Characterization of Vascular Disruption and Blood-Spinal Cord Barrier Permeability following Traumatic Spinal Cord Injury

Significant vascular changes occur subsequent to spinal cord injury (SCI), which contribute to progressive pathophysiology. In the present study, we used female Wistar rats (300-350 g) and a 35-g clip-compression injury at T6 to T7 to characterize the spatial and temporal vascular changes that ensue post-SCI. Before sacrifice, animals were injected with vascular tracing dyes (2% Evans Blue (EB) or fluorescein isothiocyanate/Lycopersicon esculentum agglutinin [FITC-LEA]) to assess blood-spinal cord barrier (BSCB) integrity or vascular architecture, respectively. Spectrophotometry of EB tissue showed maximal BSCB disruption at 24 h postinjury, with significant disruption observed until 5 days postinjury (p<0.01). FITC-LEA-identified functional vasculature was dramatically reduced by 24 h. Similarly, RECA-1 immunohistochemistry showed a significant decrease in the number of vessels at 24 h postinjury, compared to uninjured animals (p<0.01), with slight increases in endogenous revascularization by 10 days postinjury. White versus gray matter (GM) quantification showed that GM vessels are more susceptible to SCI. Finally, we observed an endogenous angiogenic response between 3 and 7 days postinjury: maximal endothelial cell proliferation was observed at day 5. These data indicate that BSCB disruption and endogenous revascularization occur at specific time points after injury, which may be important for developing effective therapeutic interventions for SCI.