Grant: Master's Award: Canada Graduate Research Scholarships - Master's program

Traumatic brain injury (TBI) is a major public health concern and the leading cause of mortality in young adults. Although most TBIs are mild (mTBI), these “concussions” can produce diffuse injury and prolonged recovery. Repeated or subconcussive impacts (r-mTBI) further increase vulnerability, causing more severe and lasting neurological deficits. Microvascular dysfunction is a key mechanism underlying this susceptibility. Mild impacts can disrupt the blood–brain barrier (BBB), generating microbleeds that often evade MRI but persist for weeks, allowing hemoglobin breakdown products and blood proteins—especially fibrinogen—to enter the brain. Fibrinogen activates microglial signaling, promoting localized inflammation and synaptic disruption. However, its spatial relationship to microbleeds in a realistic r-mTBI model remains unclear. Using a lateral impact model that mimics human rotational forces, we will test whether r-mTBI-induced microbleeds act as focal sites of BBB disruption and microglial activation. Male and female rats will undergo r-mTBI, with brains collected at 24 h and 7 days post-injury. Microbleeds will be visualized and quantified, and adjacent sections will be immunolabeled to assess fibrinogen deposition and microglial morphology. This project is novel in combining a physiologically relevant lateral impact model, high-resolution mapping of microbleeds and fibrinogen, and integrated analysis of microglial responses. Findings will clarify how early microvascular injury drives neuroinflammation in r-mTBI and may identify biomarkers and therapeutic targets to reduce long-term cognitive deficits.