Matrix metalloproteinase-9 is associated with blood-brain barrier opening and brain edema formation after cortical contusion in rats

Acta Neurochir Suppl. 2006;96:130-3. doi: 10.1007/3-211-30714-1_29.

Abstract

Matrix metalloproteinases (MMPs) are associated with blood-brain opening and may be involved in the pathophysiology of acute brain injury. Previous research demonstrated that knockout mice deficient in MMP-9 subjected to transient focal cerebral ischemia had reduced blood-brain barrier (BBB) disruption and attenuated cerebral infarction. In this study, we examined MMP-9 up-regulation, BBB disruption, and brain edema formation after cortical impact injury in rats. Cortical contusion was induced by controlled cortical impact. Animals were sacrificed at intervals after injury. MMP up-regulation was assessed by gelatin zymography, and BBB integrity was evaluated using Evans blue dye with a spectrophotometric assay. Brain water content was measured by comparing wet and dry weights of each hemisphere as an indicator of brain edema. Zymograms showed elevated MMP-9 as early as at 3 hours after injury, reaching a maximum at 18 hours. Peak levels of BBB disruption occurred 6 hours after injury. Brain edema became progressively more severe, peaking 24 hours after injury. Compared to control group, treatment with MMP-inhibitor GM6001 significantly reduced BBB disruption 6 hours and brain water content (85.9 +/- 0.5% vs. 82.6 +/- 0.3%; p < 0.05) 24 hours after injury. These findings suggest that MMP-9 may contribute to BBB disturbance and subsequent brain edema after traumatic brain injury.

MeSH terms

  • Animals
  • Blood-Brain Barrier / physiopathology*
  • Brain Edema / etiology
  • Brain Edema / physiopathology*
  • Brain Injuries / complications
  • Brain Injuries / physiopathology*
  • Cell Membrane Permeability
  • Male
  • Matrix Metalloproteinase 9 / metabolism*
  • Rats
  • Rats, Wistar

Substances

  • Matrix Metalloproteinase 9