Microfluidic High-Throughput Methods for the Induction and Characterization of Repeatable, Titratable Traumatic Neural Injury in the Nematode Caenorhabditis elegans

White, Hamilton

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Microfluidic High-Throughput Methods for the Induction and Characterization of Repeatable, Titratable Traumatic Neural Injury in the Nematode Caenorhabditis elegans

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Traumatic brain injury (TBI) causes polymodal trauma leading to persistent changes in brain function, behavior, cellular structure, and is a known risk factor for neurodegenerative disease. Current injury models correlate the presence and duration of injury conditions with animal behavior, but they do not reveal underlying effects on brain function at the cellular and subcellular scale in a continuous, longitudinal manner. To identify underlying mechanisms relating acute brain injury with functional outcomes, we sought to develop a reliable, scalable TBI model in C. elegans to directly observe injury progression at behavioral, neurofunctional and structural levels, both immediately and over hours to days. Previously, ultrasonic shock waves and vortex-induced blunt force trauma caused paralysis in thrashing animals, with broad population variability. We investigated ultrasonic cavitation as a repeatable and titratable TBI induction method using a bath sonicator modified for precise, sub-second timing control. Video recordings during sonication revealed animals near a rigid surface were injured in a dose-dependent manner, whereas those in bulk liquid were relatively unharmed. Using an expanded and flexible optogenetic and chemical stimulation platform, repeated assessment of neural function of up to 24 hours allowed examination of structural degeneration and neurofunctional recovery. To show the platform’s usefulness, we identified sexually dimorphic outcomes in injury response, a channel inhibitor that modulates neural activity recovery post-injury via genetic and pharmacological means, and assess an ortholog of FHM1 for sensitizing animals to injury. Overall, sonication-induced TBI provides repeatable assays for real-time, in vivo recording of neuronal structure, function, and behavior, before and after single or repeated injury, enabling further study on injury mechanisms, progression, and potential therapies to minimize damage and enhance recovery.

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