyelinating agent, at Day 0 and a single injection of NGF at Day 7, and multiple injections of NGF at Days 5, 7 and 9 to determine baseline effects on crushed sciatic nerves in rats. The nerves were examined both qualitatively, using SEM and immunohistochemistry, and quantitatively, using transdermal local electrophysiology. Adding NGF to LPC-crush nerves did not provide a significantly faster result or any significant change in the percentage of functioning nerve fibers compared to crushed nerves that were not treated with NGF. The conclusion of this study was that single injections of LPC and NGF one week apart did not alter the healing rate of the sciatic nerves. Multiple treatments of NGF at 5, 7 and 9 days post-injury did not alter these results either. These observations are important to define the baseline effects of NGF and LPC injections, as part of a larger effort to determine the minimal dose regimen to regenerate peripheral nerves.