The intraluminal thread model revisited: rat strain differences in local cerebral blood flow

There are major differences in the outcome of focal cerebral ischemia between rat strains. This study aimed to investigate whether inter-strain differences exist in the local cerebral blood flow, changes produced by intraluminal middle cerebral artery occlusion (MCAO). Fifty-four male Long-Evans, Sprague-Dawley or Wistar rats were subjected to 60 minutes of transient MCAO, carried out with a silicone-coated 4-0 nylon monofilament. Local cerebral blood flow was monitored on the parietal cortex with laser-Doppler flowmetry. The decrease in local cerebral blood flow during the first 20 minutes of occlusion was significantly greater in Long-Evans (74.6 +/- 8.9%) than in Sprague-Dawley (50.7 +/- 26.8%) and Wistar (49.0 +/- 21.9%) rats. Strain differences in local cerebral blood flow reduction were maintained, or increased, throughout the occlusion period. These results show that the intraluminal model of MCAO produces a more pronounced, persistent and stable local cerebral blood flow reduction, with less interanimal variability, in Long-Evans than in Sprague-Dawley or Wistar rats.