A novel method of detecting rCBF with laser-Doppler flowmetry without cranial window through the skull for a MCAO rat model

Background and purpose: In a rat model of middle cerebral artery occlusion (MCAO) with intraluminal technique, lesion volume and its reproducibility vary among laboratories. Although laser-Doppler flowmetry (LDF) is useful to optimize the reliability, conventional methods require a craniotomy and special apparatus. The purpose of this study was to evaluate a novel approach for LDF monitoring of rCBF through lateral aspect of the skull without a craniotomy. Methods: SD rats were subjected to 45 min of MCAO using an intraluminal thread. MCAO was achieved by an examiner who had been trained 4 weeks for making the model with no LDF monitoring (Group-1, n = 12), while in the other group, the same examiner induced MCAO using a novel approach of LDF monitoring (Group-2, n = 12). rCBF was detected through an LDF probe attached to the lateral aspect of the skull. The survival rate and the infarct volume were estimated for comparison between the two groups 2 days after MCAO. Results: The mortality rate was 25% in Group-1 and 0% in Group-2. The lesion volume of the cortex in Group-2 was 167.21 +/- 48.54 min 3 (mean +/- SD), which was larger than that in Group-1 (112.77 +/- 36.03 mm(3), P = 0.026). The coefficient variation of the lesion volume was smaller in Group-2 (29%) than in Group-1 (35%), indicating better reproducibility of the lesion volume in Group-2 than in Group-1. Conclusions: The approach of LDF monitoring through the lateral aspect of skull was useful for making large consistent infarct with reducing intraanimal variability and unexpected animal death for rat MCAO model. (c) 2005 Elsevier B.V. All rights reserved.