OCT imaging of acute vascular changes following mild traumatic brain injury in mice(Conference Presentation)

While most people recover completely from mild traumatic brain injuries (mTBIs) and concussions, a subset develop lasting neurological disorders. Understanding the complex pathophysiology of these injuries is critical to developing improved prognostic and therapeutic approaches. Multiple studies have shown that the structure and perfusion of brain vessels are altered after mTBI. It is possible that these vascular injuries contribute to or trigger neurodegeneration. Intravital microscopy and mouse models of TBI offer a powerful platform to study the vascular component of mTBI. Because optical coherence tomography based angiography is based on perfusion contrast and is not significantly degraded by vessel leakage or blood brain barrier disruption, it is uniquely suited to studies of brain perfusion in the setting of trauma. However, existing TBI imaging models require surgical exposure of the brain at the time of injury which conflates TBI-related vascular changes with those caused by surgery. In this work, we describe a modified cranial window preparation based on a flexible, transparent polyurethane membrane. Impact injuries were delivered directly through this membrane, and imaging was performed immediately after injury without the need for additional surgical procedures. Using this model, we demonstrate that mTBI induces a transient cessation of flow in the capillaries and smaller vessels near the injury point. Reperfusion is observed in all animals within 3 hours of injury. This work describes new insight into the transient vascular changes induced by mTBI, and demonstrates more broadly the utility of the OCT/polyurethane window model platform in preclinical studies of mTBI.