(Dr. Suresh Sitaraman, advisor)

"Response of Neurons Cultured in 2-D and 3-D to Dynamic Shear Deformation"

Abstract

Current in vitro models of traumatic brain injury (TBI) have evaluated post-injury alterations in cell biochemistry and viability by utilizing two-dimensional (2-D) cellular injury models, a contrast from the three-dimensional (3-D) architecture of native brain that could lead to a deviation in the injury response. It is unknown whether a differential response to high rate shear deformation - the most prevalent type of deformation in TBI - will exist between cells cultured in 2-D and 3-D. In order to evaluate possible differences in the response to a mechanical insult, neurons were plated in 2-D and 3-D configurations within a 3-D matrix. Uninjured cultures were characterized based on phenotype, viability, and neurite outgrowth. Furthermore, 2-D and 3-D neuronal cultures were plated inside a custom device capable of reproducibly imparting high strain rate simple shear deformation throughout the cell-containing matrices. After high rate shear deformation cells cultured in a 3-D orientation experienced a significant decrease in cell viability versus the cells in a 2-D orientation, suggesting that in this injury paradigm, the orientation of the cells within the strain field contributes to the response. These results establish fundamental characteristics of primary cortical neurons in 2-D and 3-D configurations and, furthermore, show differences in the response of these cell cultures to high rate shear deformation, indicating a role for cell orientation and interaction in the response to a mechanical insult. Accurate cellular models of TBI are important to develop mechanistically-driven intervention strategies and can therefore serve as valid pre-animal and pre-clinical test beds.