Alterations in cerebral cortex microvessels and the microcirculation in a rat model of traumatic brain injury: a correlative EM and laser Doppler flowmetry study

Abstract Objectives: We sought to establish the temporal association of fluctuations in cortical cerebral blood flow (CBF) with ultrastructural alterations of microvessels in rat sensorimotor cortex (smCx) following administration of a rodent acceleration impact model of traumatic brain injury (TBI). Methods: Laser Doppler flowmetry (LDF) and electron microscopy (EM) were used in parallel experiments that lasted for up to 48 hours after induction of TBI. Results: Compared to sham-operated control, there was a 37% reduction of cortical CBF between 12 and 24 hours, this reduction remaining unchanged for up to 48 hours post-TBI. Ultrastructural alterations in the lumen and wall of smCx microvessels, including endothelial cell distortion and luminal collapse, were seen at hour 1 and continued up to 48 hours after trauma. Compared to control, there was a 40% decrease in the average microvascular luminal area 4 hours and a trend to recover (21%) by 48 hours after trauma. Smooth muscle (SM) in the wall of reacti...