Abstract Details Title Validation of an Axonal Injury Model by Scanning Electron Microscopy Imaging Topic General Neurology Presentation(s) P1 - Poster Session 1 (5:30 PM-6:30 PM) Poster/Presentation Number 4-030 Objective We developed an in vitro model where a physical stress is applied to the axons in a time and force-controlled manner. One of the key novelties of our model is the possibility to image in real time changes in the axons during the injury. We validated our model by assessing axonal changes generated by the physical injury. Background Studies using different experimental settings have focused on the relationship between axonal injury and the effects on neuronal homeostasis and functionality. Axonal pathology is present in many neurodegenerative diseases, but there still is not a clear understanding of the molecular mechanisms involved in this process. Histopathology studies show that damage to axons typically appear as breaks in the axon (axotomy) or focal enlargements referred to as axonal swellings. Design/Methods Briefly, human neurons were first differentiated from NSCs and seeded in the proximal chamber with their axons elongating through a series of parallel channels ending in the distal chamber. Perpendicularly to the axonal grid an additional channel goes from side to side of the chamber, connected to a syringe controlled by an electronical device, which sets the pressure of the syringe and ultimately controls the flow through the channel. After 90 seconds of a flow rate of 100 ul/min, chambers were fixed and processed for imaging in a Scanning Electron Microscope. Images from axons across the region of injury were taken and morphometric analysis performed. Results As expected, our results show a significant increase in the number of enlargements per axon, as well as a significant decrease in the distance between adjacent enlargements. Surprisingly, enlargements size (length and width) remains unchanged when injured and control axons are compared. Conclusions Validation of the physical stress system and the results obtained open novel paths to describe and understand the molecular events that are involved in axonal response to injury. Authors/Disclosures PRESENTER No disclosure on file No disclosure on file