Improvements in the intraluminal thread technique to induce focal cerebral ischaemia in rabbits

Although the intraluminal thread technique has been used to induce focal cerebral ischaemia in rabbits, its success rate is not high. We, therefore, attempted to improve the stability and reproducibility of this method by using thread tips of appropriate diameter as determined from the anatomical characteristics of the carotid and cerebral arteries of New Zealand white rabbits. Following intraarterial injection of casting material, we tested threads of four different tip diameters to determine the optimal thread tip that could occlude the middle cerebral artery (MCA). 2,3,5-Triphenyltertrazolium chloride (TTC) staining showed that, consistent with the intraluminal diameter of the MCA from the arterial casts ( 0.50 +/- 0.06 mm), thread with 0.51-0.55 mm tip diameter was optimal for the occlusion of the MCA. Ability to induce focal cerebral ischaemia was also dependent on variations in the anatomy of the internal carotid artery (ICA), especially the origin of the occipital artery. Our results suggest that use of appropriately sized thread and accurate manipulation of its tip significantly improves the stability and reproducibility of this model.