Unlocking the Potential of the FlexCell Tension System as a Model for Human Mild Traumatic Brain Injuries (TBIs) In-Vitro

With recent federal attempts to limit the use of animals in biomedical research, it has become critical to prepare for a future more dependent on alternative models. While the gold standard model of traumatic brain injuries (TBIs) are rats subjected to a weight drop, we propose the use of primary human brain cells to model TBIs in-vitro using the FlexCell Tension System to apply physical strain. Shear strain is seen in TBIs as a consequence of acceleration-deceleration and rotational acceleration forces, e.g. sports injuries, motor vehicle accidents, and falls. It is our hypothesis that the FlexCell Tension system can be used to model shearing strain caused during TBIs, and their consequences on brain vascular integrity. Using primary human choroid plexus endothelial cells, we used the FlexCell system to administer singular and multiple strain protocols in order to mimic a TBI at a cellular level. We then collected cytokine-rich supernatant for analysis using the RnD Proteome Profiler Human Cytokine Array, which measures 28 unique cytokines. To validate this potential model, we compared our cytokine data analysis from multiple experimental and control runs to existing human literature from in-vivo TBI studies regarding initial and longitudinal cytokine production in TBI pathophysiology. In humans, elevated levels of IL-6, IL-8, IL-10, IL-18 & TNFα have been reported in cerebrospinal fluid (CSF) and serum following a TBI. These cytokine elevations are consistent with findings in our model. As human research into this subject is traditionally retrospective and opportunistic, often focusing on TBIs admitted to hospitals (usually moderate-severe Glasgow Coma Scale (GCS)), the shift toward in-vitro research could be vital in TBI studies. Given the similarities between our study results and previous in-vivo human studies, this yields a promising direction to further our research. Additional controlled research is needed to further confirm whether the increased pro-inflammatory cytokines in human models are due to central nervous system (CNS) damage and dysfunction, or rather due to the crossing of peripheral cytokines through the blood-brain and blood-CSF barriers. If validated, we believe this model could lead to evaluation of other cell types in TBI and eventually a co-culture to examine the combinatorial effects of TBI on cells of the CNS. This project was supported by Faculty Research Development (FRD) grants from Marian University Wood COM and a Senior Research Grant from the Indiana Academy of Science. This abstract was presented at the American Physiology Summit 2025 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.