Austin Thompson and David Walton, Brigham Young University
Life Sciences
When we sustain a traumatic injury to the peripheral nervous system (PNS), our bodies elicit a series of responses to try to heal the acquired damage, including inflammation and repair processes. One of these responses is the increased expression of nerve growth factor receptor (NGFR), which helps to stimulate regeneration of the nerve. In a normal, healthy PNS, NGFR is rarely found. Following damage to the nerve, NGFR can be found in high levels around the damaged area. In our study, we are simulating traumatic injury to the sciatic nerve of rats in order to study the effects of regeneration after a local application of nerve growth factor (NGF). We are using both a physical crush model and a focal demyelination model to simulate the nerve injury. In the crush model, we are examining the effect of a crushed extracellular matrix (ECM) on degeneration and subsequent regeneration. In the focal demyelination model, we are investigating the effects of local demyelination with an intact ECM on degeneration and regeneration. In two additional experimental groups, we will perform an intraneural injection of NGF into the damaged sciatic nerve one week after the crush or a lysolecithin injection at the damaged site. We are examining the nerve both qualitatively using SEM and immunohistochemistry and quantitatively using electrophysiology. This allows us to understand the role of the ECM in regeneration, and its effect on the rate of regeneration. We hypothesize that the addition of NGF in combination with the increase of NGFR after injury will increase the rate of nerve regeneration. We expect regeneration to be faster in the focal demyelination model due to the presence of intact ECM than in the crush model where the ECM is damaged.