title: 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: OBJECTIVE
  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 reacting microvessels showed evidence of increase contractility that coincided temporally with the decreased perfusion of cortical CBF.
  
  
  CONCLUSIONS
  Based on these observations, it is proposed that TBI causes alterations in the vascular tone of reacting microvessels which leads to prolonged vasoreactivity and restriction of the lumen in many but not all microvessels.
authors.affiliation: Department of Anatomy and Cell Biology, Scott Hall, Room No. 9312, Wayne State University School of Medicine, 540 E. Canfield, Detroit, MI 48201, USA. jrafols@med.wayne.edu
authors.forename: José A
authors.initials: JA
authors.lastname: Rafols
authors.forename: Christian W
authors.initials: CW
authors.lastname: Kreipke
authors.forename: Theodor
authors.initials: T
authors.lastname: Petrov
mesh_terms: D000818:Animals; D001808:Blood Vessels / Q000503:physiopathology* / Q000648:ultrastructure; D001930:Brain Injuries / Q000473:pathology* / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000473:pathology*; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004195:Disease Models, Animal; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008833:Microcirculation / Q000473:pathology / Q000503:physiopathology* / Q000648:ultrastructure; D046529:Microscopy, Electron, Transmission / Q000379:methods; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors