Recently, there has been increased concern about microstructural brain changes after head trauma. Clinical studies have investigated a neck collar that applies gentle bilateral jugular vein compression, designed to increase intracranial blood volume and brain stiffness during head trauma, which neuroimaging has shown to result in a reduction in brain microstructural alterations after a season of American football and soccer. Here, we utilized a swine model of mild traumatic brain injury to investigate the effects of internal jugular vein (IJV) compression on histopathological outcomes after injury. Animals were randomized to collar treatment (n = 8) or non-collar treatment (n = 6), anesthetized and suspended such that the head was supported by breakable tape. A custom-built device was used to impact the head, thus allowing the head to break the tape and rotate along the sagittal plane. Accelerometer data were collected for each group. Sham injured animals (n = 2) were exposed to anesthesia only. Following single head trauma, animals were euthanized and brains collected for histology. Whole slide immunohistochemistry was analyzed using Qupath software. There was no difference in linear or rotational acceleration between injured collar and non-collar animals (p > 0.05). Injured animals demonstrated higher levels of the phosphorylated tau epitope AT8 (p < 0.05) and the inflammatory microglial marker IBA1 (p < 0.05) across the entire brain, but the effect of injury was markedly reduced by collar treatment (p < 0.05) The current results indicate that internal jugular venous compression protects against histopathological alterations related to closed head trauma exposure.
Keywords: immunohistochemistry; mild traumatic brain injury; phosphorylated tau.
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