Development and Application of In Vitro Compartmentalized Devices to Study Axonal Injury

Nerve injury;nerve regeneration;microfabrication;Biomedical Engineering

Siddique, RezinaHoke, Ahmet ;

Johns Hopkins University

关键词: Nerve injury;    nerve regeneration;    microfabrication;    Biomedical Engineering;   

Others  :  https://jscholarship.library.jhu.edu/bitstream/handle/1774.2/37895/SIDDIQUE-DISSERTATION-2015.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: JOHNS HOPKINS DSpace Repository

【 摘 要 】

Regeneration of injured peripheral nervous system (PNS) axons is a widely ob- served, but incompletely understood phenomenon. While PNS axons are capable of spontaneous regeneration, functional recovery may be difficult to achieve. The com- plex in vivo environment provides a challenging setting to examine axonal injury and regeneration, making reductionist in vitro approaches necessary. Cell culture-based injury platforms allow for injury of individual axons while organotypic platforms more closely resemble the in vivo injury environment. This dissertation presents the development and application of novel compartmentalized in vitro platforms, first presenting cell culture devices and culminating with an organotypic (slice culture) platform, to enable study of the site of action of degenerating and regenerating com- pounds on PNS axons. First, microfluidic devices were utilized to determine that the chemotherapeutic agent paclitaxel is most destructive when applied to the axon, and that this chemotherapy-induced axonal degeneration can be limited by application of erythropoietin to either the cell body or axon, indicating that local mechanisms can be counteracted through cellular mechanisms. Next, regenerative effects of members of the glial cell-line derived nerve growth factor (GDNF) family of ligands (GFLs) were investigated in a microfluidic physical injury model. All tested GFLs enhanced regeneration regardless of site of application, with GDNF showing the most enhancement. Concurrent application of a retrograde transport blocker with GDNF diminishes this regenerative effect, indicating the importance of cellular rather than local mechanisms. Finally, a two-compartment culture device that enables control of the local environment of regenerating adult motor axons was developed and opti- mized, and functional compartmentalization demonstrated. This device is the first of its kind and allows for tailoring of the immediate environment of adult motor axons regenerating within the three-dimensional structure of peripheral nerve. The ability to study axonal injury and regeneration in such highly tailorable environments will lead to more comprehensive understanding of injury and regeneration, aiding eventual goals of improving reinnervation accuracy and surgical outcomes.