Erythrocyte spermidine as a biomarker for focal cerebral infarction in rat

Polyamine metabolism has been studied in rat brains subjected to focal and global cerebral ischemia injury by measuring levels of the polyamines putrescine, spermidine and spermine in the brain. However, little is known about erythrocyte polyamine changes in ischemic rat. The aim of our study was to compare the sequential erythrocyte polyamine levels with brain injury volume after focal cerebral infarction following reperfusion. Middle cerebral artery was occluded for 2.5 hours in male Sprague-Dawley rats by an intraluminal suture method. The brain injury area was negatively correlated with erythrocyte spermidine levels from 48 to 96 hours after onset of the infarction event (n=14, r=-0.86, p<0.01). Time-dependent changes of erythrocyte spermidine were markedly decreased at 48, 72 and 96 hours after cerebral infarction, compared with sham-operated group or normal group. These results suggest that erythrocyte spermidine is a useful biomarker for measuring the infarct volume after middle cerebral artery occlusion following reperfusion in rat.