Comparison of triphenyltetrazolium dye with light microscopic evaluation in a rabbit model of acute cerebral ischaemia

The present study was performed to compare brain infarct size assessment by routine histology (haematoxylin and eosin) and by 2,3,5- triphenyltetrazolium chloride staining techniques. New Zealand white rabbits were subjected to autologous clot embolization to the anterior circulation of the brain. After a study period of 7-8 h the brains were harvested and serially sectioned in the coronal plane. Brain slices were then immersed in a 1% triphenyltetrazolium chloride dye. Following visualization of the infarcted region, the brains were immediately placed in 10% formalin and later prepared for histologic evaluation by routine haematoxylin and eosin. The two methods were compared for their ability to estimate infarct size by an independent observer. There was excellent correlation between the two methodologies; infarct sizes of 57.4 ± 5.0% versus 55.9 ± 5.4% (mean ± SEM, p < 0.007, r = 0.73, n = 12; expressed as percentage of the hemisphere infarcted) were noted for light microscopic evaluation versus triphenyltetrazolium chloride staining, respectively. It is concluded that triphenyltetrazolium chloride staining is an acceptable method for delineating brain infarct size in this rabbit model of thromboembolic stroke. The relative ease of infarct size determination with this technique suggests its more widespread use in similar models.