Objectives: Neural cell dysfunction occurs at the time of an insult to the brain, yet the thresholds to high-rate strains are poorly understood. The objective of this study was to develop a finite element modeling (FEM) platform to examine stress and strain at the time of insult as a function of cellular permeability in the minutes following the insult in a controlled cortical impact (CCI) model of TBI. Hypothesis: We hypothesized that high spatial resolution finite element analysis of the rat brain during a unilateral CCI will reveal subregional stress and strain differences that correlate with areas containing permeabilized cells. Participants: None. Methods: A 3D FEM of a rat brain was developed, and simulations of CCI were run to calculate the maximum principal strain (MPS) and maximum shear strain (MSS). Lucifer yellow was injected into the CSF of adult male rats, followed by CCI (n = 4) or sham injury (n = 2).1 Animals were perfused with fixative 10 min after the insult and cells containing lucifer yellow were counted and the mapped to the FEM. Results: MPS and MSS were found to be the largest through the center of the impactor. Layers corresponding to the hippocampus exhibited higher levels of strain than the surface layer. Plasma membrane disruptions occurred throughout the cerebral cortex and hippocampal regions. Cerebral cortex uptake was more pronounced in the areas medial to the injury site and throughout the hippocampal regions. Conclusions: These data link the mechanical insult to subsequent cell damage seen in TBI. By using FEM, cell response can be correlated to strain patterns in order to better understand injury mechanisms. Areas of increased strain were found to positively correlate with areas containing high numbers of positive cells.

Acknowledgment

This study was supported by the NHTSA (DTNH22-01-H-07551 to UAB, SCIB).

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